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When the engine is cold, the PCM will operate in Open Loop cycle. It will demand slightly richer air-fuel mixtures The PCM uses inputs from the ECT sensor for the following calculations: • for engine coolant temperature gauge operation through CCD or PCI (J1850) communications • Injector pulse-width • Spark-advance curves • ASD relay shut-down times • Idle Air Control (IAC) motor key-on steps • Pulse-width prime-shot during cranking • O2 sensor closed loop times • Purge solenoid on/off times • EGR solenoid on/off times (if equipped) • Leak Detection Pump operation (if equipped) • Radiator fan relay on/off times (if equipped) • Target idle speed REMOVAL 3.7L ENGINE The Engine Coolant Temperature (ECT) sensor (3) on WARNING: HOT, PRESSURIZED COOLANT CAN 1. Partially drain the cooling system. (Refer to 7 - COOLING - STANDARD PROCEDURE). 2. Disconnect the electrical connector from the sensor (3). 3. Remove the sensor from the intake manifold. 7 - 28 ENGINE ND |