Stability System Not Ready Indicator Always On

Stability System Not Ready Indicator Always On

Circuit Description

The 5 inputs to the electronic brake control module (EBCM), which are used solely for vehicle stability enhancement, are the longitudinal accelerometer, lateral accelerometer, yaw rate sensor, master cylinder pressure sensor, and the steering wheel position sensor. The EBCM must detect valid inputs from all 5 sources during the initialization period in order to enable the vehicle stability enhancement system (VSES). Initialization must occur during the first 3,000 meters of vehicle travel or 1,000 meters of straight vehicle travel. If initialization cannot be achieved during this time period, the VSES remains inactive and the stability system not ready indicator is illuminated. The EBCM does not attempt to reinitialize until the next ignition cycle. One or more DTCs often set, shortly after an unsuccessful initialization attempt, indicating the root cause of the failure. If this occurs, the stability system not ready indicator is no longer illuminated. The stability system caution indicator is illuminated instead.

Diagnostic Aids

If the customer concern is that the stability system disabled message is displayed intermittently, communicate with the customer to determine what driving conditions are being experienced at the time the message is displayed. The EBCM may be unable to successfully initialize the system during operation on very winding roads. Initialization may also be unsuccessful if pressure is continuously applied to the brake pedal during the initialization period.

If the message is displayed due to any of the above conditions, no diagnosis or repair of the VSES is required.

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