My C5 dash has gone nuts and I have every message there is!!!
07-14-2017, 10:38 PM
#41
Intermediate
Bill,
Many, many thanks for this info. I had the very problem today and I was able to quickly trace it to the connector for the drivers seat power. That connector rests right on the carpet, so if the carpet gets the least bit wet, the connector wicks it up and corrodes its pins. Luckily it was only one - the orange 12V power so I cut the orange wires as close as possible to the corroded connectors, stripped them back and crimped on some fully insulated spade connectors to bypass the corroded terminals - no need to buy the expensive replacement pins from the dealership. I zip tied the connectors to the underside of the seat to get them out of contact with the carpet too. All fixed. Thanks again.
Rob
Many, many thanks for this info. I had the very problem today and I was able to quickly trace it to the connector for the drivers seat power. That connector rests right on the carpet, so if the carpet gets the least bit wet, the connector wicks it up and corrodes its pins. Luckily it was only one - the orange 12V power so I cut the orange wires as close as possible to the corroded connectors, stripped them back and crimped on some fully insulated spade connectors to bypass the corroded terminals - no need to buy the expensive replacement pins from the dealership. I zip tied the connectors to the underside of the seat to get them out of contact with the carpet too. All fixed. Thanks again.
Rob
Last edited by tupeloC5; 07-14-2017 at 10:41 PM.
08-29-2017, 09:14 AM
#42
Drifting
Just wanted to say thanks to Bill for posting this thread. Great information within.
I will add my own experience in case someone else finds it helpful in their scenario.
A few months ago I took a ride out to my local road course for some open lapping in my 2000 FRC. It's about a 90m ride 1 way and I was loaded for bear with my trailer, race tires, tools, cooler, gas can, everything. Arrived at the track, unloaded, and went out for some warm up laps. After about 3 laps I turned up the wick and began pushing the car. 1 lap later I see the gauges freak out! Coolant 260F, Oil Pressure Max, Fuel Empty, Check Gages dummy light on, reduced engine power in DIC. It was impossible for the fuel to actually be empty while simultaneously overheating so I knew it was an electrical gremlin. The car still drove fine, full power, but I pitted to begin investigating.
I found this post on my phone and began trying the easy things - disconnect/reconnect negative battery terminal, reset BCM, wiggle the door harnesses. Nothing helped, the car would still freak out. I read some more posts regarding the seat harnesses getting wet, but figured this wasn't my problem because I have Honda S2000 seats installed, and the original C5 seat harnesses aren't even plugged in. However, just to be sure, I began investigating the carpet to make sure there was no moisture present. Everything felt nice and dry, no issues. On a whim, I decided to check the C5 seat harness to see how they looked. I noticed a glint of light coming from under the seat, pulled out the C5 driver's seat harness, and found a nice little present that had worked itself into the pigtail:
After laughing at the ridiculousness of the situation I grabbed a set of needlenose and removed Mr. Roosevelt from his new home; even got a tiny spark from him as he shorted the terminals one last time!
After another battery reset to clear the system, no more codes. I was out lapping again in minutes, and couldn't believe my luck. I plan on placing some protective electrical tape over BOTH seat harnesses since they are unused, and making sure no coins fall under the seats!
I will add my own experience in case someone else finds it helpful in their scenario.
A few months ago I took a ride out to my local road course for some open lapping in my 2000 FRC. It's about a 90m ride 1 way and I was loaded for bear with my trailer, race tires, tools, cooler, gas can, everything. Arrived at the track, unloaded, and went out for some warm up laps. After about 3 laps I turned up the wick and began pushing the car. 1 lap later I see the gauges freak out! Coolant 260F, Oil Pressure Max, Fuel Empty, Check Gages dummy light on, reduced engine power in DIC. It was impossible for the fuel to actually be empty while simultaneously overheating so I knew it was an electrical gremlin. The car still drove fine, full power, but I pitted to begin investigating.
I found this post on my phone and began trying the easy things - disconnect/reconnect negative battery terminal, reset BCM, wiggle the door harnesses. Nothing helped, the car would still freak out. I read some more posts regarding the seat harnesses getting wet, but figured this wasn't my problem because I have Honda S2000 seats installed, and the original C5 seat harnesses aren't even plugged in. However, just to be sure, I began investigating the carpet to make sure there was no moisture present. Everything felt nice and dry, no issues. On a whim, I decided to check the C5 seat harness to see how they looked. I noticed a glint of light coming from under the seat, pulled out the C5 driver's seat harness, and found a nice little present that had worked itself into the pigtail:
After laughing at the ridiculousness of the situation I grabbed a set of needlenose and removed Mr. Roosevelt from his new home; even got a tiny spark from him as he shorted the terminals one last time!
After another battery reset to clear the system, no more codes. I was out lapping again in minutes, and couldn't believe my luck. I plan on placing some protective electrical tape over BOTH seat harnesses since they are unused, and making sure no coins fall under the seats!
08-29-2017, 02:29 PM
#43
Tech Contributor
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St. Jude Donor '08
EXCELLENT STORY! Yeah, that Serial Data Buss doesn't like to be interrupted.. 
I saw a C5 Coupe on the side of the road once. As would be expected, I pulled over to see if he was OK.
NOTE. Car would crank but not run and the IPC had wacked out readings and messages.
SO,,,,,,,,,,,,,,,,,,,, I told him that the car was beyond repair and I would tow it off for him to save him money. LOL..
Then I grabbed the boot between the door and door frame, shook the hell out of it and told him to try to start it, BAM,,,,,, Cranked right up!
The look on his face was PRICELESS!
Bill
I saw a C5 Coupe on the side of the road once. As would be expected, I pulled over to see if he was OK.
NOTE. Car would crank but not run and the IPC had wacked out readings and messages.
SO,,,,,,,,,,,,,,,,,,,, I told him that the car was beyond repair and I would tow it off for him to save him money. LOL..
Then I grabbed the boot between the door and door frame, shook the hell out of it and told him to try to start it, BAM,,,,,, Cranked right up!
The look on his face was PRICELESS!
Bill
05-25-2018, 04:23 PM
#44
Advanced
Thanks bill
This post is being constructed to save my fingers and a little time. I have answered this question too many times to count so,, I'm making it something I can add to my File of saved post so that I can add it to any post asking for help when this issues happens as simply as copying the link or the information:
So,, your IPC goes crazy,, your door or doors don't work electrically and your getting NUMEROUS messages,,,, BUT,,,, you can still drive the car.
Some of you wont be able to start the car when the serial data buss goes crazy. That is what happens to my 02 ZO6 when the serial Data Buss get corrupted.
Heres what you need to do to troubleshoot the problem AND FIX IT.
Check the following:
1. Has water entered the passengers compartment? Is your Body Control Module (BCM) big silver box in the Passengers Foot Well behind the toe board wet or damp?
Feel the jute carpet underlayment and see if it is damp or wet. Move the passengers seat fully forward and run your hand up under the carpet and check the area under the seat. If you feel dampness, its very possible that the BCM got wet or damp! NOTE! The BCM DOES NOT LIKE WATER!!!!!!!! It MUST be dry to work properly!!
2. Do you have a Class 2 Serial Data Bus issue? If the data wires that connect each module short or get corrupt, It can cause the IPC to go crazy and display erroneous messages and alerts.
The most common cause of the data buss issues are moisture but, if your carpets and the BCM are DRY,, you could have an electrical issue.
There are THREE COMMON modules that frequently contribute to this issue. They are the: Left Door Control Module (LDCM), Right Door Control Module (RDCM) and the Seat Control Module (SCM)..
To figure out if one of the THREE modules are causing the issue, you can preform an easy procedure!
To the LEFT of the BCM are two thin connectors. They are the Class 2 Serial Data Bus STAR connectors. All the modules and the OBDII ALDL connector are connected together in both of these connectors:
The TOP of both of those thin connectors are a shorting bar that connects all the wires together in that connector.
If you remove the top "shorting bar", you open up (isolate) the modules that terminate in that connector. NOTE! Always examine the male and female pins inside the STAR Connectors when you open them up. There have been damaged connector from the factory.
If you remove the top of the STAR 2 Connector, (the one with FOUR wires in it) you isolate the serial data of the LDCM, RDCM and the SCM.
Once you have that connector disconnected, turn on the ignition switch and see if you clear the INSANITY! Then start the engine, CLEAR ALL THE DTCs and see if you have normal function of all the other modules. When you remove the top of that connector, You WILL have NO COMMS messaged for the three modules listed above. That is NORMAL!
If you regain normal functions,,, one or all three of the disconnected modules are causing the issue.
Start with the left and right door control modules. Another forum member found the cause of this issue so, its NOT my discovery.
For the longest time, it was believed that the wire in the clear sheaf that has exposed conductors caused this issue!!
WRONG!
Its a SPEAKER SHIELD WIRE and has NOTHING to do with the issue!
The real cause of the problem is poor connection/s in the door connectors. Mainly the power connector.
The rubber accordion tube between the doors is a conduit for the door WIRE HARNESS. Disconnect accordion tubes between the door and door frame. They easily pop in and out.
The door connectors live inside the hole in the DOOR FRAME "A" PILLAR. Fish the connectors out of the hole in the door frame. Yes,,, Its Short and will not pull out very far.
Disconnect the connectors and examine the male and female pins. The FEMALE pins in the connectors are easily damaged by heat and vibration and distort. When they distort, they make a POOR CONNECTION and any vibration can cause the power to that module to turn on and off rapidly. This causes the serial data buss data corruption. My ZO6 brand new purchased by ME from a dealer in 02 had bad pins and it was NEVER disturbed previously!! CRAZY!
Here is a good example of a power plug with a damaged FEMALE PIN:
The only way to properly test the female pins for proper mechanical contact with the male pin is to insert a proper size male pin into the female pin. Here is a picture of a pin that I use to test female pins:
When you insert the pin into the female pin, you should feel resistance inserting and removing it.
To fix the pin properly you should replace it BUT,,, if your careful, you can use a metal pick (I use a dental pick) and bend the metal tong back in place so that it makes positive contact with the male pin.
The seat control module connector under the DRIVERS SEAT sits very LOW and can easily be damaged when the seat moves, Check that connector for damaged wires.
If you have any MOISTURE (read water) under the drivers seat. it will SHORT OUT the SCM serial data wire!
Some stuff to know. There are other problems that can cause serial data buss issues. If all else fails and you can not figure out what module is causing serial data issues... disconnect BOTH CLASS 2 connector tops.
CONNECT the serial wire for the BCM & the PCM (PIN "M" and PIN "B") with a single wire. If the BCM and PCM are working properly the engine will start and run normally.
"U" series DTCs can indicate Module Communications or Power issues. Don't just ignore the U series DTCs
If a module fails to communicate, make SURE that it has proper POWER & GROUNDS
Most of the modules in your car have "TWO" 12 VDC power supplies. One that is called "HOT AT ALL TIMES" That BUS should read full battery voltage all the time! The voltage is used to keep module memory alive and to allow the module to function thru the BCM.
The other 12 VDC power is supplied to the modules when the ignition switch is ON or "HOT IN RUN & START"
The Ignition Switch gets it power from the HOT AT ALL TIMES bus and supplies switch power to the modules and fuel pump.
The IPC Digital Voltage reading in the DIC and the Instrument Cluster ANALOG VOLT METER get their power from the (HOT IN RUN & START) AFTER or thru the ignition switch.
The voltage readings on BOTH of those meters is NOT actual battery voltage. If the electrical contacts inside the IGNITION SWITCH are compromised, the voltage reading that you see will on both of those meters will be LESS than the actual HOT AT ALL TIMES bus voltage readings.
I have seen the output of the ignition switch read as low as 8 VDC because of bad electrical connections inside the ignition switch:
Here is a complete post that explains WHY and what to do to repair the ignition switch problem!
- C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
If you have water issues causing ANY of theses issues, look in the stickies for my leak check post.
Hope this helps someone get their C5 back on the road!
Bill Curlee
So,, your IPC goes crazy,, your door or doors don't work electrically and your getting NUMEROUS messages,,,, BUT,,,, you can still drive the car.
Some of you wont be able to start the car when the serial data buss goes crazy.
That is what happens to my 02 ZO6 when the serial Data Buss get corrupted.Heres what you need to do to troubleshoot the problem AND FIX IT.
Check the following:
1. Has water entered the passengers compartment? Is your Body Control Module (BCM) big silver box in the Passengers Foot Well behind the toe board wet or damp?
Feel the jute carpet underlayment and see if it is damp or wet. Move the passengers seat fully forward and run your hand up under the carpet and check the area under the seat. If you feel dampness, its very possible that the BCM got wet or damp! NOTE! The BCM DOES NOT LIKE WATER!!!!!!!! It MUST be dry to work properly!!
2. Do you have a Class 2 Serial Data Bus issue? If the data wires that connect each module short or get corrupt, It can cause the IPC to go crazy and display erroneous messages and alerts.
The most common cause of the data buss issues are moisture but, if your carpets and the BCM are DRY,, you could have an electrical issue.
There are THREE COMMON modules that frequently contribute to this issue. They are the: Left Door Control Module (LDCM), Right Door Control Module (RDCM) and the Seat Control Module (SCM)..
To figure out if one of the THREE modules are causing the issue, you can preform an easy procedure!
To the LEFT of the BCM are two thin connectors. They are the Class 2 Serial Data Bus STAR connectors. All the modules and the OBDII ALDL connector are connected together in both of these connectors:
The TOP of both of those thin connectors are a shorting bar that connects all the wires together in that connector.
If you remove the top "shorting bar", you open up (isolate) the modules that terminate in that connector. NOTE! Always examine the male and female pins inside the STAR Connectors when you open them up. There have been damaged connector from the factory.
If you remove the top of the STAR 2 Connector, (the one with FOUR wires in it) you isolate the serial data of the LDCM, RDCM and the SCM.
Once you have that connector disconnected, turn on the ignition switch and see if you clear the INSANITY! Then start the engine, CLEAR ALL THE DTCs and see if you have normal function of all the other modules. When you remove the top of that connector, You WILL have NO COMMS messaged for the three modules listed above. That is NORMAL!
If you regain normal functions,,, one or all three of the disconnected modules are causing the issue.
Start with the left and right door control modules. Another forum member found the cause of this issue so, its NOT my discovery.
For the longest time, it was believed that the wire in the clear sheaf that has exposed conductors caused this issue!!
WRONG!
Its a SPEAKER SHIELD WIRE and has NOTHING to do with the issue!
The real cause of the problem is poor connection/s in the door connectors. Mainly the power connector.
The rubber accordion tube between the doors is a conduit for the door WIRE HARNESS. Disconnect accordion tubes between the door and door frame. They easily pop in and out.
The door connectors live inside the hole in the DOOR FRAME "A" PILLAR. Fish the connectors out of the hole in the door frame. Yes,,, Its Short and will not pull out very far.
Disconnect the connectors and examine the male and female pins. The FEMALE pins in the connectors are easily damaged by heat and vibration and distort. When they distort, they make a POOR CONNECTION and any vibration can cause the power to that module to turn on and off rapidly. This causes the serial data buss data corruption. My ZO6 brand new purchased by ME from a dealer in 02 had bad pins and it was NEVER disturbed previously!! CRAZY!
Here is a good example of a power plug with a damaged FEMALE PIN:
The only way to properly test the female pins for proper mechanical contact with the male pin is to insert a proper size male pin into the female pin. Here is a picture of a pin that I use to test female pins:
When you insert the pin into the female pin, you should feel resistance inserting and removing it.
To fix the pin properly you should replace it BUT,,, if your careful, you can use a metal pick (I use a dental pick) and bend the metal tong back in place so that it makes positive contact with the male pin.
The seat control module connector under the DRIVERS SEAT sits very LOW and can easily be damaged when the seat moves, Check that connector for damaged wires.
If you have any MOISTURE (read water) under the drivers seat. it will SHORT OUT the SCM serial data wire!
Some stuff to know. There are other problems that can cause serial data buss issues. If all else fails and you can not figure out what module is causing serial data issues... disconnect BOTH CLASS 2 connector tops.
CONNECT the serial wire for the BCM & the PCM (PIN "M" and PIN "B") with a single wire. If the BCM and PCM are working properly the engine will start and run normally.
"U" series DTCs can indicate Module Communications or Power issues. Don't just ignore the U series DTCs
If a module fails to communicate, make SURE that it has proper POWER & GROUNDS
Most of the modules in your car have "TWO" 12 VDC power supplies. One that is called "HOT AT ALL TIMES" That BUS should read full battery voltage all the time! The voltage is used to keep module memory alive and to allow the module to function thru the BCM.
The other 12 VDC power is supplied to the modules when the ignition switch is ON or "HOT IN RUN & START"
The Ignition Switch gets it power from the HOT AT ALL TIMES bus and supplies switch power to the modules and fuel pump.
The IPC Digital Voltage reading in the DIC and the Instrument Cluster ANALOG VOLT METER get their power from the (HOT IN RUN & START) AFTER or thru the ignition switch.
The voltage readings on BOTH of those meters is NOT actual battery voltage. If the electrical contacts inside the IGNITION SWITCH are compromised, the voltage reading that you see will on both of those meters will be LESS than the actual HOT AT ALL TIMES bus voltage readings.
I have seen the output of the ignition switch read as low as 8 VDC because of bad electrical connections inside the ignition switch:
Here is a complete post that explains WHY and what to do to repair the ignition switch problem!
- C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
If you have water issues causing ANY of theses issues, look in the stickies for my leak check post.
Hope this helps someone get their C5 back on the road!
Bill Curlee
Thanks Bill. After living with the problem for a very long time I got it fixed. As mentioned no help from my local dealer. You came thru for me and my baby. Can't thank you enough. Tinbird02
05-27-2018, 04:05 PM
#46
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St. Jude Donor '08
Excellent!! What all did you do to resolve the issues???
Let the people know.
Let the people know.
05-30-2018, 10:43 AM
#47
Advanced
dry at this point. Opened three side connectors first and checked contacts. I made a tool for pushing into contacts using my wife metal cuticle pusher. need to sand in down a little but worked great. open both class 2 data ports. I found one pin askew ,so I moved it very carefully back in position. Check all pins and then sprayed electrical contact spay on the and reinstalled. Pulled door connectors out of door panels and used same tool to reposition females to accept males tightly. Sprayed all and reinstalled.
Took about two hours and compete. May baby is sound again.
Thanks to Bill and all. Forum came thru again.
Tinbird02
The following users liked this post:
nsogiba (05-30-2018)
09-01-2018, 09:05 PM
#48
Intermediate
Well, it finally happened to me. My 03 had intermittent issues with the driver door not unlocking via remote or door panel switch. Now, it refuses to unlock with either remote or panel switch. I haven't taken the panel off yet. Getting as much info as I can. When operating the door panel switch or the remote to unlock the doors, the relay can be heard switching inside the driver door. The lock does not move. If you unlock the door manually, the door switch and remotes with lock the doors just fine. I hear the same sound of a relay clicking but when unlocking, I don't get the noise of the linkage/cable moving the lock mechanism.
Any ideas on this one? No other errors or issues. Just no mechanical unlocking of the driver door, passenger door works fine. I am hoping it is something with a solenoid or whatever operates the mechanical connection that the LDCM relay is telling to function.
I am hoping to get the door panel off tomorrow and have a good look at it.
Thanks in advance!
Any ideas on this one? No other errors or issues. Just no mechanical unlocking of the driver door, passenger door works fine. I am hoping it is something with a solenoid or whatever operates the mechanical connection that the LDCM relay is telling to function.
I am hoping to get the door panel off tomorrow and have a good look at it.
Thanks in advance!
09-01-2018, 09:33 PM
#49
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St. Jude Donor '08
TRY THIS: Pop out the rubber accordion tube for that door. While you hold the buttons down for a door function, twist, wiggle the SIX PIN POWER CONNECTOR and see if you gain any functions. Do the same for the connectors inside the door once you get the panel off. If you still don't get anything, BUMP / WRAP door motor with a small rubber mallet and see if it starts working while holding down a button.
Next will be to see if you have full power and full current on all the door power fuses. Check all the fuses to chassis ground on each fuses test slots to ground.
BC
Next will be to see if you have full power and full current on all the door power fuses. Check all the fuses to chassis ground on each fuses test slots to ground.
BC
09-01-2018, 09:38 PM
#50
Intermediate
TRY THIS: Pop out the rubber accordion tube for that door. While you hold the buttons down for a door function, twist, wiggle the SIX PIN POWER CONNECTOR and see if you gain any functions. Do the same for the connectors inside the door once you get the panel off. If you still don't get anything, BUMP / WRAP door motor with a small rubber mallet and see if it starts working while holding down a button.
Next will be to see if you have full power and full current on all the door power fuses. Check all the fuses to chassis ground on each fuses test slots to ground.
BC
Next will be to see if you have full power and full current on all the door power fuses. Check all the fuses to chassis ground on each fuses test slots to ground.
BC
Thanks for the quick reply. Will post up results when I get out in the sweat box. Way too hot to be doing this, but, have to get it working. At least no drivability issues.......
09-01-2018, 09:57 PM
#51
Intermediate
Progress! Pulled the rubber accordion off of the pillar and got the wire connector out. Just moving it allowed the lock to work in open and close. Moved it again and lock worked but unlock did not. Moved around and back to full function. So this is the miserable troublemaker! Disconnected the connector and checked pins and sockets. All looks good. Plugged back in, all worked. Pushed wires back into pillar opening and unlock failed again. Pulled out and disconnected. Used a little contact cleaner in both male and female plugs, reconnected and tested. All working fine. Put wires back into pillar, retest, all good. Replaced boot, tested, still working. I'll try it again later. So the relay in the DCM is cycling, but, no function in the mechanism. Is there a power wire in the connector that is the supply to the unlock motor? That would at least make a little sense.
Thanks BC for the help!!!
Thanks BC for the help!!!
12-31-2021, 11:02 PM
#52
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DIC not working anymore
Heavy rain past couple days. Drivers carpet right by seat controls and SCM definitely damp and seat was going crazy so I pulled the fuse. Seat doesn’t move anymore now but it’s definitely causing my DIC problems I believe. DIC stopped working and every once in a while tachometer goes crazy for 1 second then back to normal. What’s the fix?
01-01-2022, 08:39 AM
#53
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Welcome to the Forum. The crazy seat caused by the heavy rain is an effect and not the cause…you will need to clean your cowl drain “udders” first and then concentrate on the SCM…you can see what happens after a few days letting the SCM dry out or use a hair dryer or heat gun…if still no luck I’d replace the SCM…water and electronics don’t mix !!…the serial data wire which ties all of the cars modules together is being back fed a power or ground from the wet SCM and once that happens the DIC starts throwing all warning messages, power windows may not work, water temp gauge maxes out and the fuel gauge goes to “E”…HAPPY NEW YEAR !!
Last edited by C5 Diag; 01-01-2022 at 08:52 AM.
06-28-2022, 06:11 PM
#54
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Thank you
The passenger window and lock stopped working after a. Ice cream stop on a road trip. I also had reduced power, no functioning shocks, etc on the display.
I looked up the symptoms, disconnected the passenger door connector in the rubber tube. I saw no evidence of corrosion but after reconnecting, Everything worked!
The info on the website saved untold grief and expense.
I looked up the symptoms, disconnected the passenger door connector in the rubber tube. I saw no evidence of corrosion but after reconnecting, Everything worked!
The info on the website saved untold grief and expense.
