CIRCUIT DESCRIPTION:
Filter Life Monitor (FM) is a part of OEM 5th Generation Prognostics functionality. When enabled in the TCM, prognostic logic determines control main filter life based on hours accumulated and vehicle mileage. This information is used to determine the remaining control main filter useable life. When the TCM determines the filter life has degraded, a J1939 message is sent to a dash mounted SERVICE TRANS indicator lamp. A flashing SERVICE TRANS indicator lamp informs the driver that the transmission control main filter should be serviced. If the SERVICE TRANS indicator lamp is ignored for 100 hours, a CHECK TRANS light illuminates and DTC P088B sets.

ACTION TAKEN WHEN THE DTC SETS:
1. The CHECK TRANS light is illuminated.
2. The TCM forces Variable Modulated Main off.
3. DTC P088B is stored in the TCM history.

CONDITIONS FOR CLEARING THE DTC:
Replace the Control Main Filter. Use the diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes 40 warm-up cycles without failure.

DIAGNOSTIC AIDS:
This function can also be reset by turning on the ignition and selecting N (Neutral)-R (Reverse )-N (Neutral)-R (Reverse)-N (Neutral)-D (Drive)-N (Neutral).