ESC Off Indicator

The ESC OFF indicator gives an indication to the vehicle operator that the ESP system has been manually disabled. 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 OFF indicator function of the odometer VFD unit 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 VFD ESC OFF indication will always be OFF when the ignition switch is in any position except ON or START. The IPC will turn ON the ESC OFF indicator for the following reasons:

• ESC OFF Indicator Lamp-On Message  - Each time the IPC receives an electronic ESC OFF indicator lamp-ON  message from the ABS module indicating that the ESP system has been manually disabled by depressing the ESC OFF switch button in the instrument panel switch pod, the ESC OFF 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.

The IPC continually monitors the status of the ESC OFF switch over a LIN data bus circuit to determine the requested operating mode for the ESC system. The IPC then sends an electronic ESC OFF switch status message  to the ABS module over the CAN data bus. The ABS module then sends the proper lamp-ON or lamp-OFF message back to the IPC, confirming the current operating mode of the ESC system.