Keep getting a ‘stabiliTrak service and service traction’ error message. The ‘brake pedal sensor switch’ has been replaced and now the message appears only when the engine is idling for more than a few minutes (disappears once I start driving). What could cause the message to keep appearing?
RESPONSE
My first guess would be a faulty sensor or sensor connection. However some hands on testing would be needed to locate the issue.
This vehicle is equipped with a BOSCH ABS/EBD/TCS/VSES brake system. The electronic brake control module (EBCM) and the brake pressure modulator valve (BPMV) is serviced separately. The BPMV uses a 4 circuit configuration to control hydraulic pressure to each wheel independently.
The following vehicle performance enhancement systems are provided.
| • | Electronic Brake Distribution (EBD) |
| • | Power Brake Booster Solenoid Vacuum Supply |
| • | Traction Control System (TCS) |
| • | Vehicle Stability Enhancement System (VSES) |
StabiliTrak® Indicator Light
If equipped, this warning light should come on briefly when the engine is started.
If the warning light does not come on then, have it fixed so it will be ready to warn you if there is a problem. If it stays on, or comes on when you are driving, there may be a problem with your StabiliTrak® system and your vehicle may need service. When this warning light is on, the system is off and will not limit wheel spin. Adjust your driving accordingly.
This light will also flash when the StabiliTrak® system is active.
If the StabiliTrak® system warning light comes on and stays on for an extended period of time when the system is turned on, your vehicle needs service.
Service StabiliTrak Message
Service Traction Control Message
StabiliTrak Off Message
| • | The transfer case is shifted into 4 LO. The EBCM sends a serial data message to the IPC requesting illumination. |
| • | The driver manually disables the VSES and engine torque reduction by pressing the traction control switch. The EBCM sends a serial data message to the IPC requesting illumination. |
| • | The estimated temperature of any solenoid coil exceeds an acceptable limit. The EBCM sends a serial data message to the IPC requesting this display. |
| • | The EBCM detects a failed brake switch. The EBCM sends a serial data message to the IPC requesting this display. A DTC sets when this condition exists. |
| • | VSES sensor initialization time is excessive. The EBCM sends a serial data message to the IPC requesting this display. |
| • | Serial data communication between the EBCM and any of several other control modules is interrupted. The EBCM sends a serial data message to the IPC requesting this display or the IPC displays the message when communication with the EBCM is interrupted. |
| • | The PCM is not able to perform engine torque reduction. The EBCM sends a GMLAN message to the IPC requesting this display. DTCs set when this condition exists. |
| • | The EBCM detects an excessively low or excessively high ignition voltage. The EBCM sends a GMLAN message to the IPC requesting this display. |
Vehicle Stability Enhancement System (VSES)
The desired yaw rate is calculated by the EBCM using, primarily, the following inputs.
| • | The position of the steering wheel |
| • | The speed of the vehicle |
| • | The lateral, or sideways acceleration of the vehicle |
The difference between the desired yaw rate and the actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. When a yaw rate error is detected, the EBCM attempts to correct the vehicle’s yaw motion by applying brake pressure to one or more of the wheels. The amount of brake pressure which is applied varies, depending on the correction required. The engine torque may be reduced also, if it is necessary to slow the vehicle while maintaining stability.
VSES activations generally occur in turns during aggressive driving. When braking during VSES activation, the pedal may pulsate. The brake pedal pulsates at a higher frequency during VSES activation than during ABS activation.
VSES Sensors Initialization
The following VSES sensors require initialization:
| • | The lateral accelerometer |
| • | The master cylinder pressure sensor |
| • | The steering wheel position sensor |
When the vehicle speed is greater than 25 km/h (15 mph), full sensor initialization must occur during 3 km (1.8 mi) of driving or 1 km (0.6 mi) of straight and stable driving, whichever occurs first. Although an attempt at initialization may fail due to driving conditions, such as driving on a very winding road, failed initialization is usually caused by a sensor bias voltage which is not within an acceptable range. Often, a DTC sets soon after a failed initialization attempt. The message center displays the stability system disabled message when sensor initialization fails.
Keep getting a ‘stabiliTrak service and service traction’ error message. The ‘brake pedal sensor switch’ has been replaced and now the message appears only when the engine is idling for more than a few minutes (disappears once I start driving). What could cause the message to keep appearing?
If equipped, this warning light should come on briefly when the engine is started.
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