Computers and Control Systems: Description and Operation

The electronic engine controls consist of the:
- Powertrain Control Module (PCM).
- Throttle Position sensor (TP sensor).
- Idle Air Control valve (IAC valve).
- Engine Coolant Temperature sensor (ECT sensor).
- Camshaft Position Sensor (CMP sensor)
- Camshaft synchronizer.
- Crankshaft Position Sensor (CKP sensor).
- Mass Air Flow sensor (MAF sensor).
- Intake Air Temperature sensor (IAT sensor).
- Heated Oxygen Sensor (HO2S).
- Vehicle Speed Sensor (VSS).
- Cylinder Head Temperature (CHT) sensor.

The powertrain control module needs the following inputs to calibrate the engine properly:
- camshaft position.
- engine rpm.
- engine coolant temperature.
- amount of engine detonation.

The throttle position sensor:
- sends the powertrain control module a signal indicating the throttle plate angle.
- is the main input to the powertrain control module from the driver.

The engine coolant temperature sensor:
- sends the powertrain control module a signal indicating engine temperature.
- resistance decreases as coolant temperature increases.

The camshaft position sensor:
- sends the powertrain control module a signal indicating camshaft position. The signal is used for fuel synchronization.

The crankshaft position sensor:
- sends the powertrain control module a signal indicating crankshaft position.
- is essential for calculating spark timing.

The mass air flow sensor:
- sends the powertrain control module a signal indicating mass airflow rate of air entering the engine.

The intake air temperature sensor:
- sends the powertrain control module a signal indicating the temperature of the air entering the engine.
- resistance decreases as temperature increases.

The heated oxygen sensor:
- has the ability to create a voltage signal dependent on exhaust oxygen content.
- provides feedback information to the powertrain control module used to calculate fuel delivery.

The knock sensor is located on the RH side of the block.
- sends a signal to the powertrain control module indicating engine detonation.
- if detonation is occurring, the powertrain control module then changes engine timing.

The vehicle speed sensor:
- is gear driven by the transmission.
- sends a signal to the powertrain control module indicating vehicle speed.

The Clutch Pedal Position (CPP) switch:
- sends a signal to the powertrain control module indicating clutch pedal position.