Powertrain Control Module (Pcm)

One PCM controls ignition system and another PCM controls fuel system. Electronic Fuel Injection (EFI) PCM is located inside right side of trunk, behind trim panel. Digital Ignition System (DIS) PCM is located under right side of instrument panel. EFI PCM is a digital PCM with an integral manifold pressure sensor, which governs the amount of fuel to be injected by controlling injector pulse width. Manifold pressure and speed signal provide the main control for fuel injection. PCM uses additional sensors to monitor engine temperature, inlet air temperature and throttle position to ensure optimum air/fuel mixture is computed for all engine operating conditions.

A microprocessor located within DIS PCM controls timing of low tension voltage by means of 2 ignition coils and 2 power modules. Front coil supplies high tension voltage to "B" bank (left cylinder head) and rear coil supplies high tension voltage to "A" bank (right cylinder head). PCM controls ignition timing according to inputs received from sensors located on and around engine. System is equipped with a limp-home mode to permit continued engine operation in case of certain sensor failures.

NOTE: Components are grouped into 2 categories. The first category covers INPUT DEVICES, which control or produce voltage signals monitored by the PCM. The second category covers OUTPUT SIGNALS, which are components controlled by the PCM.