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) - front
- Catalyst monitor sensor-rear
- Knock sensor (KS)
- Fuel rail pressure (FRP) sensor
- Cylinder head temperature (CHT) sensor
- Engine coolant temperature (ECT) sensor
- Intake manifold runner control (IMRC) actuator
- Output shaft speed (OSS) sensor
The PCM needs the following inputs to calibrate the engine correctly:
- Air temperature
- Throttle position
- Crankshaft position
- Camshaft position
- Engine rpm
- Cylinder head temperature
- Amount of engine detonation
- Engine coolant temperature
- Mass air flow
- Fuel rail pressure
The TP sensor:
- Sends the PCM a signal indicating the throttle plate angle.
- Is the main input to the PCM from the driver.
The IAC valve:
- Controls bypass air around the throttle plate at low speeds.
- Is controlled by the PCM.
The ECT sensor:
- Provides the PCM a signal for coolant temperature.
- Is mounted on top of the lower intake manifold.
The CMP sensor:
- Sends the PCM a signal indicating camshaft position used for fuel synchronization.
The CKP sensor:
- Sends the PCM a signal indicating crankshaft position.
- Is essential for calculating spark timing.
The MAF sensor:
- Sends the PCM a signal indicating the temperature of the air entering the engine.
- Sends the PCM a signal indicating mass air flow rate of air entering the engine.
The IAT sensor:
- Is repaired as an assembly with the MAF sensor.
The HO2S:
- Has the ability to create a voltage signal dependent on exhaust oxygen content.
- Provides feedback information to the PCM used to calculate fuel delivery.
The catalyst monitor oxygen sensors:
- Monitor oxygen content after the catalytic converter.
- Provide a voltage to the PCM used to calculate catalytic converter integrity.
The fuel rail pressure (FRP) sensor:
- Measures the pressure of the fuel in the fuel injection supply manifold and sends a signal to the PCM.
- Uses intake manifold vacuum as a pressure reference.
The knock sensor (KS):
- Is located in the intake valley (4.6L/5.4L/6.8L).
- Sends a signal to the PCM indicating engine detonation.
The CHT sensor:
- Is mounted into the back of the left 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 (260 °F), the PCM disables some fuel injectors. The PCM will alternate which fuel injectors are disabled every 24 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 124°C (260 °F).
The OSS sensor:
- Is gear driven by the transmission.
- Sends a signal to the PCM indicating transmission output shaft speed. For additional information, refer to AUTOMATIC TRANSAXLE/TRANSMISSION-4R100 or AUTOMATIC TRANSAXLE/TRANSMISSION - 4R70W/4R75W .