Crazy Z06 SVC/ACT HD problem
08-20-2012, 02:11 PM
#1
Racer
Thread Starter
Crazy Z06 SVC/ACT HD problem
I'm getting ready to start changing hard parts on my C5z06 but before I do I thought someone else may have had the same issue.
Long story short I'm been dealing this issue for 2-3 months and the codes wont pin point exactly what the problem is. Additionally the car must be driven on the track to cause it to happen. The situation has repeated itself anytime I go on the track but this weekends TT experiance best discribes what is happening.
On the out lap going into the final turn I turn off the nannies(it acts the same way with all off or comp mode). Once I take the green flag I have 1.2 to 2.0 minutes then the computer shuts the car off briefly(normally at a speed north of 100) it then refires, if I try to drive the car hard again it keeps trying to shut down AND sometimes the front brakes start to pulse. Even if I pit in and turn the car off and sit for a few minutes and head back out the car does the same thing.
The DIC says SVC/ACT HD and sometimes it will jump the car back to normal mode.
Anyone else ever have this happen?
Long story short I'm been dealing this issue for 2-3 months and the codes wont pin point exactly what the problem is. Additionally the car must be driven on the track to cause it to happen. The situation has repeated itself anytime I go on the track but this weekends TT experiance best discribes what is happening.
On the out lap going into the final turn I turn off the nannies(it acts the same way with all off or comp mode). Once I take the green flag I have 1.2 to 2.0 minutes then the computer shuts the car off briefly(normally at a speed north of 100) it then refires, if I try to drive the car hard again it keeps trying to shut down AND sometimes the front brakes start to pulse. Even if I pit in and turn the car off and sit for a few minutes and head back out the car does the same thing.
The DIC says SVC/ACT HD and sometimes it will jump the car back to normal mode.
Anyone else ever have this happen?
08-20-2012, 04:43 PM
#3
Racer
Thread Starter
I dont have the car with me, I might be able to get the codes pulled tomorrow.
The codes I got pulled off the DIC back in June when this happened was:
58 SDM
60 IPC
AO-LDCM
A6SCM
10 PCM
28 TCS
40 BCM
The codes I got pulled off the DIC back in June when this happened was:
58 SDM
60 IPC
AO-LDCM
A6SCM
10 PCM
28 TCS
40 BCM
08-20-2012, 05:44 PM
#4
Drifting
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08-21-2012, 07:07 AM
#6
Burning Brakes
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I think Bill did an excellent job providing an answer.
Any code in the ABS system will automatically turn off the affected portions of the system so you don't have to do anything to turn it off and you will not get stuck. C1282 shuts down the Active Handling and the Traction Control but not the ABS. Here is the description of how this part of the system operates and the actions taken by the car when the code occurs.
DTC C1282
Circuit Description
The vehicle stability enhancement system (VSES) is activated by the electronic brake control mdoule (EBCM) calculating the desired yaw rate and comparing it to the actual yaw rate input. The desired yaw rate is calculated from measured steering wheel position, vehicle speed, and lateral acceleration. The difference between the desired yaw rate and actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. If the yaw rate error becomes too large, the EBCM will attempt to correct the vehicle's yaw motion by applying differential braking to the left or right front wheel.
The amount of differential braking applied to the left or right front wheel is based on both the yaw rate error and side slip rate error. The side slip rate error is a function of the lateral acceleration minus the product of the yaw rate and vehicle speed. The yaw rate error and side slip rate error are combined to produce the total delta velocity error. When the delta velocity error becomes too large and the VSES system activates, the drivers steering inputs combined with the differential braking will attempt to bring the delta velocity error toward zero.
The VSES activations generally occur during aggressive driving, in the turns or bumpy roads without much use of the accelerator pedal. When braking during VSES activation, the brake pedal will feel different than the ABS pedal pulsation. The brake pedal pulsates at a higher frequency during VSES activation.
Conditions for Running the DTC
The EBCM performs 6 different tests to detect a DTC condition. The numbers below correspond to the numbers in Conditions for Setting the DTC.
1. The yaw rate sensor bias test runs with the ignition ON.
2. The yaw rate sensor acceleration test runs with the ignition ON.
3. The yaw rate sensor circuit test runs with the vehicle stopped or with the vehicle speed greater than 45 km/h (28 mph).
4. The yaw rate isolation test runs with the following conditions:
-The brake pedal is not pressed.
-The ABS is not active.
-The vehicle speed is greater than 5 km/h (3 mph).
5. The above yaw rate isolation test run with the VSES active.
6. The false activation test runs with the VSES active.
Conditions for Setting the DTC
The EBCM performs 6 different tests to detect a DTC condition. The numbers below correspond to the numbers in Conditions for Running the DTC.
1. The yaw rate bias is greater than 7 degrees/second.
2. The yaw rate input change is greater than 390 degrees/second/second.
3. The yaw rate input voltage is less than 0.15 volts or greater than 4.85 volts for 1 second.
4. The yaw rate error is greater than 10 degrees/second 30 times within a drive cycle.
5. The yaw rate error is greater than 10 degrees/second for 5 seconds. Under this condition, this DTC will set along with DTC C1281.
6. The yaw rate error is greater than 10 degrees/second with the vehicle speed less than 60 km/h (37 mph) and the acceleration pedal is pressed more than 25 percent of the pedal travel range for 1 second during the VSES activation. Under this condition, this DTC will set along with DTC C1281.
Action Taken When the DTC Sets
The EBCM disables the VSES for the duration of the ignition cycle.
The Traction Control and Active Handling indicator turns ON.
The DIC displays the Service Active Handling message.
The ABS remains functional.
Bill
DTC C1282
Circuit Description
The vehicle stability enhancement system (VSES) is activated by the electronic brake control mdoule (EBCM) calculating the desired yaw rate and comparing it to the actual yaw rate input. The desired yaw rate is calculated from measured steering wheel position, vehicle speed, and lateral acceleration. The difference between the desired yaw rate and actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. If the yaw rate error becomes too large, the EBCM will attempt to correct the vehicle's yaw motion by applying differential braking to the left or right front wheel.
The amount of differential braking applied to the left or right front wheel is based on both the yaw rate error and side slip rate error. The side slip rate error is a function of the lateral acceleration minus the product of the yaw rate and vehicle speed. The yaw rate error and side slip rate error are combined to produce the total delta velocity error. When the delta velocity error becomes too large and the VSES system activates, the drivers steering inputs combined with the differential braking will attempt to bring the delta velocity error toward zero.
The VSES activations generally occur during aggressive driving, in the turns or bumpy roads without much use of the accelerator pedal. When braking during VSES activation, the brake pedal will feel different than the ABS pedal pulsation. The brake pedal pulsates at a higher frequency during VSES activation.
Conditions for Running the DTC
The EBCM performs 6 different tests to detect a DTC condition. The numbers below correspond to the numbers in Conditions for Setting the DTC.
1. The yaw rate sensor bias test runs with the ignition ON.
2. The yaw rate sensor acceleration test runs with the ignition ON.
3. The yaw rate sensor circuit test runs with the vehicle stopped or with the vehicle speed greater than 45 km/h (28 mph).
4. The yaw rate isolation test runs with the following conditions:
-The brake pedal is not pressed.
-The ABS is not active.
-The vehicle speed is greater than 5 km/h (3 mph).
5. The above yaw rate isolation test run with the VSES active.
6. The false activation test runs with the VSES active.
Conditions for Setting the DTC
The EBCM performs 6 different tests to detect a DTC condition. The numbers below correspond to the numbers in Conditions for Running the DTC.
1. The yaw rate bias is greater than 7 degrees/second.
2. The yaw rate input change is greater than 390 degrees/second/second.
3. The yaw rate input voltage is less than 0.15 volts or greater than 4.85 volts for 1 second.
4. The yaw rate error is greater than 10 degrees/second 30 times within a drive cycle.
5. The yaw rate error is greater than 10 degrees/second for 5 seconds. Under this condition, this DTC will set along with DTC C1281.
6. The yaw rate error is greater than 10 degrees/second with the vehicle speed less than 60 km/h (37 mph) and the acceleration pedal is pressed more than 25 percent of the pedal travel range for 1 second during the VSES activation. Under this condition, this DTC will set along with DTC C1281.
Action Taken When the DTC Sets
The EBCM disables the VSES for the duration of the ignition cycle.
The Traction Control and Active Handling indicator turns ON.
The DIC displays the Service Active Handling message.
The ABS remains functional.
Bill
08-21-2012, 07:27 AM
#8
Burning Brakes
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Good question, perhaps a bad connection to the sensor?
I also have a Service Active Handling issue in my C6 that only shows up at the track after a few laps. Just purchased a code reader that can read ABS codes so I hope to be able to get a basic diagnosis when I head to Watkins Glen in September.
There are a few really smart tech types (like Bill) that might be able to provide some guidance.
I also have a Service Active Handling issue in my C6 that only shows up at the track after a few laps. Just purchased a code reader that can read ABS codes so I hope to be able to get a basic diagnosis when I head to Watkins Glen in September.
There are a few really smart tech types (like Bill) that might be able to provide some guidance.
08-21-2012, 07:42 AM
#9
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Bill
Last edited by Bill Dearborn; 08-21-2012 at 07:46 AM.
08-21-2012, 07:51 AM
#10
Racer
Thread Starter
I've been having the shop that has been working on the car try to fix and locate the problem..........they indicated that the code suggested that it may be the yaw sensor. The shop is well respected and they have tried four times to figure it out(have not charged me for their efforts). They are to the point where they feel they would be guessing.
Im out of town but I hope to have the codes pulled from the car today that would have been thrown this weekend.
Im out of town but I hope to have the codes pulled from the car today that would have been thrown this weekend.
08-21-2012, 10:44 AM
#11
Racer
Thread Starter
Local tech just said the only code is C1282 and it is in history. He also said the he thought the steering control sensor might be reading incorrectly.
08-21-2012, 12:37 PM
#12
Pro
If the entire car is shutting down, I would recommend looking at car's main electrical wiring to and from the battery. I had a somewhat similar experience where after having a bunch of work done on my car, the entire car would shut down in some right hand turns. It would die for less than a second, then refire and continue. After this happened a couple of times during that first session, the car went into limp mode. It was pretty easy to diagnose because even my auxilary accessories, like my data system, were being shut down. Turned out there was a nut that wasn't tightened on the terminal of one of the main power feeds. So I'd double check you have good connections at the battery, fuse and relay panels, etc.
I wouldn't think the active handling system could shut down the entire car. It may just be acting up due to the other problem.
I wouldn't think the active handling system could shut down the entire car. It may just be acting up due to the other problem.
Last edited by MySR71; 08-21-2012 at 12:39 PM.
08-21-2012, 07:14 PM
#13
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I've been having the shop that has been working on the car try to fix and locate the problem..........they indicated that the code suggested that it may be the yaw sensor. The shop is well respected and they have tried four times to figure it out(have not charged me for their efforts). They are to the point where they feel they would be guessing.
Im out of town but I hope to have the codes pulled from the car today that would have been thrown this weekend.
Im out of town but I hope to have the codes pulled from the car today that would have been thrown this weekend.
It wouldn't hurt to ask them some questions and find out what they did. Ask them whether they made any voltage measurements on the signal lines, etc. I know a lot of good mechanics that get limp kneed when it comes to electronics especially if they have to do a jury rig of a test set up to duplicate measurements made by a Tech 2. That is probably one of the reasons designed the measurement capability in the Tech 2. That way the mechanic just plugs something in and doesn't have to read a schematic and figure out if he shorts wire X to ground wire Y should have a certain voltage on it.
Bill
08-22-2012, 11:32 AM
#15
Race Director
Any chance it's something simple - other owners have had similar problems related to their stainless steel brake lines, and it's an easy fix if you can isolate it to that:
http://forums.corvetteforum.com/auto...-problems.html
Bob
http://forums.corvetteforum.com/auto...-problems.html
Bob
08-22-2012, 12:24 PM
#16
Race Director
If the entire car is shutting down, I would recommend looking at car's main electrical wiring to and from the battery. I had a somewhat similar experience where after having a bunch of work done on my car, the entire car would shut down in some right hand turns. It would die for less than a second, then refire and continue. After this happened a couple of times during that first session, the car went into limp mode. It was pretty easy to diagnose because even my auxilary accessories, like my data system, were being shut down. Turned out there was a nut that wasn't tightened on the terminal of one of the main power feeds. So I'd double check you have good connections at the battery, fuse and relay panels, etc.
I wouldn't think the active handling system could shut down the entire car. It may just be acting up due to the other problem.
I wouldn't think the active handling system could shut down the entire car. It may just be acting up due to the other problem.
How's your battery & connections?
08-22-2012, 12:43 PM
#17
Team Owner
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Joe the fact that the entire car is shutting off and re-firing is disturbing. IMO that has to be a main power distribution issue. I.e. loose/chafed wire or a bad ground or something. If it only happens when high g-loads are experienced that could mean something is moving to cause the issue and it only moves when high levels of force are applied.
I know you probably don't have the time, but I'd put it on stands in my garage and start checking all the connections/sensors/grounds and then start testing circuitry.
When these cars get obscure electrical gremlins they can be most annoying
I know you probably don't have the time, but I'd put it on stands in my garage and start checking all the connections/sensors/grounds and then start testing circuitry.
When these cars get obscure electrical gremlins they can be most annoying
08-22-2012, 04:06 PM
#18
Racer
Thread Starter
I had thought previously that the battery ground was lose so I put a new bolt in it and packed the battery(its in the trunk) with foam etc so it couldnt shift around but that wasnt it.
Today we replaced the steering sensor as it was not reading properly.
I have already checked many of the connections but I just asked the local shop to go through it again, as I agree that you wouldnt think the nannies would'nt shut it down.........particularly a C5.
As to the stainless brake lines causing it I dont know since they havent been an issue for the past two years.
Today we replaced the steering sensor as it was not reading properly.
I have already checked many of the connections but I just asked the local shop to go through it again, as I agree that you wouldnt think the nannies would'nt shut it down.........particularly a C5.
As to the stainless brake lines causing it I dont know since they havent been an issue for the past two years.
08-22-2012, 05:42 PM
#19
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Stainless brake lines can make it throw AH/TCS codes if they're not grounding correctly. They build up a static charge and throw off the wheel speed sensor. The car thinks one of the sensors has gone bad and shuts down the system. All that does is turn off ABS/AH/TCS... it doesn't cause any power delivery issues. The car never misses a beat, it just flashes the message on the DIC. I only ever had this issue with an old set of Goodrige SS lines that were un-wrapped (no plastic sheathing) and used banjo bolts. After reading on the forum I swapped to newer Goodrige lines that used AN fittings, the theory being the AN adapter made for a better ground... no idea if it was true, but never had the codes from the lines again. That said, I've run Stoptech lines with banjo bolts w/o issues for years (still have them on my rear OEM calipers).
As far as I know non of the nannies will actually turn the car off. Kill power/limp mode... ok sure... but the car actually cutting off means something is happening with the alternator/battery output to the main distribution block under the hood or somewhere around there.
As far as I know non of the nannies will actually turn the car off. Kill power/limp mode... ok sure... but the car actually cutting off means something is happening with the alternator/battery output to the main distribution block under the hood or somewhere around there.
08-23-2012, 04:27 PM
#20
Racer
Thread Starter
Thanks for all the recommendaiton and advice here. As I mentioned earlier the steering sensor was'nt reading correctly so it remains to be seen if that is the SVC/ACT HD issue.
However this morning we found that there was about a 2" section of the positive battery line(battery is in the trunk) that was burnt and appeared as is it was touching the exhaust sometimes. The issue of the car shutting down started after I had the stock exhausted change to competition exhaust. I gotta believe this is the shutting down problem.
I hope to know for sure by Tuesday.
However this morning we found that there was about a 2" section of the positive battery line(battery is in the trunk) that was burnt and appeared as is it was touching the exhaust sometimes. The issue of the car shutting down started after I had the stock exhausted change to competition exhaust. I gotta believe this is the shutting down problem.
I hope to know for sure by Tuesday.