System Diagnosis

NOTE: The PCM On-Board Diagnostic (OBD) system check must be used as the starting point for any transmission electrical repairs. This will direct technician to the next logical step, save diagnostic time and prevent unnecessary replacement of functional components. See PCM ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK .

The PCM continuously monitors transmission operation and contains a self-diagnostic system which stores a Diagnostic Trouble Code (DTC) if an electronic control system problem or component failure is present. A 4-digit OBD-II DTC is used in the self-diagnostic system for diagnosis. OBD-II DTC is stored in the Powertrain Control Module (PCM) and illuminates the Malfunction Indicator Light (MIL) when set. If OD/OFF indicator or MIL indicates a system malfunction, retrieve DTC using desired method. See RETRIEVING TROUBLE CODES .