Engine - Engine Attaching Parts
Engine Control Module
The engine control module (ECM) operates a closed loop emission control system that precisely controls the air-fuel ratio, allowing the use of a three-way catalyst to control emissions of oxides of nitrogen to oxidize hydrocarbons and carbon monoxide.
The ECM receives a signal from the heated oxygen sensor (HO2S) in the exhaust manifold and generates the appropriate control signal for the fuel injectors. It also provides the ignition timing control signal, and control signals for the following:
- Vacuum switching valve (VSV) for the evaporative emission (EVAP) canister purge.
- VSV for the fuel pressure control valve.
- VSV for the secondary air injection air management valve.
The ECM receives input signals from:
- Mass air flow sensor (hot wire) at air intake.
- Crankshaft position sensor.
- Vehicle speed sensor.
- Engine coolant temperature sensor.
- Wide open throttle (WOT) switch.
- Heated oxygen sensor in the exhaust.
An air regulator valve provides an air bleed to the intake manifold to improve starting and warm up in cold conditions.
The minimum fuel octane rating is now 87.