Electronic Engine Controls
WARNING: This page is about a different car, the 2005 Mercury Montego, 2005 Ford Freestyle, and 2005 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.
The electronic engine controls consist of the following:
- Power control module (PCM)
- Engine coolant temperature (ECT) sensor
- Camshaft position (CMP) sensor
- Fuel rail pressure and temperature sensor
- Crankshaft position (CKP) sensor
- Mass air flow (MAF) sensor
- Heated oxygen sensor (HO2S)
- Catalyst monitor sensor
- Knock sensor (KS)
The PCM:
- accepts input from various engine sensors to compute the fuel flow rate necessary to maintain a prescribed air/fuel ratio throughout the entire engine operational range.
- outputs a command to the fuel injectors to meter the appropriate quantity of fuel.
The ECT sensor:
- sends the PCM a signal indicating engine temperature.
- resistance decreases as coolant temperature increases.
The CMP sensor:
- provides camshaft position information which is used by the PCM for fuel synchronization.
The fuel rail pressure and temperature sensor:
- measures the pressure and temperature of the fuel in the fuel supply manifold and sends these signals to the PCM.
- uses intake manifold vacuum as a pressure reference.
The CKP sensor:
- sends the PCM a signal indicating crankshaft position.
- is essential for calculating spark timing.
The MAF sensor:
- uses a hot wire sensing element to measure the amount of air entering the engine. Air passing over the hot wire causes it to cool.
The HO2S:
- creates a voltage signal dependent on exhaust oxygen content.
- provides feedback information to the PCM used to calculate fuel delivery.
The catalyst monitor sensor:
- monitors oxygen content after it flows through the catalytic converter.
- provides a voltage to the PCM used to calculate catalytic converter integrity.
The KS:
- is used to detect engine detonation (spark knock).
- sends a voltage signal to the PCM which retards the ignition timing as necessary.