System Diagnosis
NOTE:
Before testing transmission, ensure fluid level is correct and throttle and shift cables are properly adjusted. Ensure engine starts with shift lever in Park and Neutral to ensure proper adjustment of Park/Neutral Position (PNP) switch. Transmission must first be tested for stored trouble codes. See RETRIEVING TROUBLE CODES .
The TCM monitors transmission operation and contains a self-diagnostic system which stores a trouble code if an electronic control system failure or problem is present. If a problem is present in the No. 1 or No. 2 shift solenoids and/or vehicle speed sensor, and a trouble code is present, the TCM will deliver a signal to flash OD OFF light on instrument panel to warn the driver.