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HO2S detects oxygen content in exhaust gas and sends this information to PCM. PCM uses input signals from HO2S to vary duration of fuel injection. HO2S heater stabilizes sensor temperature regardless of exhaust gas temperature to allow for more accurate exhaust oxygen content readings. Idle Air Control (IAC) Valve Position Sensor Sensor is incorporated in IAC motor. Sensor senses IAC motor plunger position and sends electrical signal to PCM. Ignition Timing Adjustment Terminal Used for adjusting base ignition timing. When terminal is grounded, PCM timing control function is by-passed, allowing base timing to be adjusted. Intake Air Temperature (IAT) Sensor IAT sensor is incorporated into airflow sensor assembly. This resistor-based sensor measures temperature of incoming air and supplies air density information to PCM. Knock Sensor (KS) KS is located in cylinder block and senses engine vibration during detonation (knock). KS converts vibration into electrical signal. PCM retards ignition timing based on this signal. Manifold Differential Pressure (MDP) Sensor MDP sensor converts negative air pressure in intake manifold plenum into voltage signals sent to PCM. PCM monitors Exhaust Gas Recirculation (EGR) system using these signals. Park/Neutral Position (PNP) Switch (Automatic Transmission) PNP switch senses position of transmission select lever, indicating engine load due to automatic transmission engagement. Based on this signal, PCM commands IAC motor to increase throttle angle, maintaining optimum idle speed. Power Steering Oil Pressure Switch Switch detects increase in power steering oil pressure. When power steering oil pressure increases, switch contacts close, signaling PCM. PCM commands IAC motor, raising idle speed to compensate for drop in engine RPM due to power steering load. Throttle Position (TP) Sensor TP sensor is a variable resistor mounted on throttle body. PCM uses voltage signal from TP sensor to determine throttle plate angle. Vehicle Speed Sensor (VSS) Mounted on transaxle/transmission, VSS sends a pulsing signal to PCM for vehicle speed calculation. PCM uses this calculation for cruise control and fuel cut-off. Volume Airflow (VAF) Sensor Incorporated into airflow sensor assembly, VAF sensor measures intake airflow rate. Intake air flows through tunnel in airflow sensor assembly. VAF sensor sends frequency signal to PCM. PCM uses signal to adjust fuel injection rate. OUTPUT SIGNALS NOTE: Vehicles are equipped with various combinations of computer-controlled components. Not all components listed below are used on every vehicle. To determine component |