Engine - Coolant Temperature Sensor/Switch: Description and Operation

PURPOSE
Responds to temperature changes of engine coolant and sends a coresponding signal to the engine control module (ECM).

OPERATION
The engine coolant temperature sensor affects the operation of the following ECM output systems and/or devices:
- Fuel injection quantity
- Idle air control valve (idle speed)
- Purge solenoid valve (purge control)
- A/C relay (A/C cut-off control system)
- Ignition control module (ignition timing control)
- EGR solenoid valves (EGR operation)
- Pressure regulator control solenoid valves (fuel pressure)
- Transaxle control module (TCM)
- Coolant fan relay (coolant fan control)

REMARKS
Diagnostic trouble code 09 will be stored in engine control module (ECM) memory, if a failure occurs in the engine coolant temperature sensor or its circuit.