Active handling defeated!
04-14-2016, 12:04 PM
#81
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Location: Charlotte, NC (formerly Endicott, NY)
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Thanks to Richie Rich I did this mod to my car this evening (disconnected Steering Wheel Sensor) and it solved a major problem. I was about ready to cancel my trip to Vegas this weekend for the Ultimate Street Car series. Thanks Again Rich.
My car is a 2009 Z06 and was going into reduced power mode at random times while shifting from 1st to 2nd or from 2nd to third. It was showing codes C0242 PCM indicated traction control malfunction, C0161 ABS/TCS Brake Switch Circuit Fault, U1017 Lost Communication with ECM/PCM, U1040 Lost Communication with EBCM/EBTCM. This problem started after the car was modified and working correctly.
While this fix saves me for now I am in the process of upgrading my 2009 Z06 to the launch control / PTM that comes on the newer Z06s and ZR1s. Bought all the computers but not installed yet. Therefore I need to have Active Handling working. My issues may stem from the fact that I have a highly modified 750HP car with a Harrop Hurricane 8 port ITB manifold. I am also running Rival S 315 and 345 which are smaller in diameter than stock. TPMS are installed and working fine. Hubs (wheels sensors) have been replaced, throttle sensor, brake sensor and clutch sensor have all been replaced none of that fixed it. I also have a Tilton clutch that enganges at the very top of the pedal throw. I have done the relearn for Steering sensor, brake and clutch sensors. To accommodate the Harrop I had to make a bunch of unusual modifications to the programming. For example the throttle tables have been reduced to 20% of their original values because I am feeding the engine with 8 55mm throttle blades.
So my question is what is causing the reduced power mode? I looked up the codes on identifix and they were saying that the ECM is seeing a code from the EBCM and putting it in reduced power mode. I am assuming that is the code C0161 Brake Sensor but I replaced it already. So why is the brake sensor creating a problem when I am shifting gears? I have monitored the ABS system voltage and the speed sensors which are about 2 or 3 MPH apart front to rear (this might be a problem?).
Oh one more weird thing, occasionally the throttle sticks at 2000 RPM so I was thinking TPS or maybe the throttle motor which is off of an LS1 to work with the Harrop Manifold. Shutting the car off, turning the ignition on, hitting the throttle clears this problem. Could a bad TPS not throw a code but put the car into reduced power mode? Same question on the throttle motor.
Help!
My car is a 2009 Z06 and was going into reduced power mode at random times while shifting from 1st to 2nd or from 2nd to third. It was showing codes C0242 PCM indicated traction control malfunction, C0161 ABS/TCS Brake Switch Circuit Fault, U1017 Lost Communication with ECM/PCM, U1040 Lost Communication with EBCM/EBTCM. This problem started after the car was modified and working correctly.
While this fix saves me for now I am in the process of upgrading my 2009 Z06 to the launch control / PTM that comes on the newer Z06s and ZR1s. Bought all the computers but not installed yet. Therefore I need to have Active Handling working. My issues may stem from the fact that I have a highly modified 750HP car with a Harrop Hurricane 8 port ITB manifold. I am also running Rival S 315 and 345 which are smaller in diameter than stock. TPMS are installed and working fine. Hubs (wheels sensors) have been replaced, throttle sensor, brake sensor and clutch sensor have all been replaced none of that fixed it. I also have a Tilton clutch that enganges at the very top of the pedal throw. I have done the relearn for Steering sensor, brake and clutch sensors. To accommodate the Harrop I had to make a bunch of unusual modifications to the programming. For example the throttle tables have been reduced to 20% of their original values because I am feeding the engine with 8 55mm throttle blades.
So my question is what is causing the reduced power mode? I looked up the codes on identifix and they were saying that the ECM is seeing a code from the EBCM and putting it in reduced power mode. I am assuming that is the code C0161 Brake Sensor but I replaced it already. So why is the brake sensor creating a problem when I am shifting gears? I have monitored the ABS system voltage and the speed sensors which are about 2 or 3 MPH apart front to rear (this might be a problem?).
Oh one more weird thing, occasionally the throttle sticks at 2000 RPM so I was thinking TPS or maybe the throttle motor which is off of an LS1 to work with the Harrop Manifold. Shutting the car off, turning the ignition on, hitting the throttle clears this problem. Could a bad TPS not throw a code but put the car into reduced power mode? Same question on the throttle motor.
Help!
DTC C0242: ECM Indicated TCS Malfunction
Circuit/System Description
The electronic brake control module (EBCM) and the engine control module (ECM) simultaneously control the traction control. The EBCM sends a high speed GMLAN serial data message to the ECM requesting torque reduction. When certain ECM DTCs are set, the ECM will not be able to perform the torque reduction for traction control. A serial data message is sent to the EBCM indicating that traction control is not allowed.
Conditions for Running the DTC
• The ignition is ON.
•Ignition voltage is greater than 8 volts.
Conditions for Setting the DTC
The ECM diagnoses a condition preventing the engine control portion of the traction control function and sends a serial data message to the EBCM indicating that torque reduction is not allowed. The ECM will typically set other DTCs and the EBCM will set DTC C0242.
Action Taken When the DTC Sets
• The EBCM disables the traction control system (TCS) for the duration of the ignition cycle.
• A DIC message and/or a warning message may be displayed.
• The antilock brake system (ABS) remains functional.
Conditions for Clearing the DTC
• The condition for the DTC is no longer present.
• The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
This DTC is for information only. As an aid to the technician, this DTC indicates that there are no problems in the ABS/TCS.
C0161 just tells you there is an issue with that sensor and the ABS, TC and AH functions are suspended until the problem is resolved. They do not affect the engine control. It just reduces the car to running with base brakes like all cars ran before 1985 or so.
DTC C0161 00: Antilock Brake System (ABS) Brake Switch Circuit
Circuit/System Description
The electronic brake control module (EBCM) detects inputs from the brake pressure sensor, vehicle speed, and a serial data message from the BCM that the brake pedal is applied. When the vehicle is stopping the EBCM monitors for the brake pedal is pressed, with the brake pressure increasing and the vehicle is slowing down, or when the vehicle is accelerating, the brake pedal is not pressed and brake pressure is not increasing.
Conditions for Running the DTC
• The vehicle speed is greater than 16 km/h (10 mph).
• The ignition voltage is greater than 9.5 volts.
Conditions for Setting the DTC
• The EBCM detects the vehicle speed greater than 21 km/h (13 mph), the brake pedal is Applied for 1 minute , and brake pressure is not increasing.
• The EBCM detects brake pedal is Released and the vehicle speed is decreasing with the brake pressure is increasing.
Action Taken When the DTC Sets
• The EBCM disables the antilock brake system (ABS), traction control system (TCS) and vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
• A DIC message and/or a warning indicator may be displayed.
Conditions for Clearing the DTC
• The condition for the DTC is no longer present.
• The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
The DTC C0161 00 can be set if the brake pedal is applied while accelerating.
This may be splitting hairs but as far as I can tell the EBCM doesn't put the car in reduced power mode at any time.
It can request a reduction in torque from the ECM if TC is turned on and it senses a wheel slip situation. But that is a quick reduction just to resolve the wheel slip. If the wheel speed sensors see a continual slippage of the rear wheels the EBCM asks for a torque reduction but if that doesn't work it applies the rear brakes. You can duplicate that situation by having smaller diameter tires on the rear than the front then try to coast the car downhill in neutral and it will come to a stop as the EBCM applies the brakes.
Another way to verify the EBCM isn't causing your issue is to remove the fuses that supply power to the EBCM. If it isn't powered up it can't do anything.
Bill
Last edited by Bill Dearborn; 04-14-2016 at 12:06 PM.
05-10-2016, 02:39 PM
#82
Okay, quick question on this.
If you hold down the traction control button and disable the traction control and active handling, does that prevent the active handling from kicking in?
If you hold down the traction control button and disable the traction control and active handling, does that prevent the active handling from kicking in?
05-10-2016, 03:29 PM
#84
05-10-2016, 04:46 PM
#87
05-11-2016, 03:43 PM
#88
Burning Brakes
You are good with connector unplugged, system defaults to off since it won't be able to tell which way you want to go vs which way you are actually going. I'm not sure if this holds true for z07's, carbons, or PTM equipped cars. I believe they may default the shock stiffness to full soft which would suck.
05-11-2016, 06:47 PM
#89
Yes it certainly will. I just had this happen to me when a TPMS briefly lost communication with the car. Luckily I was taking it easy for a lap to cool the brakes. I was going through a turn at about 75ish and the car snatched the wheel out of my hands and sent me straight(which was off the track) until the car slowed to 55 mph. Then it still went apeshit using active handling to try and straighten the car out going slow through other turns on my way back to the pits. Not a big deal this time but could have been if I were going much faster or in a different section of track.
How did you determine that the cause was a temporary loss of TPMS communication and not something else?
Thanks in advance for any clarification. I have had tpms issues in the past and want to avoid possible future issues by learning from others like yourself.
05-11-2016, 10:58 PM
#90
Burning Brakes
When you say the "car snatched the wheel out of my hands" , I assume that you meant it felt like it steered in a different direction due to the car applying individual brakes, not that it can control the steering wheel, right?
How did you determine that the cause was a temporary loss of TPMS communication and not something else?
Thanks in advance for any clarification. I have had tpms issues in the past and want to avoid possible future issues by learning from others like yourself.
How did you determine that the cause was a temporary loss of TPMS communication and not something else?
Thanks in advance for any clarification. I have had tpms issues in the past and want to avoid possible future issues by learning from others like yourself.
I looked down at the DIC and saw a "service TPMS soon" or something like that and the light in the cluster was illuminated. The yellow one that resembles a under inflated tire. Sorry but I don't recall what the DIC message actually said. All I remember is thinking "fu*king tire pressure sensor got me!! I knew my time was coming!" I think it's a low battery in one of the sensors. Before I could get back to the pits the signal came back and everything was back to normal. These sensors are from 2010.
05-11-2016, 11:02 PM
#91
Burning Brakes
In my experience a low pressure condition doesn't cause active handling to intervene. It just illuminates the light on the cluster and constantly dings at you until pressure comes up. I think it's 22 psi and under and the light comes on.
05-13-2016, 10:36 AM
#92
Melting Slicks
I have a failed lateral accelerometer that's under the passenger seat. It was causing false signals and the system would randomly activate a rear brake going down the highway to correct a condition that didn't exist. There were numerous times the car just randomly lunged toward the shoulder before it faulted out. After the 3rd or 4th time, I parked the car in a big lot and yanked the steering position sensor.
That was a couple years ago now. So, the car hasn't had a working stability system in years. I personally feel it isn't really needed, since I've had no issues at all even in heavy downpours and in freezing weather with 640rwhp and R Comp tires with no tread. I'll probably buy another sensor, someday, just to get everything working again.
That was a couple years ago now. So, the car hasn't had a working stability system in years. I personally feel it isn't really needed, since I've had no issues at all even in heavy downpours and in freezing weather with 640rwhp and R Comp tires with no tread. I'll probably buy another sensor, someday, just to get everything working again.
Last edited by Quickshift_C5; 05-13-2016 at 10:37 AM.
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HC Mechanic (01-28-2018)
05-14-2016, 10:21 PM
#93
Quick update: The problem came back. Turns out it was the throttle stop on my Harrop Hurricane manifold. At certain times the throttle motor would not be able to return to its expected location confusing the computer to think the throttle was stuck. I back off the stop about an 8th of a turn and problem solved.
C0242 is an information code that is sent to the EBCM by the ECM telling the ECM can't control torque properly. The EBCM responds by deactivating TC. Basically, it is a code that tells you TC isn't operating and the fault is in the ECM and not in the EBCM. Look at your ECM inputs and tune to find the problem.
DTC C0242: ECM Indicated TCS Malfunction
Circuit/System Description
The electronic brake control module (EBCM) and the engine control module (ECM) simultaneously control the traction control. The EBCM sends a high speed GMLAN serial data message to the ECM requesting torque reduction. When certain ECM DTCs are set, the ECM will not be able to perform the torque reduction for traction control. A serial data message is sent to the EBCM indicating that traction control is not allowed.
Conditions for Running the DTC
• The ignition is ON.
•Ignition voltage is greater than 8 volts.
Conditions for Setting the DTC
The ECM diagnoses a condition preventing the engine control portion of the traction control function and sends a serial data message to the EBCM indicating that torque reduction is not allowed. The ECM will typically set other DTCs and the EBCM will set DTC C0242.
Action Taken When the DTC Sets
• The EBCM disables the traction control system (TCS) for the duration of the ignition cycle.
• A DIC message and/or a warning message may be displayed.
• The antilock brake system (ABS) remains functional.
Conditions for Clearing the DTC
• The condition for the DTC is no longer present.
• The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
This DTC is for information only. As an aid to the technician, this DTC indicates that there are no problems in the ABS/TCS.
C0161 just tells you there is an issue with that sensor and the ABS, TC and AH functions are suspended until the problem is resolved. They do not affect the engine control. It just reduces the car to running with base brakes like all cars ran before 1985 or so.
DTC C0161 00: Antilock Brake System (ABS) Brake Switch Circuit
Circuit/System Description
The electronic brake control module (EBCM) detects inputs from the brake pressure sensor, vehicle speed, and a serial data message from the BCM that the brake pedal is applied. When the vehicle is stopping the EBCM monitors for the brake pedal is pressed, with the brake pressure increasing and the vehicle is slowing down, or when the vehicle is accelerating, the brake pedal is not pressed and brake pressure is not increasing.
Conditions for Running the DTC
• The vehicle speed is greater than 16 km/h (10 mph).
• The ignition voltage is greater than 9.5 volts.
Conditions for Setting the DTC
• The EBCM detects the vehicle speed greater than 21 km/h (13 mph), the brake pedal is Applied for 1 minute , and brake pressure is not increasing.
• The EBCM detects brake pedal is Released and the vehicle speed is decreasing with the brake pressure is increasing.
Action Taken When the DTC Sets
• The EBCM disables the antilock brake system (ABS), traction control system (TCS) and vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
• A DIC message and/or a warning indicator may be displayed.
Conditions for Clearing the DTC
• The condition for the DTC is no longer present.
• The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
The DTC C0161 00 can be set if the brake pedal is applied while accelerating.
This may be splitting hairs but as far as I can tell the EBCM doesn't put the car in reduced power mode at any time.
It can request a reduction in torque from the ECM if TC is turned on and it senses a wheel slip situation. But that is a quick reduction just to resolve the wheel slip. If the wheel speed sensors see a continual slippage of the rear wheels the EBCM asks for a torque reduction but if that doesn't work it applies the rear brakes. You can duplicate that situation by having smaller diameter tires on the rear than the front then try to coast the car downhill in neutral and it will come to a stop as the EBCM applies the brakes.
Another way to verify the EBCM isn't causing your issue is to remove the fuses that supply power to the EBCM. If it isn't powered up it can't do anything.
Bill
DTC C0242: ECM Indicated TCS Malfunction
Circuit/System Description
The electronic brake control module (EBCM) and the engine control module (ECM) simultaneously control the traction control. The EBCM sends a high speed GMLAN serial data message to the ECM requesting torque reduction. When certain ECM DTCs are set, the ECM will not be able to perform the torque reduction for traction control. A serial data message is sent to the EBCM indicating that traction control is not allowed.
Conditions for Running the DTC
• The ignition is ON.
•Ignition voltage is greater than 8 volts.
Conditions for Setting the DTC
The ECM diagnoses a condition preventing the engine control portion of the traction control function and sends a serial data message to the EBCM indicating that torque reduction is not allowed. The ECM will typically set other DTCs and the EBCM will set DTC C0242.
Action Taken When the DTC Sets
• The EBCM disables the traction control system (TCS) for the duration of the ignition cycle.
• A DIC message and/or a warning message may be displayed.
• The antilock brake system (ABS) remains functional.
Conditions for Clearing the DTC
• The condition for the DTC is no longer present.
• The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
This DTC is for information only. As an aid to the technician, this DTC indicates that there are no problems in the ABS/TCS.
C0161 just tells you there is an issue with that sensor and the ABS, TC and AH functions are suspended until the problem is resolved. They do not affect the engine control. It just reduces the car to running with base brakes like all cars ran before 1985 or so.
DTC C0161 00: Antilock Brake System (ABS) Brake Switch Circuit
Circuit/System Description
The electronic brake control module (EBCM) detects inputs from the brake pressure sensor, vehicle speed, and a serial data message from the BCM that the brake pedal is applied. When the vehicle is stopping the EBCM monitors for the brake pedal is pressed, with the brake pressure increasing and the vehicle is slowing down, or when the vehicle is accelerating, the brake pedal is not pressed and brake pressure is not increasing.
Conditions for Running the DTC
• The vehicle speed is greater than 16 km/h (10 mph).
• The ignition voltage is greater than 9.5 volts.
Conditions for Setting the DTC
• The EBCM detects the vehicle speed greater than 21 km/h (13 mph), the brake pedal is Applied for 1 minute , and brake pressure is not increasing.
• The EBCM detects brake pedal is Released and the vehicle speed is decreasing with the brake pressure is increasing.
Action Taken When the DTC Sets
• The EBCM disables the antilock brake system (ABS), traction control system (TCS) and vehicle stability enhancement system (VSES) for the duration of the ignition cycle.
• A DIC message and/or a warning indicator may be displayed.
Conditions for Clearing the DTC
• The condition for the DTC is no longer present.
• The EBCM clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
Diagnostic Aids
The DTC C0161 00 can be set if the brake pedal is applied while accelerating.
This may be splitting hairs but as far as I can tell the EBCM doesn't put the car in reduced power mode at any time.
It can request a reduction in torque from the ECM if TC is turned on and it senses a wheel slip situation. But that is a quick reduction just to resolve the wheel slip. If the wheel speed sensors see a continual slippage of the rear wheels the EBCM asks for a torque reduction but if that doesn't work it applies the rear brakes. You can duplicate that situation by having smaller diameter tires on the rear than the front then try to coast the car downhill in neutral and it will come to a stop as the EBCM applies the brakes.
Another way to verify the EBCM isn't causing your issue is to remove the fuses that supply power to the EBCM. If it isn't powered up it can't do anything.
Bill
05-15-2016, 02:42 PM
#94
Quick update: The problem came back. Turns out it was the throttle stop on my Harrop Hurricane manifold. At certain times the throttle motor would not be able to return to its expected location confusing the computer to think the throttle was stuck. I back off the stop about an 8th of a turn and problem solved.
05-24-2016, 11:12 PM
#97
Burning Brakes
If you unplug the steering wheel position sensor the car can't intervene via active handling. It simply doesn't know what to do. I don't know if it has any impact on the shocks or PTM. I might try it this weekend and see.
05-25-2016, 06:34 PM
#98
Race Director
When the MSRC goes into a failure mode I believe the mag shocks go to their softest ride.
Maybe wouldn't be a problem on the street, and maybe not for straight-line drag strip driving either.
I don't think it would be good at all on a roadcourse track.
.
05-29-2016, 06:40 PM
#99
I'm just wondering if I will get the same results as the autocross guys. I don't want to be going to the track and one of the brakes locks up because of the damn tpms. Anyone have any luck with that LG trackbox they sell?
