Electronic Engine Controls

The electronic engine controls consist of the following:

• Powertrain control module (PCM)
• Cylinder head temperature (CHT) sensor
• Camshaft position (CMP) sensor
• Crankshaft position (CKP) sensor
• Mass air flow (MAF) sensor
• Heated oxygen sensor (HO2S)
• Catalyst monitor sensor (CMS)
• Knock sensor (KS)

The PCM:

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

The CHT sensor:

• sends the PCM a signal indicating cylinder head temperature.
• resistance decreases as coolant temperature increases. For additional information, refer to ELECTRONIC ENGINE CONTROLS - HYBRID article.

The CMP sensor:

• provides camshaft position information which is used by the PCM for fuel synchronization. For additional information, refer to ELECTRONIC ENGINE CONTROLS - HYBRID article.

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.
• sends the PCM a signal to determine the intake air mass. The PCM will then calculate the required fuel injector pulse width in order to provide the desired air/fuel ratio.

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:

• 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 KS:

• 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.