The 5 inputs to the 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 PWM inputs. The EBCM must detect valid inputs from all 5 sources during the initialization period in order to enable the VSES. Initialization must occur during the first 3000 meters of vehicle travel or 1000 meters of straight vehicle travel. If initialization cannot be achieved during this time period, the VSES remains inactive and the message center displays the Stability System Disabled message. The EBCM does not attempt to reinitialize until the next ignition cycle.

During aggressive driving conditions which repeatedly activate the VSES, one or more of the solenoid coils may become overheated. The message center may display the Stability System Limited message at this time as the EBCM reduces VSES activation in an attempt to decrease the solenoid temperatures. If the temperature of any of the solenoids exceeds 275°C (527°F), the message center displays the Stability System Disabled message and the VSES becomes inactive. Coil temperatures are estimated by the EBCM based on ambient temperature and monitored solenoid activation and may not coincide with actual solenoid temperatures. The Stability System Disabled message turns OFF and VSES activity resumes when the EBCM determines the solenoids have cooled sufficiently.

If the customer's 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.

The VSES solenoid coils may overheat during aggressive driving. The Stability System Limited message is usually displayed prior to the Stability System Disabled message in the case of overheating solenoid coils.

A medium-low brake fluid level in the master cylinder reservoir may cause the Stability System Disabled message to be displayed during stopping or turning maneuvers. This condition will also cause the red brake warning indicator to turn ON. Ensure the master cylinder reservoir has an adequate brake fluid level.

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

The numbers below refer to the step numbers on the diagnostic table.

4. This step verifies that the yaw rate sensor signal voltage is within normal operating range. Voltage outside the specified range prevents VSES initialization.

5. This step verifies that the lateral accelerometer signal voltage is within normal operating range. Voltage outside the specified range prevents VSES initialization.

6. This step verifies that the master cylinder pressure sensor signal voltage is within normal operating range. Voltage outside the specified range prevents VSES initialization. If you completed steps 1 through 7 and did not locate the malfunction, you must have overlooked something.