Electronic Engine Controls

The electronic engine controls consist of the following:

• powertrain control module (PCM)
• cylinder head temperature (CHT) sensor (2.3L)
• engine coolant temperature (ECT) sensor (3.0L)
• throttle position (TP) sensor
• idle air control (IAC) valve
• camshaft position (CMP) sensor
• crankshaft position (CKP) sensor
• mass air flow (MAF) sensor
• heated oxygen sensor (HO2S)
• catalyst monitor sensor
• knock sensor (KS)
• intake manifold tuning valve (IMTV)

The PCM carries out the following functions:

• accepts input from various engine sensors to compute the fuel flow rate necessary to maintain a prescribed air/fuel ratio throughout the entire engine operational range.
• outputs a command to the fuel injectors to meter the appropriate quantity of fuel.

The CHT sensor (2.3L):

• sends the PCM a signal indicating cylinder head temperature.
• resistance decreases as coolant temperature increases.

The ECT sensor (3.0L):

• sends the PCM a signal indicating engine temperature.
• resistance decreases as coolant temperature increases.

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 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:

• uses a hot wire sensing element to measure the amount of air entering the engine. Air passing over the hot wire causes it to cool.

The HO2S:

• creates 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 KS (2.3L):

• is used to detect engine detonation.
• sends a voltage signal to the PCM.
• is able to provide a signal which retards the ignition timing, as necessary.