Powertrain Control Module

The Powertrain Control Module (PCM) monitors its input/output signals (some signals all the time and others under specified conditions). When an irregular signal is initially monitored, the PCM decides that a malfunction has occurred and records the occurrence as a Diagnostic Trouble Code (DTC). There are 26 diagnostic items. The diagnostic results can be read with a scan tool. DTCs are kept in memory by direct battery feed. The DTCs are retained in memory even if the ignition is off. DTCs will be erased when a battery terminal or a PCM harness connector is disconnected. In addition, the DTC can also be erased by the scan tool. If a sensor is disconnected when the ignition is on, a DTC is memorized. In this case, erase the DTC using the scan tool. The 26 diagnostic items are displayed in numeric order. See SELF-DIAGNOSTIC SYSTEM  .