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 IPC circuit board based upon IPC programming and electronic messages received by the IPC from the ABS module and the TCM over the CAN data bus.

The ESC indicator LED is completely controlled by the IPC logic circuit, and that logic will only allow this indicator to operate when the IPC 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 IPC transistor. Each time the ignition switch is turned to the ON position the ESC indicator is illuminated for about four seconds as a bulb test. The IPC will turn ON the ESC indicator for the following reasons:

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

The ABS module continually monitors the ESC circuits and sensors to decide whether the system is in good operating condition and the proper outputs to the components of the system. The ABS module then sends the proper lamp-ON or lamp-OFF message to the IPC.