Information Sensors

Oxygen Sensors (HO2S) - The sensor generates a signal whose amplitude depends on the difference in oxygen (O₂) content between the engine exhaust gas and the outside air.
Crankshaft Position Sensor (CKP) - The sensor informs the PCM of the crankshaft position and engine speed. The processor uses this information to determine fuel injection timing and ignition timing.
Camshaft Position Sensor (CMP) - Based on the signals received from the sensor, the PCM calculates the position of the No. 1 cylinder piston and uses this information to determine the timing and sequence of fuel injection into the engine combustion chambers.
Top Dead Center Sensor (TDC) - The signals generated by the sensor are used by the PCM to determine ignition timing advance when starting the engine.
Engine Coolant Temperature Sensor (ECT) - Based on the information received from the sensor, the ECM/PCM makes the necessary corrections to the air-fuel mixture and ignition timing, and also monitors the operation of the EGR system.
Intake Air Temperature Sensor (IAT) - The PCM uses the information received from the IAT sensor to correct fuel flow, ignition timing advance, and to control EGR system operation.
Throttle Position Sensor (TPS) - The sensor is located on the throttle body and is connected to the throttle valve shaft. Based on the TPS signal amplitude, the PCM determines the throttle valve opening angle (controlled by the driver via the accelerator pedal) and adjusts the fuel supply to the intake ports of the combustion chambers accordingly. Sensor failure or loosening of its mounting leads to injection interruptions and unstable idle speed.
Manifold Absolute Pressure Sensor (MAP) - The sensor monitors variations in intake manifold vacuum associated with changes in crankshaft speed and engine load, and converts the received information into an amplitude signal. The PCM uses the information from the MAP and IAT sensors to make fine corrections to fuel delivery.
Barometric Pressure Sensor - The sensor generates an amplitude signal proportional to changes in atmospheric pressure, which the PCM uses to determine the duration of fuel injection pulses. The sensor is built into the PCM and is not serviced separately.
Knock Sensor - The sensor responds to changes in vibration level associated with engine knock. Based on the information received from the sensor, the PCM makes the corresponding correction to ignition timing.
Vehicle Speed Sensor (VSS) - As its name implies, the sensor informs the processor of the current vehicle speed.
EGR Valve Position Sensor - The sensor informs the PCM of the displacement of the EGR valve pintle. The processor then uses this information to control the exhaust gas recirculation system operation.
Fuel Tank Pressure Sensor - The sensor is a component of the Evaporative Emission (EVAP) control system and monitors fuel vapor pressure in the tank. Based on the information received from the sensor, the PCM issues commands to energize the purge control solenoid valves.
Power Steering Pressure Switch (PSP) - Based on the information received from the PSP switch, the PCM increases idle speed by actuating the IAC valve to compensate for increased engine loads associated with power steering operation during maneuvering.
Transmission Sensors - In addition to the data received from the VSS, the PCM also receives information from sensors located inside or connected to the transmission. These sensors include: (a) the output shaft (mainshaft) speed sensor and (b) the intermediate shaft speed sensor.
Air Conditioning Clutch Switch - When battery power is supplied to the A/C compressor clutch solenoid, a corresponding signal is sent to the PCM, which interprets it as an increase in engine load and adjusts idle speed accordingly.