Electronic Engine Controls

The electronic engine controls consist of the following:

• Powertrain Control Module (PCM)
• Throttle Position (TP) Sensor
• Idle Air Control (IAC) Valve
• Engine Coolant Temperature (ECT) Sensor - 3.0L (4V)
• Cylinder Head Temperature (CHT) Sensor - 2.0L Zetec
• Camshaft Position (CMP) Sensor
• Crankshaft Position (CKP) Sensor
• Mass Air Flow (MAF/IAT) Sensor
• Intake Air Temperature (IAT) Sensor
• Heated Oxygen Sensor (HO2S)
• Catalyst Monitor Sensor
• Power Steering Pressure (PSP) Switch - 3.0L (4V)
• Knock Sensor (KS) 2.0L Zetec
• Clutch Pedal Position (CPP) Switch

The PCM needs the following inputs to calibrate the engine correctly:

• Crankshaft Position
• Camshaft Position
• Engine RPM
• Engine Load
• Engine Coolant Temperature
• Mass Air Flow
• Amount Of Engine Detonation

The TP sensor:

• Sends the PCM a signal indicating throttle plate angle.
• Is the main input to the PCM from the driver.
• On the 2.0L Zetec is not repaired separately from the throttle body.

The IAC valve:

• Controls bypass air around the throttle plate at low speeds.
• Is controlled be the PCM.

The ECT sensor:

• Sends the PCM a signal indicating engine temperature.
• Resistance decreases as coolant temperature increases.

The CHT sensor:

• Sends the PCM a signal indicating the cylinder head temperature.
• Resistance decreases as coolant temperature increases.

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/IAT sensor:

• Sends the PCM a signal indicating mass air flow rate of air entering the engine.

The IAT sensor:

• Sends the PCM a signal indicating the temperature of the air entering the engine.
• Is incorporated into the MAF/IAT sensor and is repaired as an assembly.

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 sensor:

• Monitors oxygen content after it flows through the catalytic converter.
• Provides a voltage to the PCM used to calculate catalytic converter integrity.

The PSP switch:

• Sends a signal to the PCM to increase idle speed for engine stability when power steering pump pressure increases above a set pressure value.

The KS:

• Sends a signal to the PCM indicating engine detonation, which retards the ignition timing as necessary.

The CPP switch:

• Is mounted on the clutch pedal bracket.
• Sends a signal to the cruise control amplifier to disengage the cruise control system when the clutch pedal is depressed.