Computer Controlled Shutdown

The PCM controls the PCM power relay when the ignition is turned to the ON or START position, by grounding the PCM relay control (PCMRC) circuit. After the ignition is turned to the OFF, ACC or LOCK position, the PCM stays powered up until the correct engine shutdown occurs.

The ignition switch position run (ISP-R) and the injector power monitor (INJPWRM) circuits provide the ignition state input to the PCM. Based on the ISP-R and INJPWRM signals the PCM determines when to power down the PCM power relay.