Computer Controlled Shutdown

The powertrain control module (PCM) controls the electronic engine control (EEC) power relay when the ignition key is turned to the ON or START position, by grounding the PCM relay control (PCMRC) circuit. After the ignition key is turned to the OFF, ACC or LOCK position, the PCM will stay powered up until the proper engine shutdown occurs.

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