Coolant Temperature Sensor

Coolant temperature sensor is located on left side of engine block, under exhaust manifold. As coolant temperature varies, the coolant temperature sensor's resistance changes which results in a different input voltage to the ECU. Colder coolant temperatures results in longer injector pulse widths (richer air-fuel mixtures), energizing EGR valve solenoid (preventing flow of vacuum to EGR valve), and increased ignition advance.