Oil Change Indicator - Operation

OPERATION

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

The change oil indicator function of the odometer or reconfigurable Vacuum Fluorescent Display (VFD) 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 odometer or reconfigurable VFD change oil indication will always be OFF when the ignition switch is in any position except ON or START. The instrument cluster 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 cluster 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 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 ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN).

For proper diagnosis of the change oil indicator, the PCM, the EMIC, the CAN data bus or the electronic communication related to change oil indicator operation a diagnostic scan tool is required. Refer to the appropriate diagnostic information.