Electronic Engine Controls: Notes

The 2.0L GTDI  electronic engine controls consist of the:

• PCM.
• Cylinder Head Temperature (CHT) sensor.
• Camshaft Position (CMP) sensor.
• Crankshaft Position (CKP) sensor.
• Intake Air Temperature (IAT) sensor.
• Manifold Absolute Pressure (MAP) sensor.
• Manifold Absolute Pressure and Temperature (MAPT) sensor.
• Heated Oxygen Sensor (HO2S).
• Catalyst Monitor Sensor (CMS).
• Variable Camshaft Timing (VCT) oil control solenoid.
• Fuel Rail Pressure (FRP) sensor.
• Knock Sensor (KS).
• Engine Coolant Temperature (ECT) sensor.
• Turbocharger bypass valve solenoid
• Turbocharger wastegate regulating valve solenoid
• Wastegate vacuum sensor
• Wastegate actuator
• Filter and cover

The 3.5L and 3.7L electronic engine controls consist of the:

• 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).
• Variable Camshaft Timing (VCT) oil control solenoid.
• 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 operational 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 cylinder head 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  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 CMS  :

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

The VCT  oil control solenoid:

• is an electrically controlled hydraulic valve that directs engine oil to the variable camshaft. Once the PCM transmits a signal, the solenoid moves a valve spool, directing oil into the camshaft phaser cavity. This action changes valve timing by either inducing an advance or retard condition. The camshaft is, thereby repositioned in relation to crankshaft timing and allows for optimum engine performance and lower emissions.

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.

The IAT  sensor - 2.0L GTDI  :

• measure the temperature of the air leaving the ACL  .

The Manifold Absolute Pressure (MAP) sensor - 2.0L GTDI  :

• it senses engine load.
• generates a signal that is proportional to the amount of vacuum in the intake manifold

The Manifold Absolute Pressure and Temperature (MAPT) sensor - 2.0L GTDI  :

• provide precise measurements of manifold absolute pressure and manifold air temperature.

The Fuel Rail Pressure (FRP) sensor - 2.0L GTDI  :

• measures the pressure of the fuel rail and sends these signals to the PCM.

The Engine Coolant Temperature (ECT) sensor - 2.0L GTDI  :

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

The turbocharger bypass valve solenoid - 2.0L GTDI  :

• is electro-pneumatically controlled and is integrated into the turbocharger housing
• prevents backflow through the turbocharger when the throttle is rapidly closed to avoid undesirable noise.

The turbocharger wastegate regulating valve solenoid - 2.0L GTDI  :

• supplies pressure or vacuum to the pneumatically powered wastegate, regulating boost pressure.
• allows the PCM to indirectly control the wastegate.

The wastegate vacuum sensor - 2.0L GTDI  :

• measures the vacuum supplied by the wastegate regulating valve solenoid to the wastegate actuator.
• provides the PCM an analog output voltage.

The wastegate actuator - 2.0L GTDI  :

• can be driven using vacuum or pressure depending on the application.
• mechanically opens or closes the wastegate valve to control boost pressure.

The filter and cover - 2.0L GTDI  :

• protects the vacuum supply from contamination.