Entering & Exiting Diagnostic Mode
To enter diagnostic mode, use scan tool. With ignition on and engine off, connect a scan tool to Data Link Connector (DLC) located behind left side of dash. See Fig 1. The Diesel Electronic Control (DEC)/electronically-controlled transmission systems will enter diagnostic mode. In this mode, PCM/TCM will display DTCs on scan tool. Refer to scan tool instructions provided by manufacturer for further information. To exit diagnostic mode, turn ignition off and remove scan tool from DLC.