What Does the PCM in a 1991-94 Mercury Capri Do?
The Powertrain Control Module (PCM) is actually a computer for the 1991-94 Mercuy Capri model and is located under the dash in the center. It plays a vital roll in your car's performance and general operation.
The PCM detects engine operating and driving conditions and exxhaust gas oxygen content from various sensors and switches. It then controls the amount of fuel injected into the engine. The PCM also has control of the evaporative emissions, idle air control, ignition and deceleration systems.
PCM outputs are: fuel injector, ac relay, fuel pump, canister purge solenoid, idle air control valve, ignition control module and fuel pressure regulator control.
PCM inputs are: intake air temp sensor, battery, overboost pressure for turbo, ignition switch, air flow meter, throttle sensor, power steering swtich, ECT sensor, barometric pressure sensor, clutch pedal sensor, oxygen sensor, brake switch, electrical load unit and manual lever position.
In short, if the PCM fails, your car will have serious problems.