Electronic Engine Controls

The electronic engine controls consist of the:

• 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.