Change Oil Indicator

The change oil indicator gives an indication to the vehicle operator when a duty-cycle algorithm contained within the software of the PCM determines that a recommended oil change interval has been attained. This indicator is controlled by the IPC logic circuit based upon IPC programming and electronic messages received over the CAN data bus from the PCM.

The change oil indicator function of the odometer or EVIC 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 odometer or EVIC VFD change oil indication will always be OFF when the ignition switch is in any position except ON or START. The IPC will turn ON the change oil indicator for the following reasons:

• Change Oil Indicator Lamp-On Message  - Each time the ignition switch is turned to the ON position and the IPC receives an electronic change oil indicator lamp-ON  message from the PCM indicating that a duty-cycle based recommended oil change interval has been attained, the change oil indicator will be illuminated for about three seconds, until the trip odometer reset switch button or an EVIC steering wheel switch button is depressed, or until the ignition switch is turned to the OFF position, whichever occurs first.
• Change Oil Indicator Reset Procedure  - Once an engine oil change has been completed, the PCM duty cycle counters can be reset using the following procedure. Turn the ignition switch to the ON position, but DO NOT start the engine. Slowly depress and release the accelerator pedal fully three times within ten seconds. Turn the ignition switch to the OFF position. If the change oil indicator illuminates the next time the engine is started, repeat this procedure.

The PCM continually monitors numerous sensor inputs to determine the duty-cycles to which the engine is being subjected. A pre-programmed algorithm within the PCM then determines when to send the proper lamp-ON or lamp-OFF message to the IPC.