Electronic Engine Controls

The electronic engine controls consist of the following:
^ Powertrain Control Module (PCM)
^ Throttle Position (TP) sensor
^ Idle Air Control (IAC) valve
^ Camshaft Position (CMP) sensor
^ Crankshaft Position (CKP) sensor
^ Mass Air Flow (MAF) sensor
^ Intake Air Temperature (IAT) sensor
^ Heated Oxygen Sensor (HO2S)
^ catalyst monitor sensor
^ Knock Sensor (KS)
^ Cylinder Head Temperature (CHT) sensor
^ Power Steering Pressure (PSP) switch
^ fuel pressure sensor
^ Vehicle Speed Sensor (VSS)
^ Intake Manifold Tuning valve (IMT)

The PCM needs the following inputs to calibrate the engine correctly:
^ camshaft position
^ engine rpm
^ cylinder head temperature
^ clutch pedal position
^ amount of engine detonation
^ mass air flow (MAF) sensor

The throttle position sensor:
^ sends the PCM a signal indicating the throttle plate angle.
^ is the main input to the PCM from the driver.

The idle air control valve:
^ controls bypass air around the throttle plate at low speeds.
^ is controlled by the PCM.

The camshaft position sensor:
^ sends the PCM a signal indicating cam shaft position used for fuel synchronization and spark.

The power steering pressure switch:
^ monitors the outlet pressure of the power steering pump and is calibrated to both an actuation and release pressure setting.
^ increases the outlet pressure to match the severity of the turn maneuver.

The crankshaft position sensor:
^ sends the PCM a signal indicating crankshaft position.
^ is essential for calculating spark timing.

The mass air flow sensor:
^ sends the PCM a signal indicating mass air flow rate of air entering the engine.

The intake air temperature sensor:
^ sends the PCM a signal indicating the temperature of the air entering the engine.
^ resistance decreases as temperature increases.

The heated oxygen sensors:
^ monitor oxygen content before and after the exhaust flows through the catalytic converter.
^ provide a voltage to the PCM used to calculate catalytic converter integrity.

The knock sensor:
^ is located in the intake valley.
^ sends a signal to the PCM indicating engine detonation. (If detonation is occurring, the PCM then changes spark timing.)

The cylinder head temperature sensor:
^ is mounted into the wall of the cylinder head and is not connected to any coolant passages.
^ sends a signal to the PCM indicating the cylinder head temperature.
^ If the temperature exceeds approximately 121°C (250°F), the PCM disables half the fuel injectors at a time. The PCM will alternate which fuel injectors are disabled every 32 engine cycles. The cylinders that are not being fuel injected act as air pumps to aid in cooling the engine.
^ If the temperature exceeds approximately 166°C (330°F), the PCM disables all of the fuel injectors until the engine temperature drops below approximately 154°C (310°F).
^ The coolant temperature gauge pointer will read fully hot.
^ The check gauge warning indicator will illuminate and DTCs are set.

The fuel pressure sensor:
^ sends the PCM a signal indicating fuel pressure.
- The PCM uses the fuel pressure sensor signal and the fuel temperature sensor signal to maintain the fuel liquid pressure in the fuel line which reduces the fuel vapor pressure in the fuel line.

The vehicle speed sensor:
^ sends a frequency signal to the PCM.
- The PCM uses the vehicle speed sensor signal to calculate vehicle speed and to determine shift scheduling and electronic pressure control.

The intake manifold tuning valve:
^ connects the plenums to improve upper rpm power.