p1682
10-09-2011, 10:46 AM
#1
p1682
hello i am new here my name is john
i have a 2007 z06
on the forum here somebody posted a question
having problems with code p1682
i have the same problem i hope anyone can help me
if i clear all the codes the engine light stays off
as long as i put it in reverse when i turn it of
if it's not in reverse the light will go on and the p1682 code is there again
and the engine keeps running rough until i put in in reverse afther that it shuts of normal
when i start it the next time there is noting wrong except for the engine light
i replaced the start button for a new one
so that's not the problem
does anybody have an idea ?
thanks john
i have a 2007 z06
on the forum here somebody posted a question
having problems with code p1682
i have the same problem i hope anyone can help me
if i clear all the codes the engine light stays off
as long as i put it in reverse when i turn it of
if it's not in reverse the light will go on and the p1682 code is there again
and the engine keeps running rough until i put in in reverse afther that it shuts of normal
when i start it the next time there is noting wrong except for the engine light
i replaced the start button for a new one
so that's not the problem
does anybody have an idea ?
thanks john
10-09-2011, 10:51 AM
#2
Team Owner
If you don't get a suitable answer here, try posting in the Z06 forum.
http://forums.corvetteforum.com/c6-z06-discussion-100/
http://forums.corvetteforum.com/c6-z06-discussion-100/
09-30-2016, 11:09 AM
#4
Error Codes P1516, P1682, P2176, and U0101.
I had all these error codes come up on my 2005 C6. I started driving car in April 2016 with no problems until just this September.
Doing research on Corvette Forum and other locations on the internet I found many horror stories and also how elusive these error codes can be. Specifically many people replacing their TCM, batteries, and a host of other parts without a real resolution to the problem.
Here are all the symptoms the C6 was displaying:
Check engine light steady on
Security light steady on
DIC- displaying Service traction System
DIC – Not reading transmission fluid temperature
Engine dieseling at shutoff for up to 10 seconds
No power at the low end
Heads up display not functioning properly
Instrument cluster not working
Rough idle upon starting
Power Mirrors non functional
The error codes interpreted as the following:
P1516 – Throttle Actuator Control (TAC) module – Throttle Actuator Position Performance
P1682- Driver 5 Line 2 (voltage difference between the two ignition 1 voltage circuits)
P2176- Throttle Actuator Control System Idle Position Not Learned
U0101 – Lost Communication with the TCM
I found several TSB’s on these codes:
08-07-30-021e: Deals with error code U0101. This was my first attempt to fix the problem.
Check the 16 way Electrical connector on top of the trans-axle. (Suspected corrosion or backed out terminal, etc.). And it did for about 15 minutes. Car drove normally, plenty of power, etc. After test drive, I rechecked that the codes were clear, and they were. Next time I started the car- codes were back.
06-06-04-007: Delineates the problem may be due to Low Battery Voltage.
My Battery was about 5 years old, and I replaced it, but this did not resolve my symptoms.
I found a post on the gm-truck forums where it a man fixed his P1516 error code as he called this a grounding issue. So, I did more research and found diagrams of grounding points on C6 Corvettes.
There are 13 I believe. I also found another post about a 98 coupe with similar codes that had corrosion on his grounding connectors. My next attempt to resolve this issue was to find and clean my grounding connectors. I cleaned G101, G102, G104, G105, and G106). G107 turned out to be a tough mother- could not get a wrench on it (lying upside down and tight fit with exhaust converter in way). I also cleaned the battery grounds. All this did not resolve the issue.
I found additional posts on the TAC and TCB:
I checked the wires leading to the TAC, TCB, and wiggle tested them, looking for bad connectors, loose terminals, etc. I did not find any obvious loose terminals, broken wires, or bad connectors. Check terminals for corrosion, bad connector, broken wires (may be up to four inches away from connector), and/or metal ring terminal crimped over plastic and no contact or little contact to bare wire.
Continuing the trouble shooting process, I also found posts where the diode in the fuse box -- black with a [1.0] marked on it closest to the front of the car was changed out and this fixed the problem.
Also, others had issues with mini relays- specifically #44(Powertrain ignition 1) or #43(Crank). You can pick these up rather inexpensively at an auto parts store and swap them out to see if this resolves the problem. I ended up returning the relay to the auto store – saved about $20 doing that.
Back to the drawing board: Somewhere in my research I came across a DTC on P1682, and thought to try and find DTC’s for P1516 and P1682. Not easy to locate but, through persistence I was able to find them. Not having the expertise or equipment to trouble-shoot these codes – I read them and found something interesting:
All these DTC’s all lead (no pun intended) to similar trouble spots:
DTC P1682
-Test for shorted terminals and poor connections at the ECM wire harness electrical connector.
-High resistance or open in the ignition 1 voltage circuit between under-hood fuse block & ECM.
DTC P2176
-Test ETC ignition 1 voltage circuit for short to ground
-Test Motor control 1 circuit for short to ground
-Poor Connection or terminal tension at Throttle Body Connector
DTC P1516
-Test TAC motor Control 1 & 2 Circuits for short to ground
-Test ETC ignition 1 voltage circuit for short to ground
-Poor connection or terminal tension at TBC.
- Poor Connection or terminal tension at the PCM
- Open or high resistance in the ETC ignition 1 voltage Circuit
The very last step of these DTC’s is to replace the TCM, TBA, or PCM, if none of the shorts, open, or high resistance, poor connections are found.
Yet, replacing the TCM is often the first diagnosis from the repair facility.
Trouble shooting these DTC’s being beyond my ability to do and I dreaded taking the car to the dealership- knowing that they would tell me I would need to replace the TCM. But I had no choice at this point. The first diagnosis, from the dealer was to replace the TCM. So I asked if the Tech actually ran the DTC’s for these error codes. The answer was no. My response was the problem was intermittent, and most likely electrical and not a bad TCM, and for the tech to keep looking.
Located on the inside of the engine compartment behind the battery near the fender wall there is a blue connector box a little bigger than the size of a deck of cards. Inside the connector box the ground connector had become unseated and was pushed further back than the rest of the connectors.
This was my gremlin… The tech showed me the picture he took of the connector when he discovered it. The connector was reseated and every single condition of the car was remediated immediately.
This post is the culmination of two weeks-worth of DIY research and trouble-shooting (what I was capable of doing anyway). I am posting this as a way of paying it forward to those who have similar error code issues... and as a thank you to those I was able to infer this information from.
Hope it helps somebody save some aggravation, time, money, and misdiagnosis. I know it did for me…
I had all these error codes come up on my 2005 C6. I started driving car in April 2016 with no problems until just this September.
Doing research on Corvette Forum and other locations on the internet I found many horror stories and also how elusive these error codes can be. Specifically many people replacing their TCM, batteries, and a host of other parts without a real resolution to the problem.
Here are all the symptoms the C6 was displaying:
Check engine light steady on
Security light steady on
DIC- displaying Service traction System
DIC – Not reading transmission fluid temperature
Engine dieseling at shutoff for up to 10 seconds
No power at the low end
Heads up display not functioning properly
Instrument cluster not working
Rough idle upon starting
Power Mirrors non functional
The error codes interpreted as the following:
P1516 – Throttle Actuator Control (TAC) module – Throttle Actuator Position Performance
P1682- Driver 5 Line 2 (voltage difference between the two ignition 1 voltage circuits)
P2176- Throttle Actuator Control System Idle Position Not Learned
U0101 – Lost Communication with the TCM
I found several TSB’s on these codes:
08-07-30-021e: Deals with error code U0101. This was my first attempt to fix the problem.
Check the 16 way Electrical connector on top of the trans-axle. (Suspected corrosion or backed out terminal, etc.). And it did for about 15 minutes. Car drove normally, plenty of power, etc. After test drive, I rechecked that the codes were clear, and they were. Next time I started the car- codes were back.
06-06-04-007: Delineates the problem may be due to Low Battery Voltage.
My Battery was about 5 years old, and I replaced it, but this did not resolve my symptoms.
I found a post on the gm-truck forums where it a man fixed his P1516 error code as he called this a grounding issue. So, I did more research and found diagrams of grounding points on C6 Corvettes.
There are 13 I believe. I also found another post about a 98 coupe with similar codes that had corrosion on his grounding connectors. My next attempt to resolve this issue was to find and clean my grounding connectors. I cleaned G101, G102, G104, G105, and G106). G107 turned out to be a tough mother- could not get a wrench on it (lying upside down and tight fit with exhaust converter in way). I also cleaned the battery grounds. All this did not resolve the issue.
I found additional posts on the TAC and TCB:
I checked the wires leading to the TAC, TCB, and wiggle tested them, looking for bad connectors, loose terminals, etc. I did not find any obvious loose terminals, broken wires, or bad connectors. Check terminals for corrosion, bad connector, broken wires (may be up to four inches away from connector), and/or metal ring terminal crimped over plastic and no contact or little contact to bare wire.
Continuing the trouble shooting process, I also found posts where the diode in the fuse box -- black with a [1.0] marked on it closest to the front of the car was changed out and this fixed the problem.
Also, others had issues with mini relays- specifically #44(Powertrain ignition 1) or #43(Crank). You can pick these up rather inexpensively at an auto parts store and swap them out to see if this resolves the problem. I ended up returning the relay to the auto store – saved about $20 doing that.
Back to the drawing board: Somewhere in my research I came across a DTC on P1682, and thought to try and find DTC’s for P1516 and P1682. Not easy to locate but, through persistence I was able to find them. Not having the expertise or equipment to trouble-shoot these codes – I read them and found something interesting:
All these DTC’s all lead (no pun intended) to similar trouble spots:
DTC P1682
-Test for shorted terminals and poor connections at the ECM wire harness electrical connector.
-High resistance or open in the ignition 1 voltage circuit between under-hood fuse block & ECM.
DTC P2176
-Test ETC ignition 1 voltage circuit for short to ground
-Test Motor control 1 circuit for short to ground
-Poor Connection or terminal tension at Throttle Body Connector
DTC P1516
-Test TAC motor Control 1 & 2 Circuits for short to ground
-Test ETC ignition 1 voltage circuit for short to ground
-Poor connection or terminal tension at TBC.
- Poor Connection or terminal tension at the PCM
- Open or high resistance in the ETC ignition 1 voltage Circuit
The very last step of these DTC’s is to replace the TCM, TBA, or PCM, if none of the shorts, open, or high resistance, poor connections are found.
Yet, replacing the TCM is often the first diagnosis from the repair facility.
Trouble shooting these DTC’s being beyond my ability to do and I dreaded taking the car to the dealership- knowing that they would tell me I would need to replace the TCM. But I had no choice at this point. The first diagnosis, from the dealer was to replace the TCM. So I asked if the Tech actually ran the DTC’s for these error codes. The answer was no. My response was the problem was intermittent, and most likely electrical and not a bad TCM, and for the tech to keep looking.
Located on the inside of the engine compartment behind the battery near the fender wall there is a blue connector box a little bigger than the size of a deck of cards. Inside the connector box the ground connector had become unseated and was pushed further back than the rest of the connectors.
This was my gremlin… The tech showed me the picture he took of the connector when he discovered it. The connector was reseated and every single condition of the car was remediated immediately.
This post is the culmination of two weeks-worth of DIY research and trouble-shooting (what I was capable of doing anyway). I am posting this as a way of paying it forward to those who have similar error code issues... and as a thank you to those I was able to infer this information from.
Hope it helps somebody save some aggravation, time, money, and misdiagnosis. I know it did for me…
10-03-2016, 02:54 PM
#5
Instructor
I'll give it a try
Error Codes P1516, P1682, P2176, and U0101.
I had all these error codes come up on my 2005 C6. I started driving car in April 2016 with no problems until just this September.
Doing research on Corvette Forum and other locations on the internet I found many horror stories and also how elusive these error codes can be. Specifically many people replacing their TCM, batteries, and a host of other parts without a real resolution to the problem.
Here are all the symptoms the C6 was displaying:
Check engine light steady on
Security light steady on
DIC- displaying Service traction System
DIC – Not reading transmission fluid temperature
Engine dieseling at shutoff for up to 10 seconds
No power at the low end
Heads up display not functioning properly
Instrument cluster not working
Rough idle upon starting
Power Mirrors non functional
The error codes interpreted as the following:
P1516 – Throttle Actuator Control (TAC) module – Throttle Actuator Position Performance
P1682- Driver 5 Line 2 (voltage difference between the two ignition 1 voltage circuits)
P2176- Throttle Actuator Control System Idle Position Not Learned
U0101 – Lost Communication with the TCM
I found several TSB’s on these codes:
08-07-30-021e: Deals with error code U0101. This was my first attempt to fix the problem.
Check the 16 way Electrical connector on top of the trans-axle. (Suspected corrosion or backed out terminal, etc.). And it did for about 15 minutes. Car drove normally, plenty of power, etc. After test drive, I rechecked that the codes were clear, and they were. Next time I started the car- codes were back.
06-06-04-007: Delineates the problem may be due to Low Battery Voltage.
My Battery was about 5 years old, and I replaced it, but this did not resolve my symptoms.
I found a post on the gm-truck forums where it a man fixed his P1516 error code as he called this a grounding issue. So, I did more research and found diagrams of grounding points on C6 Corvettes.
There are 13 I believe. I also found another post about a 98 coupe with similar codes that had corrosion on his grounding connectors. My next attempt to resolve this issue was to find and clean my grounding connectors. I cleaned G101, G102, G104, G105, and G106). G107 turned out to be a tough mother- could not get a wrench on it (lying upside down and tight fit with exhaust converter in way). I also cleaned the battery grounds. All this did not resolve the issue.
I found additional posts on the TAC and TCB:
I checked the wires leading to the TAC, TCB, and wiggle tested them, looking for bad connectors, loose terminals, etc. I did not find any obvious loose terminals, broken wires, or bad connectors. Check terminals for corrosion, bad connector, broken wires (may be up to four inches away from connector), and/or metal ring terminal crimped over plastic and no contact or little contact to bare wire.
Continuing the trouble shooting process, I also found posts where the diode in the fuse box -- black with a [1.0] marked on it closest to the front of the car was changed out and this fixed the problem.
Also, others had issues with mini relays- specifically #44(Powertrain ignition 1) or #43(Crank). You can pick these up rather inexpensively at an auto parts store and swap them out to see if this resolves the problem. I ended up returning the relay to the auto store – saved about $20 doing that.
Back to the drawing board: Somewhere in my research I came across a DTC on P1682, and thought to try and find DTC’s for P1516 and P1682. Not easy to locate but, through persistence I was able to find them. Not having the expertise or equipment to trouble-shoot these codes – I read them and found something interesting:
All these DTC’s all lead (no pun intended) to similar trouble spots:
DTC P1682
-Test for shorted terminals and poor connections at the ECM wire harness electrical connector.
-High resistance or open in the ignition 1 voltage circuit between under-hood fuse block & ECM.
DTC P2176
-Test ETC ignition 1 voltage circuit for short to ground
-Test Motor control 1 circuit for short to ground
-Poor Connection or terminal tension at Throttle Body Connector
DTC P1516
-Test TAC motor Control 1 & 2 Circuits for short to ground
-Test ETC ignition 1 voltage circuit for short to ground
-Poor connection or terminal tension at TBC.
- Poor Connection or terminal tension at the PCM
- Open or high resistance in the ETC ignition 1 voltage Circuit
The very last step of these DTC’s is to replace the TCM, TBA, or PCM, if none of the shorts, open, or high resistance, poor connections are found.
Yet, replacing the TCM is often the first diagnosis from the repair facility.
Trouble shooting these DTC’s being beyond my ability to do and I dreaded taking the car to the dealership- knowing that they would tell me I would need to replace the TCM. But I had no choice at this point. The first diagnosis, from the dealer was to replace the TCM. So I asked if the Tech actually ran the DTC’s for these error codes. The answer was no. My response was the problem was intermittent, and most likely electrical and not a bad TCM, and for the tech to keep looking.
Located on the inside of the engine compartment behind the battery near the fender wall there is a blue connector box a little bigger than the size of a deck of cards. Inside the connector box the ground connector had become unseated and was pushed further back than the rest of the connectors.
This was my gremlin… The tech showed me the picture he took of the connector when he discovered it. The connector was reseated and every single condition of the car was remediated immediately.
This post is the culmination of two weeks-worth of DIY research and trouble-shooting (what I was capable of doing anyway). I am posting this as a way of paying it forward to those who have similar error code issues... and as a thank you to those I was able to infer this information from.
Hope it helps somebody save some aggravation, time, money, and misdiagnosis. I know it did for me…
I had all these error codes come up on my 2005 C6. I started driving car in April 2016 with no problems until just this September.
Doing research on Corvette Forum and other locations on the internet I found many horror stories and also how elusive these error codes can be. Specifically many people replacing their TCM, batteries, and a host of other parts without a real resolution to the problem.
Here are all the symptoms the C6 was displaying:
Check engine light steady on
Security light steady on
DIC- displaying Service traction System
DIC – Not reading transmission fluid temperature
Engine dieseling at shutoff for up to 10 seconds
No power at the low end
Heads up display not functioning properly
Instrument cluster not working
Rough idle upon starting
Power Mirrors non functional
The error codes interpreted as the following:
P1516 – Throttle Actuator Control (TAC) module – Throttle Actuator Position Performance
P1682- Driver 5 Line 2 (voltage difference between the two ignition 1 voltage circuits)
P2176- Throttle Actuator Control System Idle Position Not Learned
U0101 – Lost Communication with the TCM
I found several TSB’s on these codes:
08-07-30-021e: Deals with error code U0101. This was my first attempt to fix the problem.
Check the 16 way Electrical connector on top of the trans-axle. (Suspected corrosion or backed out terminal, etc.). And it did for about 15 minutes. Car drove normally, plenty of power, etc. After test drive, I rechecked that the codes were clear, and they were. Next time I started the car- codes were back.
06-06-04-007: Delineates the problem may be due to Low Battery Voltage.
My Battery was about 5 years old, and I replaced it, but this did not resolve my symptoms.
I found a post on the gm-truck forums where it a man fixed his P1516 error code as he called this a grounding issue. So, I did more research and found diagrams of grounding points on C6 Corvettes.
There are 13 I believe. I also found another post about a 98 coupe with similar codes that had corrosion on his grounding connectors. My next attempt to resolve this issue was to find and clean my grounding connectors. I cleaned G101, G102, G104, G105, and G106). G107 turned out to be a tough mother- could not get a wrench on it (lying upside down and tight fit with exhaust converter in way). I also cleaned the battery grounds. All this did not resolve the issue.
I found additional posts on the TAC and TCB:
I checked the wires leading to the TAC, TCB, and wiggle tested them, looking for bad connectors, loose terminals, etc. I did not find any obvious loose terminals, broken wires, or bad connectors. Check terminals for corrosion, bad connector, broken wires (may be up to four inches away from connector), and/or metal ring terminal crimped over plastic and no contact or little contact to bare wire.
Continuing the trouble shooting process, I also found posts where the diode in the fuse box -- black with a [1.0] marked on it closest to the front of the car was changed out and this fixed the problem.
Also, others had issues with mini relays- specifically #44(Powertrain ignition 1) or #43(Crank). You can pick these up rather inexpensively at an auto parts store and swap them out to see if this resolves the problem. I ended up returning the relay to the auto store – saved about $20 doing that.
Back to the drawing board: Somewhere in my research I came across a DTC on P1682, and thought to try and find DTC’s for P1516 and P1682. Not easy to locate but, through persistence I was able to find them. Not having the expertise or equipment to trouble-shoot these codes – I read them and found something interesting:
All these DTC’s all lead (no pun intended) to similar trouble spots:
DTC P1682
-Test for shorted terminals and poor connections at the ECM wire harness electrical connector.
-High resistance or open in the ignition 1 voltage circuit between under-hood fuse block & ECM.
DTC P2176
-Test ETC ignition 1 voltage circuit for short to ground
-Test Motor control 1 circuit for short to ground
-Poor Connection or terminal tension at Throttle Body Connector
DTC P1516
-Test TAC motor Control 1 & 2 Circuits for short to ground
-Test ETC ignition 1 voltage circuit for short to ground
-Poor connection or terminal tension at TBC.
- Poor Connection or terminal tension at the PCM
- Open or high resistance in the ETC ignition 1 voltage Circuit
The very last step of these DTC’s is to replace the TCM, TBA, or PCM, if none of the shorts, open, or high resistance, poor connections are found.
Yet, replacing the TCM is often the first diagnosis from the repair facility.
Trouble shooting these DTC’s being beyond my ability to do and I dreaded taking the car to the dealership- knowing that they would tell me I would need to replace the TCM. But I had no choice at this point. The first diagnosis, from the dealer was to replace the TCM. So I asked if the Tech actually ran the DTC’s for these error codes. The answer was no. My response was the problem was intermittent, and most likely electrical and not a bad TCM, and for the tech to keep looking.
Located on the inside of the engine compartment behind the battery near the fender wall there is a blue connector box a little bigger than the size of a deck of cards. Inside the connector box the ground connector had become unseated and was pushed further back than the rest of the connectors.
This was my gremlin… The tech showed me the picture he took of the connector when he discovered it. The connector was reseated and every single condition of the car was remediated immediately.
This post is the culmination of two weeks-worth of DIY research and trouble-shooting (what I was capable of doing anyway). I am posting this as a way of paying it forward to those who have similar error code issues... and as a thank you to those I was able to infer this information from.
Hope it helps somebody save some aggravation, time, money, and misdiagnosis. I know it did for me…
10-04-2016, 05:40 PM
#6
Instructor
Ive been chasing some intermittent codes for weeks now. My main one is P0601 that is a checksum error in the Transmission Control Module. Along with that comes many other deeper codes at which point the engine dies. This is not a comfortable feeling at 70 mph. It's weird because the TCM is inside an auto transmission and mine is a manual transmission. I've tried cleaning many grounds and connectors to no avail. Today I just peeked at the connector behind the battery. I just jiggled it around to be sure it was tight but I didn't really inspect it. After driving for about an hour with no problem, I started the car again and it was fine but the check engine light came on. When I got home it was the same P0601 but it did not stall. Based on your experience I'll pull that connector apart and take a really close look and keep my fingers crossed. I'll let you know how it goes.
Thanks to all the members.
10-05-2016, 05:48 PM
#7
Instructor
Today I cleaned the 2 large connectors behind the battery and the 2 plugs connected to the computer inside the passenger side wheel well behind the front wheel. I think this the ECM? Anyway, I started the car and the Check Engine light went out by itself. So far, so good. The only issue was the DIC is showing 3 tires with 0 pressure and one was normal. Will this reset itself or do I need to reset it? Also, the idle was a little rough but I think this should smooth out.
Thanks to all the members.
Thanks to all the members.
10-07-2016, 06:09 PM
#9
Instructor
10-07-2016, 06:55 PM
#10
Team Owner
Usually when there are many many codes and issues, it is a communication issue between modules with likely a connector having problems. Dealers usually start trying to diagnose and deal with one code/problem at a time which usually ends up wasting a ton of time and customer money. While it is not unheard of to have a solid state module go bad, it is far far more likely that a connection between modules is at fault.
10-08-2016, 07:23 PM
#11
Instructor
Usually when there are many many codes and issues, it is a communication issue between modules with likely a connector having problems. Dealers usually start trying to diagnose and deal with one code/problem at a time which usually ends up wasting a ton of time and customer money. While it is not unheard of to have a solid state module go bad, it is far far more likely that a connection between modules is at fault.
11-02-2016, 09:29 AM
#12
Were you able to find anything? My vette was running great after the electrical connector problem was finally located and repaired. (all those codes and intermittent problems went away).
But,I hit a bump on the highway the yesterday and the vette went into low power mode- basically stalled going 60 mph on a busy commute to work. Luckily I was in right hand lane and able to pull over and not get creamed. Had to turn off engine and was able to restart. Vette stalled a couple of times while I was waiting on side of road to pull back out into traffic. Finally got going only to stall at an intersection. Left work after monring rush hour to get vette back home. Only stalled twice on way home.
After fixing the loose connector from before, I bought a Innova 3100i diagnostic tool and plugged that in the vette after this experience. Got error code p0601. Also got DTC P0001 - which I am investigating now.
P0001 is Fuel Volume Regulator Control Circuit "Open". The diagnostic tool also was tripping on 025- Oxygen Sensor Monitor, CAT - Catalyst Monitor, EVA- EVAP System Monitor.
I am in the process of registering the INNOVA to the website link to find common fixes for this.
In the meantime, what I am finding out in Goolgeland for P0001 is to check the circuit running from the Engine Computer (ECM) to the Fuel Pressure Regulator on your Fuel Injection Rail. Also, Fuel Volume Regulator (FVR) Solenoid. FVR wiring/harness electrical problem (wiring, short, etc).
Try:
www.obd-codes.com/p0001 and
autoservicecosts.com/obd2-codes/p0001/ for more info.
I have no idea where all this stuff is located so, I am going to have to hunt them down...and learn as I go...
But,I hit a bump on the highway the yesterday and the vette went into low power mode- basically stalled going 60 mph on a busy commute to work. Luckily I was in right hand lane and able to pull over and not get creamed. Had to turn off engine and was able to restart. Vette stalled a couple of times while I was waiting on side of road to pull back out into traffic. Finally got going only to stall at an intersection. Left work after monring rush hour to get vette back home. Only stalled twice on way home.
After fixing the loose connector from before, I bought a Innova 3100i diagnostic tool and plugged that in the vette after this experience. Got error code p0601. Also got DTC P0001 - which I am investigating now.
P0001 is Fuel Volume Regulator Control Circuit "Open". The diagnostic tool also was tripping on 025- Oxygen Sensor Monitor, CAT - Catalyst Monitor, EVA- EVAP System Monitor.
I am in the process of registering the INNOVA to the website link to find common fixes for this.
In the meantime, what I am finding out in Goolgeland for P0001 is to check the circuit running from the Engine Computer (ECM) to the Fuel Pressure Regulator on your Fuel Injection Rail. Also, Fuel Volume Regulator (FVR) Solenoid. FVR wiring/harness electrical problem (wiring, short, etc).
Try:
www.obd-codes.com/p0001 and
autoservicecosts.com/obd2-codes/p0001/ for more info.
I have no idea where all this stuff is located so, I am going to have to hunt them down...and learn as I go...
11-03-2016, 07:43 PM
#13
Instructor
Man this is frustrating! I thought I was home free. The car hasn't been stalling but I was runnsome errands and parked for about 10 minutes. When i got back in the and tried to start the car I noticed the green start button was not lit. I pressed it and got nothing. I then pressed the lower part of the button and I could relays clicking all over the place. I waited about 2 minutes and the car started up and I was on my way but the Check Engine light was on again. When I got home I plugged in my scanner and it was the same P0601 code but no other codes like other times. When I started it up the next day it was fine and the check engine light was out by itself even though I didn't clear the codes. I'm starting to think this is heat related since it was pretty hot out and I had been doing a lot of stop and go.
The next thing I did was clean and retighten the wires at the starter solenoid. They weren't loose but they weren't that tight either.
Who knows? I'll just wait and see again.
The next thing I did was clean and retighten the wires at the starter solenoid. They weren't loose but they weren't that tight either.
Who knows? I'll just wait and see again.
11-08-2016, 01:03 PM
#14
The PCM may turn off the MIL (check engine light) if the monitor that set the DTC runs and passes on three consecutive trips.
The monitors may run continuously (engine running, idling does not satisfy as engine running)
or non-continuous (enabling criteria must be met before PCM initiaties the test)
Continuous Monitors
Misfire
Fuel System
Comprehensive Component
Non-Continuous Monitors
Non-continuous monitors for spark ignition cars (gasoline engines)
Spark ignition vehicles (Gas)
Catalyst (CAT)
Heated Catalyst
Evaporative (EVAP) System
Secondary Air System
Oxygen (O2) Sensor
Oxygen Sensor Heater
EGR (Exhaust Gas Recirculation) and/or VVT System
Once the MIL is turned off by the PCM, DTC and Freeze Frame data are stored in the PCM memory for a predetermined number of warm up cycles.
A warm up is counted by the PCM when the engine is started, coolant temp reaches 160F and there is an increase in coolant temp of 40F.
A trip is defined as a start-to-run, drive cycle that provides enabling criteria for a monitor (I/M system monitors- like O2 sensor, misfire, fuel sysyem, etc.) to run, and engine shutdown. Since enabling criteria are different for the different monitors, the definition of a trip depends on the monitor.
A drive cycle is completed when the vehicle is driven and satifies the enabling criteria for all the individual monitors. If all monitors run successfully, the readiness status display will mark them complete/done depending on the scan tool.
A drive cycle is more than just driving the car down the road. There are specific conditions underwhich the car must be subjected for it to be considered having been put thru a drive cycle. Example:
1) Cold Start (coolant below 122F)
2) Warm engine for 5-8 minutes
3) Accelerate to 55mph at 1/2 throttle with a/c off
4) steady cruise at 55mph for 3 min
5) Decelerate to 20 mph clutch out and no brake (coasting??)
6) 3/4 throttle acceleration to 60 mph
7) Steady cruise at 60 mph for 5 min
8) Decelerate clutch out and no brake
end of test. (12-15 minutes to complete the test)
A drive cycle like this would appear to engage all monitors to run
and each monitor to complete its test.
Supposedly the drive cycle like the one above is in the car's respective driver's manual.
I guess you could try and locate it your driver's manual and perform 3 drive cycles, then rehook up your code reader and see if the MIL stays
off and check the status of the I/M monitors (if your code reader is capable of doing that).
Note: As soon as the PCM tells the MIL to turn off after three good trips, another counter starts... Each time the PCM sees a warm-up completed it adds 'one' to the counter. When the warm up counter gets to 40, the DTC will be erased (If the fault has not been repeated during that time). Fuel and Misfire monitors may require 80 warm up cycles.
One more thing- unacceptable emissions-not driveability - is the major concern of the OBD II monitoring system, although they may be related. OBD is concerned with emissons first, driveability second.
All the OBD II system cares about is that its surveillance of monitored systems has turned up edvidence of unacceptable emissions. It wants the problem fixed or it will turn the MIL back ON!
That however does not preclude a shorted wire, bad connector, etc from sending the system into a WTF frenzy and the PCM cant tell an input voltage from its hind quarters and shut the car down at 60 mph on the highway... or saying I need a new PCM when I really don't...
The monitors may run continuously (engine running, idling does not satisfy as engine running)
or non-continuous (enabling criteria must be met before PCM initiaties the test)
Continuous Monitors
Misfire
Fuel System
Comprehensive Component
Non-Continuous Monitors
Non-continuous monitors for spark ignition cars (gasoline engines)
Spark ignition vehicles (Gas)
Catalyst (CAT)
Heated Catalyst
Evaporative (EVAP) System
Secondary Air System
Oxygen (O2) Sensor
Oxygen Sensor Heater
EGR (Exhaust Gas Recirculation) and/or VVT System
Once the MIL is turned off by the PCM, DTC and Freeze Frame data are stored in the PCM memory for a predetermined number of warm up cycles.
A warm up is counted by the PCM when the engine is started, coolant temp reaches 160F and there is an increase in coolant temp of 40F.
A trip is defined as a start-to-run, drive cycle that provides enabling criteria for a monitor (I/M system monitors- like O2 sensor, misfire, fuel sysyem, etc.) to run, and engine shutdown. Since enabling criteria are different for the different monitors, the definition of a trip depends on the monitor.
A drive cycle is completed when the vehicle is driven and satifies the enabling criteria for all the individual monitors. If all monitors run successfully, the readiness status display will mark them complete/done depending on the scan tool.
A drive cycle is more than just driving the car down the road. There are specific conditions underwhich the car must be subjected for it to be considered having been put thru a drive cycle. Example:
1) Cold Start (coolant below 122F)
2) Warm engine for 5-8 minutes
3) Accelerate to 55mph at 1/2 throttle with a/c off
4) steady cruise at 55mph for 3 min
5) Decelerate to 20 mph clutch out and no brake (coasting??)
6) 3/4 throttle acceleration to 60 mph
7) Steady cruise at 60 mph for 5 min
8) Decelerate clutch out and no brake
end of test. (12-15 minutes to complete the test)
A drive cycle like this would appear to engage all monitors to run
and each monitor to complete its test.
Supposedly the drive cycle like the one above is in the car's respective driver's manual.
I guess you could try and locate it your driver's manual and perform 3 drive cycles, then rehook up your code reader and see if the MIL stays
off and check the status of the I/M monitors (if your code reader is capable of doing that).
Note: As soon as the PCM tells the MIL to turn off after three good trips, another counter starts... Each time the PCM sees a warm-up completed it adds 'one' to the counter. When the warm up counter gets to 40, the DTC will be erased (If the fault has not been repeated during that time). Fuel and Misfire monitors may require 80 warm up cycles.
One more thing- unacceptable emissions-not driveability - is the major concern of the OBD II monitoring system, although they may be related. OBD is concerned with emissons first, driveability second.
All the OBD II system cares about is that its surveillance of monitored systems has turned up edvidence of unacceptable emissions. It wants the problem fixed or it will turn the MIL back ON!
That however does not preclude a shorted wire, bad connector, etc from sending the system into a WTF frenzy and the PCM cant tell an input voltage from its hind quarters and shut the car down at 60 mph on the highway... or saying I need a new PCM when I really don't...
The following users liked this post:
cpetruzzi (11-08-2016)
11-09-2016, 08:49 PM
#15
Instructor
No start P0601 & Freeze Frame
This was a couple of weeks ago when it wouldn't start. Does anything look out of norm? After about 1 minute and it started up and has been fine since then. MIL light went out on it's own.
Trouble Codes
P0601 $07E8
Internal Control Module Memory Check Sum Error
Freeze Frame
DTC that caused required freeze P0601
frame data storage
Fuel system 1 status CL
Fuel System 2 status CL
Calculated Load Value 24.7 %
Engine Coolant Temperature 189 °F
Short Term Fuel Trim -Bank 1 -2.3 %
Long Term Fuel Trim - Bank 1 10.2 %
Short Term Fuel Trim -Bank 2 -5.5 %
Long Term Fuel Trim - Bank 2 7.0 %
Intake Manifold Absolute Pressure 5.2 psi
Engine RPM 708 rpm
Vehicle Speed Sensor 0 mph
Ignition Timing Advance for #1 5.5 °
Cylinder
Intake Air Temperature 113 °F
Air Flow Rate from Mass Air Flow 0.02 lb/s
Sensor
Absolute Throttle Position 16.5 %
Time Since Engine Start 1534 sec
Commanded Evaporative Purge 20.8 %
Fuel Level Input 61.2 %
Number of warm-ups since 5
diagnostic trouble codes cleared
Distance since diagnostic trouble 51 miles
codes cleared
Evap System Vapor Pressure -0.492 inH2o
Barometric Pressure 14.5 psi
Catalyst Temperature Bank 1078 °F
1,Sensor 1
Catalyst Temperature Bank 1132 °F
2,Sensor 1
Control module voltage 13.521 V
Absolute Load Value 18.0 %
Commanded Equivalence Ratio 0.999
Relative Throttle Position 5.9 %
Ambient air temperature 82 °F
Absolute Throttle Position B 15.7 %
Accelerator Pedal Position D 20.8 %
Accelerator Pedal Position E 10.2 %
Commanded Throttle Actuator 7.5 %
Control
Trouble Codes
P0601 $07E8
Internal Control Module Memory Check Sum Error
Freeze Frame
DTC that caused required freeze P0601
frame data storage
Fuel system 1 status CL
Fuel System 2 status CL
Calculated Load Value 24.7 %
Engine Coolant Temperature 189 °F
Short Term Fuel Trim -Bank 1 -2.3 %
Long Term Fuel Trim - Bank 1 10.2 %
Short Term Fuel Trim -Bank 2 -5.5 %
Long Term Fuel Trim - Bank 2 7.0 %
Intake Manifold Absolute Pressure 5.2 psi
Engine RPM 708 rpm
Vehicle Speed Sensor 0 mph
Ignition Timing Advance for #1 5.5 °
Cylinder
Intake Air Temperature 113 °F
Air Flow Rate from Mass Air Flow 0.02 lb/s
Sensor
Absolute Throttle Position 16.5 %
Time Since Engine Start 1534 sec
Commanded Evaporative Purge 20.8 %
Fuel Level Input 61.2 %
Number of warm-ups since 5
diagnostic trouble codes cleared
Distance since diagnostic trouble 51 miles
codes cleared
Evap System Vapor Pressure -0.492 inH2o
Barometric Pressure 14.5 psi
Catalyst Temperature Bank 1078 °F
1,Sensor 1
Catalyst Temperature Bank 1132 °F
2,Sensor 1
Control module voltage 13.521 V
Absolute Load Value 18.0 %
Commanded Equivalence Ratio 0.999
Relative Throttle Position 5.9 %
Ambient air temperature 82 °F
Absolute Throttle Position B 15.7 %
Accelerator Pedal Position D 20.8 %
Accelerator Pedal Position E 10.2 %
Commanded Throttle Actuator 7.5 %
Control
11-16-2016, 01:13 PM
#16
Here's some of what I have learned so far::
First off you get a lot a good data from your code reader... Would you mind telling me which one you have?? I don't get all that data from the current one I am using.
The $07e8 after the P0601 is just a number represented in the hexadecimal number system which is based on 16. Instead of the Decimal number system base of 10.
In Binary 07e8 is written as 0000 0111 1110 1000 or in the decimal number system it is the number 2024.
Not really going to help us at our level. So don’t worry about the $07E8.
Your Fuel status going into closed loop (is what is supposed to happen). Basically, the O2 sensors in the exhaust start producing a signal, the PCM switches into the closed-loop mode. (Open loop being the car is running on stored or preset data stored in the PCM so the car runs). Entering closed loop the car is now adjusting fuel delivery, spark advance, and idle speed to meet various operating conditions.
Another way to think of it would be... Open loop is like a carburetor choke... closed loop the car has warmed up and is using real time sensor data to run the car.
I don’t know what calculated load value means yet. Still learning all this stuff.
Obviously your car had been running temp as operating temp was 189F.
Short term and long term fuel trim:
Short term fuel trim (STFT) adjusts the injector pulse width to keep the system in closed loop. The system starts at a base figure and goes rich or lean from that point. (No idea what base figure is -- probably varies from engine to engine). If engine is right on- then corrections should be fairly small. STFT data is erased when ignition is turned off.
LTFT- is a shift in the base figure. If short term corrections are repeatedly pegged at their limits, then long term memory shifts. The starting point for STFT moves closer to the actual corrections that are needed. The system must be in closed loop to store changes in LTFT corrections. LTFT data are stored in memory even after ignition is turned off.
PCM uses STFT and LTFT factors to calculate total fuel correction to maintain closed loop. If system gets too lean or rich, fault data will be stored in PCM as a MATURING fault.
If the limit is exceeded on two consecutive trips the fault will Mature and then MIL comes on.
This goes back to knowing how the whole OBD II system works and when it activates the MIL. One fail is stored in PCM as a Maturing fault. Two fails on the second consecutive trip: the PCM takes the maturing fault and now says you’re mature... and turns on the dreaded MIL (Check engine light).
Now go back and refresh your memory on what a 'trip' and 'drive cycle' are...
It can get really complex, but most of the monitors in the OBD II system are two trip failures. So if you drive your vette in such a way that the car does not complete a drive cycle... (Say running a quick errand) the PCM will not test all its emissions tests.
So if you have a 1 trip fail stored in the PCM (as a Maturing fault), and on your next drive the car doesn't initiate that specific test, the PCM won’t be able to fail it a second time and turn on the MIL.
Here's my take... You never want to manually clear error codes from a PCM. The PCM will turn them off after 3 consecutive trips with no fails. Then erase them from PCM data after 40 warm up cycles... You should never let a car dealership clear the error codes from the PCM either...
You could have a 1 trip fault stored in the PCM for months if you only drive your vette in nice weather, non-rainy days, and store in winter, etc. And when you do finally drive it... If it does not complete a drive cycle then the fault does not mature- No MIL.
See the problem here... Erasing codes does not allow the PCM to check the system on its own and turn off the MIL after 3 good drive cycles...You could potentially have a 1 trip fail stored for several months... and say after you got the car fixed at a dealer and they clear the codes... how long before you drive it next time thru a complete drive cycle and the PCM finally takes that maturing code and makes it mature; and turn on the MIL--- or has two go thru two trips again before the MIL is turned on because the 1 maturing code was erased.
If your car is fixed for 2 trip fault MIL problem A, and problem B is only at one fail-- a maturing fault, and the codes are cleared, the stored 1 trip fail is gone… and will now take two more drive cycles to fail and turn the MIL back on for problem B.
Back to your code reads:
Intake Manifold Absolute Pressure- Unsure what a good reading on this is.
Ignition Timing Advance- ditto
Air Flow Rate from Mass Air Flow- ditto
Absolute Throttle Position – ditto
Commanded EVAP Purge – ditto- but since you have reading seems the EVAP purge test was completed.
Fuel Level Input- ditto
Number of warm-ups since 5
diagnostic trouble codes cleared
Distance since diagnostic trouble 51 miles
codes cleared
These are two good readings… If the MIL went out by itself like you said, then it appears you went thru 3 drive cycles and the PCM found no faults and turned out the MIL itself. To me this is being verified by the 5 warm up cycles count going on shown above… This counter will increase and eventually the PCM will erase any stored DTC’s
EVAP System Vapor Pressure - Unsure what a good reading on this is, but seems the EVAP purge test was completed
Catalyst Temperature Bank 1078 °F
1,Sensor 1
Catalyst Temperature Bank 1132 °F
2,Sensor 1
Control module voltage 13.521 V
Absolute Load Value 18.0 %
Commanded Equivalence Ratio 0.999
Relative Throttle Position 5.9 %
Absolute Throttle Position B 15.7 %
Accelerator Pedal Position D 20.8 %
Accelerator Pedal Position E 10.2 %
Commanded Throttle Actuator 7.5 %
Control
I don’t know good values on the rest of these, but would be very interested in finding out about what the optimal Control Module Voltage should be… Keep reading and you will see why…
Side note cause I’m thinking of it… I did not find any correlation between weak/dead battery and PCM failure. But that does not mean it’s possible. I just have not found any information on it.
One should find out the reason the old PCM failed…
Most common reasons PCM fail: Voltage overloads or environmental factors.
Voltage overloads – short in a solenoid or actuator circuit. If the shorted solenoid or actuator isn’t found and repaired, the voltage overload it creates may damage the replacement PCM, too. Two different sources site shorted solenoids as a cause of PCM failure: Here’s one scenario-
Repeated emission system component failures may be caused by shorted output actuators (purge solenoid in EVAP system). Intermittent opens cause sudden voltage spikes that may cause repeated failures. Some output solenoids contain voltage suppression diodes that reduce voltage spikes when the solenoid is de-energized. A defective voltage suppression diode results in voltage spikes and possible repeated component failures. Excessive radio frequency interference may cause repeated component failures. A PCM may fail b/c of a shorted purge solenoid winding. IF the PCM is replaced without locating the cause of the failure in the purge solenoid, the PCM will fail again in a short time.
Most OBD II PCMs protect their circuits from shorted actuators and other electrical overloads. Installer should be inspecting harness connectors for corrosion or mechanical damage.
Do not touch the PCMs connector pins as a person’s body is capable of transmitting enough static electricity to degrade an interior component. Disconnect (-) neg battery cable when installing new PCM.
Install PCM in original mounting to eliminate vibration as a future cause of failure.
Environmental factors- Water- water gets inside PCM- short circuits, set up irreversible corrosion ruining electronic connections. Thermal Stress and vibration can form micro-cracks in circuit board (which are repairable). It is more often due with ruggedness of circuit design than vehicle operation factors.
If a remanufactured PCM is installed- it is always important to test engine functions such as fuel delivery and ignition to ensure off sensors and actuators are operating as designed. Some scan tools featuring bi-directional controls allow tech’s to activate ignition, fuel injection, fuel pump and other actuators for testing purposes.
I would add… after take the car thru 3 drive cycles (giving time for complete engine cool down between drive cycles and monitor PCM for pending (Maturing) fault codes or failures…
First off you get a lot a good data from your code reader... Would you mind telling me which one you have?? I don't get all that data from the current one I am using.
The $07e8 after the P0601 is just a number represented in the hexadecimal number system which is based on 16. Instead of the Decimal number system base of 10.
In Binary 07e8 is written as 0000 0111 1110 1000 or in the decimal number system it is the number 2024.
Not really going to help us at our level. So don’t worry about the $07E8.
Your Fuel status going into closed loop (is what is supposed to happen). Basically, the O2 sensors in the exhaust start producing a signal, the PCM switches into the closed-loop mode. (Open loop being the car is running on stored or preset data stored in the PCM so the car runs). Entering closed loop the car is now adjusting fuel delivery, spark advance, and idle speed to meet various operating conditions.
Another way to think of it would be... Open loop is like a carburetor choke... closed loop the car has warmed up and is using real time sensor data to run the car.
I don’t know what calculated load value means yet. Still learning all this stuff.
Obviously your car had been running temp as operating temp was 189F.
Short term and long term fuel trim:
Short term fuel trim (STFT) adjusts the injector pulse width to keep the system in closed loop. The system starts at a base figure and goes rich or lean from that point. (No idea what base figure is -- probably varies from engine to engine). If engine is right on- then corrections should be fairly small. STFT data is erased when ignition is turned off.
LTFT- is a shift in the base figure. If short term corrections are repeatedly pegged at their limits, then long term memory shifts. The starting point for STFT moves closer to the actual corrections that are needed. The system must be in closed loop to store changes in LTFT corrections. LTFT data are stored in memory even after ignition is turned off.
PCM uses STFT and LTFT factors to calculate total fuel correction to maintain closed loop. If system gets too lean or rich, fault data will be stored in PCM as a MATURING fault.
If the limit is exceeded on two consecutive trips the fault will Mature and then MIL comes on.
This goes back to knowing how the whole OBD II system works and when it activates the MIL. One fail is stored in PCM as a Maturing fault. Two fails on the second consecutive trip: the PCM takes the maturing fault and now says you’re mature... and turns on the dreaded MIL (Check engine light).
Now go back and refresh your memory on what a 'trip' and 'drive cycle' are...
It can get really complex, but most of the monitors in the OBD II system are two trip failures. So if you drive your vette in such a way that the car does not complete a drive cycle... (Say running a quick errand) the PCM will not test all its emissions tests.
So if you have a 1 trip fail stored in the PCM (as a Maturing fault), and on your next drive the car doesn't initiate that specific test, the PCM won’t be able to fail it a second time and turn on the MIL.
Here's my take... You never want to manually clear error codes from a PCM. The PCM will turn them off after 3 consecutive trips with no fails. Then erase them from PCM data after 40 warm up cycles... You should never let a car dealership clear the error codes from the PCM either...
You could have a 1 trip fault stored in the PCM for months if you only drive your vette in nice weather, non-rainy days, and store in winter, etc. And when you do finally drive it... If it does not complete a drive cycle then the fault does not mature- No MIL.
See the problem here... Erasing codes does not allow the PCM to check the system on its own and turn off the MIL after 3 good drive cycles...You could potentially have a 1 trip fail stored for several months... and say after you got the car fixed at a dealer and they clear the codes... how long before you drive it next time thru a complete drive cycle and the PCM finally takes that maturing code and makes it mature; and turn on the MIL--- or has two go thru two trips again before the MIL is turned on because the 1 maturing code was erased.
If your car is fixed for 2 trip fault MIL problem A, and problem B is only at one fail-- a maturing fault, and the codes are cleared, the stored 1 trip fail is gone… and will now take two more drive cycles to fail and turn the MIL back on for problem B.
Back to your code reads:
Intake Manifold Absolute Pressure- Unsure what a good reading on this is.
Ignition Timing Advance- ditto
Air Flow Rate from Mass Air Flow- ditto
Absolute Throttle Position – ditto
Commanded EVAP Purge – ditto- but since you have reading seems the EVAP purge test was completed.
Fuel Level Input- ditto
Number of warm-ups since 5
diagnostic trouble codes cleared
Distance since diagnostic trouble 51 miles
codes cleared
These are two good readings… If the MIL went out by itself like you said, then it appears you went thru 3 drive cycles and the PCM found no faults and turned out the MIL itself. To me this is being verified by the 5 warm up cycles count going on shown above… This counter will increase and eventually the PCM will erase any stored DTC’s
EVAP System Vapor Pressure - Unsure what a good reading on this is, but seems the EVAP purge test was completed
Catalyst Temperature Bank 1078 °F
1,Sensor 1
Catalyst Temperature Bank 1132 °F
2,Sensor 1
Control module voltage 13.521 V
Absolute Load Value 18.0 %
Commanded Equivalence Ratio 0.999
Relative Throttle Position 5.9 %
Absolute Throttle Position B 15.7 %
Accelerator Pedal Position D 20.8 %
Accelerator Pedal Position E 10.2 %
Commanded Throttle Actuator 7.5 %
Control
I don’t know good values on the rest of these, but would be very interested in finding out about what the optimal Control Module Voltage should be… Keep reading and you will see why…
Side note cause I’m thinking of it… I did not find any correlation between weak/dead battery and PCM failure. But that does not mean it’s possible. I just have not found any information on it.
One should find out the reason the old PCM failed…
Most common reasons PCM fail: Voltage overloads or environmental factors.
Voltage overloads – short in a solenoid or actuator circuit. If the shorted solenoid or actuator isn’t found and repaired, the voltage overload it creates may damage the replacement PCM, too. Two different sources site shorted solenoids as a cause of PCM failure: Here’s one scenario-
Repeated emission system component failures may be caused by shorted output actuators (purge solenoid in EVAP system). Intermittent opens cause sudden voltage spikes that may cause repeated failures. Some output solenoids contain voltage suppression diodes that reduce voltage spikes when the solenoid is de-energized. A defective voltage suppression diode results in voltage spikes and possible repeated component failures. Excessive radio frequency interference may cause repeated component failures. A PCM may fail b/c of a shorted purge solenoid winding. IF the PCM is replaced without locating the cause of the failure in the purge solenoid, the PCM will fail again in a short time.
Most OBD II PCMs protect their circuits from shorted actuators and other electrical overloads. Installer should be inspecting harness connectors for corrosion or mechanical damage.
Do not touch the PCMs connector pins as a person’s body is capable of transmitting enough static electricity to degrade an interior component. Disconnect (-) neg battery cable when installing new PCM.
Install PCM in original mounting to eliminate vibration as a future cause of failure.
Environmental factors- Water- water gets inside PCM- short circuits, set up irreversible corrosion ruining electronic connections. Thermal Stress and vibration can form micro-cracks in circuit board (which are repairable). It is more often due with ruggedness of circuit design than vehicle operation factors.
If a remanufactured PCM is installed- it is always important to test engine functions such as fuel delivery and ignition to ensure off sensors and actuators are operating as designed. Some scan tools featuring bi-directional controls allow tech’s to activate ignition, fuel injection, fuel pump and other actuators for testing purposes.
I would add… after take the car thru 3 drive cycles (giving time for complete engine cool down between drive cycles and monitor PCM for pending (Maturing) fault codes or failures…
11-17-2016, 12:39 PM
#17
General Motors (GM) OBD-II Driving Cycle
A complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes.
To perform an OBDII Driving cycle do the following:
Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.
Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.
Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.
Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.
A complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes.
To perform an OBDII Driving cycle do the following:
Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.
Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.
Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.
Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.
Last edited by DGresens; 11-17-2016 at 12:43 PM.
11-18-2016, 07:39 PM
#18
Instructor
Boy, that's a lot of info to digest from your last 2 posts.
To answer your question on my code reader, It's an Autel MD802 and I'm slowly learning how to use it. As I started digging deeper into the codes I noticed a zero 5-volt reference which would indicate a short somewhere. The APP values looked strange so I'll try to check that circuit this weekend. In the meantime the car cleared all the codes by itself and it's been running great.
To answer your question on my code reader, It's an Autel MD802 and I'm slowly learning how to use it. As I started digging deeper into the codes I noticed a zero 5-volt reference which would indicate a short somewhere. The APP values looked strange so I'll try to check that circuit this weekend. In the meantime the car cleared all the codes by itself and it's been running great.
