Input Devices: Notes

The PCM supplies a buffered (reference) voltage to the various information sensors and switches. The PCM monitors the input components for circuit continuity and out-of-range values. The PCM also provides performance checking. Performance checking refers to the PCM indicating a fault when the signal from an input does not seem reasonable, i.e., a Throttle Position (TP) sensor that indicates a high throttle position at low engine loads or low manifold absolute pressure sensor voltage. The input components may include, but are not limited to the following sensors and switches:

• A/C Compressor Control Module (A/C Relay)
• Camshaft Position (CMP) Sensor
• Clutch Pedal Position (CPP) Switch
• Crankshaft Position (CKP) Sensor
• Electrical Load Idle-Up Signal
• Engine Coolant Temperature (ECT) sensor. In addition to circuit continuity and rationality check, ECT sensor is monitored to ensure its ability to maintain a constant temperature, enabling closed loop fuel control.
• Fuel Level Sensor
• Fuel Tank Pressure (FTP) Sensor
• Heated Oxygen Sensor (HO2S)
• Knock (KS) Sensor
• Mass Airflow (MAF) Sensor
• Power Steering Pressure (PSP) Switch
• Throttle Position (TP) Sensor
• Transaxle Range (TR) Switch
• Vehicle Speed Sensor (VSS)

Vehicles are equipped with different combinations of input devices. Not all devices are used on all models. To determine input device usage on a specific model, see WIRING DIAGRAMS article.