Perform Service Indicator - Operation

OPERATION

The perform service indicator gives an indication to the vehicle operator when the service distance (kilometers or miles to service) setting becomes zero. This indicator is controlled by the instrument cluster logic circuit based upon cluster programming and electronic messages received by the cluster from the Powertrain Control Module (PCM) over the Controller Area Network (CAN) data bus.

The perform service indicator function of the reconfigurable dot matrix Organic Light Emitting Diode (OLED) display unit 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 OLED perform service indication will always be OFF when the ignition switch is in any position except ON or START. The instrument cluster will turn ON the perform service indicator for the following reasons:

- Kilometers Or Miles To Service calculation Equals Zero - The target service distance is set using the customer programmable features function of the Electronic Vehicle Information Center (EVIC). The cluster subtracts the current odometer distance reading from the target service distance setting to compute the kilometers or miles to service. Each time the ignition switch is turned to the ON position and the cluster calculates that the kilometers or miles to service equals zero, the perform service indicator will be illuminated. The indicator remains illuminated for about three seconds, until the EVIC target service distance is reset, until the cluster arbitrator logic determines that another display request has priority, or until the ignition switch is turned to the OFF position, whichever occurs first.

The PCM continually monitors the vehicle speed pulse information received from the wheel speed sensors, then sends the proper distance messages to the instrument cluster, also known as the Cab Compartment Node (CCN) over the CAN data bus. The CCN continually compares the displayed odometer distance to the target service distance setting to determine the kilometers or miles to service, then controls the perform service indicator as appropriate.

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