Diesel Engine Management System
Accelerator Pedal Position (APP) Sensor
As the accelerator pedal position changes, the sensor varies the signal voltage to the ECM.
Air Conditioning (A/C) Compressor Clutch Relay
When the engine control module (ECM) receives a demand for cooling from the A/C system, it delays the compressor from being energized, and enriches the mixture to assure smooth transition to the A/C mode.
The alternator signals the ECM during charging.
Barometric Pressure (BARO) Sensor
The BARO sensor is inside the ECM. It converts atmospheric pressure into a voltage signal that modifies the basic duration of the fuel injection discharge.
Brake Pedal Position Switch
The brake pedal position switch signals the ECM when the brake pedal is pressed.
Camshaft Position (CMP) Sensor
The CMP sensor detects the angle of camshaft as a reference for sequential fuel injection to each cylinder.
Crankshaft Position (CKP) Sensor
The CKP sensor detects engine speed and determines ignition timing and timing for fuel injection of each cylinder.
Engine Coolant Temperature (ECT) Sensor
The ECT sensor is a temperature dependent resistor (thermistor). The resistor of the thermistor decreases as the engine coolant temperature increases.
Intake Air Temperature/Manifold Absolute Pressure (IAT/MAP) Sensor
The IAT sensor is a temperature dependant resistor (thermistor). The resistance of the thermistor decreases as the intake air temperature increases.
The MAP sensor converts manifold absolute pressure into electrical signals to the ECM.
Mass Air Flow (MAF) Sensor
The MAF sensor contains hot wire and a thermistor. It is located in the intake air passage. The resistance of the hot wire and thermistor change due to intake air temperature and air flow. The control circuit in the MAF sensor controls the current to keep the hot wire at a set temperature. The current is coverted to voltage in the control circuit, then output to the ECM.
Because the vacuum is not produced on the diesel engine, the vacuum pump is driven by the cam chain to produce the vacuum.