Electronic Engine Controls

Electronic Engine Controls

The electronic engine controls consist of the following:

- PCM
- Accelerator Pedal Position (APP) sensor
- Throttle Position (TP) sensor
- Cylinder Head Temperature (CHT) sensor
- Camshaft Position (CMP) sensor mounted to the LH side of the front cover on 4.6L (2V) engines, mounted on each side of the front cover on 4.6L (3V) and 5.4L (3V) engines and mounted on the inside rear of each cylinder head on 6.2L (2V) engines.
- Crankshaft Position (CKP) sensor mounted on the lower RH side of the engine block on 4.6L (2V), 4.6L (3V) and 5.4L (3V) engines and on the top rear of the engine block on 6.2L (2V) engines.
- Mass Air Flow (MAF) sensor
- Heated Oxygen Sensor (HO2S)
- Catalyst Monitor Sensor (CMS)
- Knock Sensor (KS)
- Vehicle Speed Sensor (VSS)

The PCM needs the following inputs in order for the engine to operate correctly:

- CMP
- Engine rpm
- CHT
- Amount of engine detonation
- CKP
- Air temperature
- TP
- Mass airflow
- Exhaust oxygen content

The APP sensor:

- sends the PCM a signal indicating pedal rotation angle.
- is the main input to the PCM from the driver.
- is serviced as part of the accelerator pedal. Refer to Fuel Delivery and Air Induction.

The TP sensor:

- sends the PCM a signal indicating the throttle plate angle.
- is incorporated into the electronic Throttle Body (TB).

The CHT sensor:

- is mounted to the wall of the cylinder head and is not connected to any coolant passages.
- sends the PCM a signal indicating CHT.
- As the CHT rises above normal operating temperature, the PCM will turn on the high-speed cooling fan. If the temperature continues to rise, the PCM will selectively and alternately disable fuel injectors. The cylinders that are not being fuel injected will act as air pumps to aid in engine cooling. The PCM will also turn on the check engine light and set a DTC. If the CHT continues to rise, the check engine light will begin to flash and an additional DTC will be set. Finally, if the CHT rises still more, the PCM disables all of the fuel injectors, turning the engine off.

The CMP sensor:

- sends the PCM a signal indicating CMP used for fuel synchronization.

The CKP sensor:

- sends the PCM a signal indicating CKP and engine speed.
- is essential for calculating spark timing.

The MAF sensor:

- sends the PCM a signal indicating mass airflow rate of air entering the engine.
- sends the PCM a signal indicating the temperature of the air entering the engine.

The HO2S:

- sends the PCM a signal indicating oxygen content in the exhaust before the exhaust enters the catalytic converter.
- provides feedback information to the PCM used to calculate fuel delivery.

The CMS:

- sends the PCM a signal indicating oxygen content in the exhaust after the exhaust leaves the catalytic converter to calculate catalytic converter integrity.

The KS:

- sends a signal to the PCM indicating engine detonation.

The VSS:

- is gear driven by the transmission.
- sends a signal to the PCM indicating vehicle speed. Refer to Automatic Transmission/Transaxle &/or Transmission Control Systems.