Electronic Engine Controls
Electronic Engine Controls
The electronic engine controls consist of the:
- PCM.
- Cylinder Head Temperature (CHT) sensor.
- Camshaft Position (CMP) sensor.
- Crankshaft Position (CKP) sensor.
- Heated Oxygen Sensor (HO2S).
- Catalyst Monitor Sensor (CMS).
- Variable Camshaft Timing (VCT) oil control solenoid.
- Knock Sensor (KS).
- Mass Air Flow (MAF) sensor (except Gasoline Turbocharged Direct Injection (GTDI) engines).
- Throttle Position (TP) sensor (GTDI (Gasoline Turbocharged Direct Injection) engines only).
- Fuel Rail Pressure (FRP) sensor (GTDI (Gasoline Turbocharged Direct Injection) engines only).
- Intake Air Temperature (IAT) sensor (GTDI (Gasoline Turbocharged Direct Injection) engines only).
- Turbocharger Boost Pressure (TCBP) /Charge Air Cooler Temperature (CACT) sensor (GTDI (Gasoline Turbocharged Direct Injection) engines only).
- Manifold Absolute Pressure (MAP) /Intake Air Temperature 2 (IAT2) sensor (GTDI (Gasoline Turbocharged Direct Injection) engines only).
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 (Cylinder Head Temperature) sensor:
- sends the PCM a signal indicating cylinder head temperature.
- resistance decreases as cylinder head temperature increases.
The CMP (Camshaft Position) sensor:
- sends the PCM a signal indicating camshaft position used for fuel synchronization.
The CKP (Crankshaft Position) sensor:
- sends the PCM a signal indicating crankshaft position.
- is essential for calculating spark timing.
The HO2S (Heated Oxygen Sensor) :
- creates a voltage signal dependent on exhaust oxygen content.
- provides feedback information to the PCM used to calculate fuel delivery.
The CMS (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 VCT (Variable Camshaft Timing) 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 (Knock Sensor) :
- 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 MAF (Mass Air Flow) 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 TP (Throttle Position) sensor:
- sends the PCM a signal indicating the throttle plate angle.
- is the main input to the PCM from the driver.
The FRP (Fuel Rail Pressure) sensor:
- measures the pressure of the fuel rail and sends these signals to the PCM.
The IAT (Intake Air Temperature) sensor:
- sends the PCM a signal indicating the temperature of the air entering the engine.
The TCBP (Turbocharger Boost Pressure) /CACT (Charge Air Cooler Temperature) sensor:
- is a combination sensor.
- measures turbocharger boost pressure and sends this information to the PCM.
- measures the temperature of the charge air exiting the turbocharger compressor and sends this information to the PCM.
The MAP (Manifold Absolute Pressure) /IAT2 (Intake Air Temperature 2) sensor:
- is a combination sensor.
- measures manifold vacuum and converts it to an electrical signal. This provides the PCM information on engine load.
- sends the PCM a signal indicating the temperature of the air entering the cylinders after passing over the Charge Air Cooler (CAC).