Column Lock and Stability Management
05-12-2014, 10:14 AM
#1
Melting Slicks
Thread Starter
Column Lock and Stability Management
Ok, guys...I'm at the end of my rope here and out of options on both of these systems I'm having issues with. I've read through threads and google searches until my head hurts. Been dealing with both of these problems for a long time now. If someone, anyone, has answers or serious suggestions to try...I'd be grateful. I realize there are virtual piles of threads for these, but I'm desperate. 
Column Lock
I had the "GM Fix" for the column lock done for my car back in 2009 when I bought it. They installed the K-Harness and non-locking plate. When I had my supercharger installed, it happened again when the shop had it. They maxed out the speed for fuel cut and I have been driving it the past 2 years since while trying to fix it. I have never removed the "K Harness" myself and can't find it, so I assume the shop that installed the blower removed it. Here is what I've tried:
1. Column Lock Bypass from Corvettes of Houston.
2. Used power adapter with car off to unlock column and then turned car on
3. Removed fuse #25 for 10+ minutes
4. Removed bypass and plugged back in like OEM
5. Searched for "K-Harness" to make sure it wasn't plugged in still. Can't find it.
6. Every combination of the above I could think of
Stability Control System Fault
For this problem, the code points directly at the yaw sensor. I've replaced the yaw sensor with no change. It only faults when you're really hard on the throttle. Sometimes, very seldom, it'll fault at random. When it faults, it's very dangerous as the system tries to lock up a brake before realizing it's way off and faults. I haven't done a whole lot since it points at the yaw sensor. I'd like to know what else would cause this and what could give a false yaw sensor error while being something else. Wheelspeed sensor out of whack? I've brought it to a couple GM dealers who ran a scanner across it and it shows no errors or points to a problem.
Any thoughts, guys?
Column Lock
I had the "GM Fix" for the column lock done for my car back in 2009 when I bought it. They installed the K-Harness and non-locking plate. When I had my supercharger installed, it happened again when the shop had it. They maxed out the speed for fuel cut and I have been driving it the past 2 years since while trying to fix it. I have never removed the "K Harness" myself and can't find it, so I assume the shop that installed the blower removed it. Here is what I've tried:
1. Column Lock Bypass from Corvettes of Houston.
2. Used power adapter with car off to unlock column and then turned car on
3. Removed fuse #25 for 10+ minutes
4. Removed bypass and plugged back in like OEM
5. Searched for "K-Harness" to make sure it wasn't plugged in still. Can't find it.
6. Every combination of the above I could think of
Stability Control System Fault
For this problem, the code points directly at the yaw sensor. I've replaced the yaw sensor with no change. It only faults when you're really hard on the throttle. Sometimes, very seldom, it'll fault at random. When it faults, it's very dangerous as the system tries to lock up a brake before realizing it's way off and faults. I haven't done a whole lot since it points at the yaw sensor. I'd like to know what else would cause this and what could give a false yaw sensor error while being something else. Wheelspeed sensor out of whack? I've brought it to a couple GM dealers who ran a scanner across it and it shows no errors or points to a problem.
Any thoughts, guys?
05-12-2014, 11:04 AM
#2
Melting Slicks
Thread Starter
I'll try the LMC5 module, it sounds promising. Thanks! 
As I mentioned in my first post, the DIC code points specifically at the Yaw Sensor. I've replaced that with a used one that had no effect. It could be that the used one I bought from a vendor is also bad, but highly unlikely.
As I mentioned in my first post, the DIC code points specifically at the Yaw Sensor. I've replaced that with a used one that had no effect. It could be that the used one I bought from a vendor is also bad, but highly unlikely.
05-12-2014, 11:22 AM
#3
Melting Slicks
Thread Starter
Another thought on the Stability Management problem.
What tire sizes are you running front and rear???
If you are not set up with the overall diameter of the rear tires being between 1/2" and 1 1/2" larger than the overall diameter of the front tires you will experience AH/TC symptoms without any codes being set...
What tire sizes are you running front and rear???
If you are not set up with the overall diameter of the rear tires being between 1/2" and 1 1/2" larger than the overall diameter of the front tires you will experience AH/TC symptoms without any codes being set...
05-12-2014, 11:33 AM
#5
Le Mans Master
I highly recommend the LMC5. NO ONE can help you better on CL issues than 8VETTE7.
He is also correct about the tire sizes.
You're saying you replaced the yaw sensor and it throws the same code again. What is the code?
I have read one guy had TPMS issues causing a similar scary issue like you have. I have the link at home. If I remember it did not throw a code though. We don't want to overlook anything.
It would not surprise me since it is random and just throwing one code that a scan might not show the root cause. If it is not the yaw sensor it must be one of the wheel sensor inputs or some kind of random EBCM or BCM issue. I don't think anything else inputs, not at home with the FSM.
The only other thing I could think of is under hard acceleration you get some tire slippage that activates the system but that alone should not throw a code.
Have you tried turning off TC and see if the issue can be duplicated? That would be useful info. I would drive without TC for a while and see if it does or does not happen again.
I sure hope it is not a wire somewhere in the circuit that is the issue. Can't think of anything else at this time.
He is also correct about the tire sizes.
You're saying you replaced the yaw sensor and it throws the same code again. What is the code?
I have read one guy had TPMS issues causing a similar scary issue like you have. I have the link at home. If I remember it did not throw a code though. We don't want to overlook anything.
It would not surprise me since it is random and just throwing one code that a scan might not show the root cause. If it is not the yaw sensor it must be one of the wheel sensor inputs or some kind of random EBCM or BCM issue. I don't think anything else inputs, not at home with the FSM.
The only other thing I could think of is under hard acceleration you get some tire slippage that activates the system but that alone should not throw a code.
Have you tried turning off TC and see if the issue can be duplicated? That would be useful info. I would drive without TC for a while and see if it does or does not happen again.
I sure hope it is not a wire somewhere in the circuit that is the issue. Can't think of anything else at this time.
Last edited by dadaroo; 05-12-2014 at 11:36 AM.
05-12-2014, 11:45 AM
#6
Melting Slicks
Thread Starter
There's only one code that talks about the Yaw Sensor folks, let's move forward from here. This is the only code that has even been indicated related to the system failure, past or present.
DTC C1282 Yaw Rate Sensor Bias Circuit Malfunction
It doesn't fault randomly, it will fault every time I'm very hard on the throttle. My tires don't spin at the speeds it usually faults at, but it has faulted a few times at lower speeds when they may have slipped. I can "disable" the system completely by holding the button for 8 seconds or so...but the fault still occurs.
Here is a video of my car faulting at the dragstrip.
Definitely appreciate the questions/suggestions so far, keep 'em coming!
DTC C1282 Yaw Rate Sensor Bias Circuit Malfunction
It doesn't fault randomly, it will fault every time I'm very hard on the throttle. My tires don't spin at the speeds it usually faults at, but it has faulted a few times at lower speeds when they may have slipped. I can "disable" the system completely by holding the button for 8 seconds or so...but the fault still occurs.
Here is a video of my car faulting at the dragstrip.
Definitely appreciate the questions/suggestions so far, keep 'em coming!
Last edited by Quickshift_C5; 05-12-2014 at 11:58 AM.
05-12-2014, 08:10 PM
#7
Le Mans Master
"There's only one code that talks about the Yaw Sensor folks, let's move forward from here. This is the only code that has even been indicated related to the system failure, past or present."
Really? I guess your FSM is different than mine. Who needs to move on?
Really? I guess your FSM is different than mine. Who needs to move on?
05-12-2014, 09:30 PM
#8
Melting Slicks
Thread Starter
If the code I mentioned that says "Yaw Rate Sensor" could actually be something else, I'm all ears. That's why I started the thread.
05-13-2014, 07:24 AM
#9
Le Mans Master
I teach and perform root cause failure analysis in the nuclear industry. I can't afford to not get as much information as possible. Most times the issues keep a plant from starting up or they may need to shut down if the issue cannot be explained and fixed. At upwards of 1 million dollars a day I have to put everything on the table and then prove what should be removed.
I needed to KNOW exactly what code you got, not assume.
I then went into the manual and started to search by READING what inputs affected other related AH problems and codes that had Yaw input.
In summary I still need to do more research.
Did you put in a new or used Yaw sensor? (Trust me I can tell you a story about trying to fix a locked up nuclear rod control system Christmas morning)
Just to make sure I understand (it is important): With the TC OFF you can still get the random braking, correct?
Does the following ever happen?
The Traction Control and Active Handling indicator turns ON.
The DIC displays the Service Active Handling message.
If you have not looked at the FSM here is a summary of your code:
DTC C1282
Circuit Description
The vehicle stability enhancement system (VSES) is activated by the electronic brake control module (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.
The yaw rate sensor bias test runs with the ignition ON.
The yaw rate sensor acceleration test runs with the ignition ON.
The yaw rate sensor circuit test runs with the vehicle stopped or with the vehicle speed greater than 45 km/h (28 mph).
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).
The above yaw rate isolation test run with the VSES active.
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.
The yaw rate bias is greater than 7 degrees/second.
The yaw rate input change is greater than 390 degrees/second/second.
The yaw rate input voltage is less than 0.15 volts or greater than 4.85 volts for 1 second.
The yaw rate error is greater than 10 degrees/second 30 times within a drive cycle.
The yaw rate error is greater than 10 degrees/second for 5 seconds. Under this condition, this DTC will set along with DTC C1281.
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.
Conditions for Clearing the DTC
The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
The scan tool may display 2 additional characters after the DTC. Take note of the 2 character code and any other DTCs that are set. The 2 character code is an engineering aid used in order to determine the specific criteria which caused the DTC to set.
During diagnosis, park the vehicle on a level surface.
Check the vehicle for proper alignment. The car should not pull in either direction while driving straight on a level surface.
Find out from the driver under what conditions the DTC was set (when the DIC displayed the Service Active Handling message). This information will help to duplicate the failure.
The Snapshot function on the scan tool can help find an intermittent DTC.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Tests for the proper operation of the circuit in the low voltage range.
Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
Tests for a short to voltage in the 5-volt reference circuit.
Tests the bias voltage of the yaw rate sensor.
I needed to KNOW exactly what code you got, not assume.
I then went into the manual and started to search by READING what inputs affected other related AH problems and codes that had Yaw input.
In summary I still need to do more research.
Did you put in a new or used Yaw sensor? (Trust me I can tell you a story about trying to fix a locked up nuclear rod control system Christmas morning)
Just to make sure I understand (it is important): With the TC OFF you can still get the random braking, correct?
Does the following ever happen?
The Traction Control and Active Handling indicator turns ON.
The DIC displays the Service Active Handling message.
If you have not looked at the FSM here is a summary of your code:
DTC C1282
Circuit Description
The vehicle stability enhancement system (VSES) is activated by the electronic brake control module (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.
The yaw rate sensor bias test runs with the ignition ON.
The yaw rate sensor acceleration test runs with the ignition ON.
The yaw rate sensor circuit test runs with the vehicle stopped or with the vehicle speed greater than 45 km/h (28 mph).
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).
The above yaw rate isolation test run with the VSES active.
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.
The yaw rate bias is greater than 7 degrees/second.
The yaw rate input change is greater than 390 degrees/second/second.
The yaw rate input voltage is less than 0.15 volts or greater than 4.85 volts for 1 second.
The yaw rate error is greater than 10 degrees/second 30 times within a drive cycle.
The yaw rate error is greater than 10 degrees/second for 5 seconds. Under this condition, this DTC will set along with DTC C1281.
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.
Conditions for Clearing the DTC
The condition for the DTC is no longer present and the DTC is cleared with a scan tool.
The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
The scan tool may display 2 additional characters after the DTC. Take note of the 2 character code and any other DTCs that are set. The 2 character code is an engineering aid used in order to determine the specific criteria which caused the DTC to set.
During diagnosis, park the vehicle on a level surface.
Check the vehicle for proper alignment. The car should not pull in either direction while driving straight on a level surface.
Find out from the driver under what conditions the DTC was set (when the DIC displayed the Service Active Handling message). This information will help to duplicate the failure.
The Snapshot function on the scan tool can help find an intermittent DTC.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Tests for the proper operation of the circuit in the low voltage range.
Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
Tests for a short to voltage in the 5-volt reference circuit.
Tests the bias voltage of the yaw rate sensor.
Last edited by dadaroo; 05-13-2014 at 07:26 AM.
05-13-2014, 11:50 AM
#10
Melting Slicks
Thread Starter
Did you put in a new or used Yaw sensor?
Just to make sure I understand (it is important): With the TC OFF you can still get the random braking, correct?
Does the following ever happen?
The DIC displays the Service Active Handling message YES
Tests for the proper operation of the circuit in the low voltage range.
Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
Tests for a short to voltage in the 5-volt reference circuit.
Tests the bias voltage of the yaw rate sensor.
Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
Tests for a short to voltage in the 5-volt reference circuit.
Tests the bias voltage of the yaw rate sensor.
I'm not sure how to perform these tests.
05-14-2014, 08:38 AM
#11
Le Mans Master
Thanks for the feedback.
You say you "disable" the system by holding the TC button down for 8 seconds. Sounds like you are not turning TC/AH OFF but just turning TC OFF and leaving AH ON and thereby going into Competitive Mode. Your DIC should display which is happening.
If this is true, I would be interested if by just pressing the TC button briefly and turning TC/AH OFF if this eliminates the random braking.
I don't think it is a problem with the replacement Yaw sensor.
It appears when it throws the C1282 code it does not turn ON the TC/AH indicator light. It should.
If with the TC/AH turned OFF you still get random braking. It should not.
It seems like the EBCM is making some independent decisions. The yaw sensor code being thrown seems like it may be a red herring. Your overall system appears to be not working as designed.
I found your Thread from March of this year. Do you still want to disable the entire system? ABS just slows your stopping distance if you are a good driver which you apparently are.
I am surprised no one has talked about just unplugging/depowering the EBCM. It should not affect anything else I can think off. I will look at the FSM and post a Thread asking the Forum this specific question. Seems like just pulling EBCM fuses 52 and 5 would disable it. Would light up some IPC bulbs which could always be removed or some black tape to mask.
BTW, I like your car and I also race too. All my cars have no ABS type systems except the C5 which I have not raced yet but every time I am out driving I turn TC/AH OFF. Wish I could just turn ABS OFF. I'm just an old school guy.
In summary, do you really want to figure out this issue or just eliminate the system. I will work with you either way.
You say you "disable" the system by holding the TC button down for 8 seconds. Sounds like you are not turning TC/AH OFF but just turning TC OFF and leaving AH ON and thereby going into Competitive Mode. Your DIC should display which is happening.
If this is true, I would be interested if by just pressing the TC button briefly and turning TC/AH OFF if this eliminates the random braking.
I don't think it is a problem with the replacement Yaw sensor.
It appears when it throws the C1282 code it does not turn ON the TC/AH indicator light. It should.
If with the TC/AH turned OFF you still get random braking. It should not.
It seems like the EBCM is making some independent decisions. The yaw sensor code being thrown seems like it may be a red herring. Your overall system appears to be not working as designed.
I found your Thread from March of this year. Do you still want to disable the entire system? ABS just slows your stopping distance if you are a good driver which you apparently are.
I am surprised no one has talked about just unplugging/depowering the EBCM. It should not affect anything else I can think off. I will look at the FSM and post a Thread asking the Forum this specific question. Seems like just pulling EBCM fuses 52 and 5 would disable it. Would light up some IPC bulbs which could always be removed or some black tape to mask.
BTW, I like your car and I also race too. All my cars have no ABS type systems except the C5 which I have not raced yet but every time I am out driving I turn TC/AH OFF. Wish I could just turn ABS OFF. I'm just an old school guy.
In summary, do you really want to figure out this issue or just eliminate the system. I will work with you either way.
05-14-2014, 10:26 AM
#12
Melting Slicks
Thread Starter
Yeah, I'm definitely giving some confusing feedback. I haven't messed with the TC system since last year and am just getting the button operation mixed up. Whether it's in Comp Mode (8sec) or Off (push once), it faults. I think when the system faults, the light does turn on. I will verify this when I can.
I would prefer to fix the system over bypassing it completely. There is a 1/2 Mile event coming up in late June, so I will need to bypass it for that if it hasn't been repaired. From what I've read, I should be able to just pull the steering angle sensor connector at the base of the column. When the car starts and does its checks, it should fault immediately instead of putting me in a possible dangerous position at an event. I will test this next time I drive the car.
Thanks again for the help.
I would prefer to fix the system over bypassing it completely. There is a 1/2 Mile event coming up in late June, so I will need to bypass it for that if it hasn't been repaired. From what I've read, I should be able to just pull the steering angle sensor connector at the base of the column. When the car starts and does its checks, it should fault immediately instead of putting me in a possible dangerous position at an event. I will test this next time I drive the car.
Thanks again for the help.
05-14-2014, 10:37 AM
#13
Race Director
Member Since: Apr 2007
Location: South Western Ontario
Posts: 11,061
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I recall reading something about a brace for the yaw sensor that keeps it from bouncing and producing issues under hard acceleration.
Pulling fuses would disable it. With no power it can't operate the brakes itself.
Pulling fuses would disable it. With no power it can't operate the brakes itself.
05-14-2014, 11:40 AM
#15
Le Mans Master
Great, thanks for you two guys inputting. I prefer to solve problems as a FORUM TEAM. I knew about the brace issue but pretty much discounted it as a concern since I though he was disabling TC/AH and still had the issue. Based on his last post that has changed. Please keep any other ideas flowing.
I figured he would want the system fixed since he does road racing also.
I think looking into the brace issue is the next logical step.
I figured he would want the system fixed since he does road racing also.
I think looking into the brace issue is the next logical step.
05-14-2014, 12:30 PM
#16
Melting Slicks
Thread Starter
One of the threads that was linked talked about the steering position sensor and that if the car didn't track straight, the issue may occur. On my car, it has NEVER perfectly tracked straight. It has always had a slight pull to the right. With all the tire changes, alignment changes, etc, it still pulls. I assumed it was a wheel issue and have been ignoring it. This has happened from day one, and years before I started having the problem. But...could it be related somehow?
05-14-2014, 05:03 PM
#17
Le Mans Master
YES, alignment can cause the issue you are having. Actual car movement versus where the wheel is pointed can do it. Just make sure that it actually tracks to the right even if you are on the middle of the road "crown". Roads are normally designed to be high in the center and slope down on each side.
05-14-2014, 05:57 PM
#18
Melting Slicks
Thread Starter
YES, alignment can cause the issue you are having. Actual car movement versus where the wheel is pointed can do it. Just make sure that it actually tracks to the right even if you are on the middle of the road "crown". Roads are normally designed to be high in the center and slope down on each side.
I'm going to take apart the dash tonight and inspect the yaw sensor, yaw sensor mounting bracket, and wiring.
05-14-2014, 10:37 PM
#19
Melting Slicks
Thread Starter
Took a good look at the Yaw Sensor and everything, physically, appears to be fine. It's secure, aligned, has no movement, bracket looks fine, and the plug/wiring look good. I have not checked it for proper operation with a meter since I don't have a FSM and not sure how to properly test it.
Here is the Yaw Sensor.
Here is the Yaw Sensor.