ESC Indicator

The Electronic Stability Control (ESC) indicator gives an indication to the vehicle operator when the ESC system has been activated. This indicator is controlled by a transistor on the CCN circuit board based upon programming and electronic messages received from the Controller Antilock Brake (CAB) and the All-Wheel Drive Control Module (AWDCM) over the CAN data bus. The CCN will illuminate the ESC indicator for about four seconds each time the ignition is turned to the ON position, during the bulb test.

The ESC indicator LED is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the LED will always be OFF when the ignition switch is in any position except ON or START. The LED only illuminates when it is provided a path to ground by the instrument cluster transistor. The CCN will illuminate the ESC indicator for the following reasons:

• ESC Indicator Lamp-ON Message  - Each time the cluster receives an electronic ESC indicator lamp-ON  message from the CAB indicating that the ESP/BAS system has been activated, the ESP/BAS indicator will be illuminated. The indicator remains illuminated until the cluster receives a lamp-OFF message from the CAB, or until the ignition switch is turned to the OFF position, whichever occurs first.
• ESC Deactivated Textual Message  - Each time the cluster receives an electronic ESC OFF indicator lamp-ON  message from the CAB indicating that the ESP/BAS system has been manually disabled, an ESC Deactivated  textual message will appear within the cluster odometer display. The ESC Deactivated  textual message remains displayed until the cluster receives a lamp-OFF message from the CAB, or until the ignition switch is turned to the OFF position, whichever occurs first.

The CAB continually monitors the ESP/BAS circuits and sensors to decide whether the system is in good operating condition and the proper outputs to the components of the system. The CAB then sends the proper lamp-ON or lamp-OFF message to the CCN.

For proper diagnosis of the ESP/BAS system, the CAB, the AWDCM, the CCN the CAN data bus or the electronic communication related to the ESP/BAS indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.