Diagnosis And Testing

In the event of a transmission performance or shift quality concern, the transmission Control Module (TCM) has the capability of monitoring numerous transmission parameters and will record a DTC if an anomaly is detected. It is important to remember that if there are any engine performance issues or DTCs present, these should be repaired first in most cases prior to diagnosing the transmission. The symptom table below gives suggested items to check for in the event of a transmission performance complaint that is not accompanied by a DTC. This table is not all inclusive. In the event of a transmission performance complaint with no DTCs, it is imperative to duplicate the concern before attempting to repair the transmission by replacing any components. In all cases, check that the engine, battery and charging system is functioning correctly. Make sure the transmission fluid level is correct and that all transmission wiring is correctly routed, free from damage and that all connectors are in good condition and properly secured.