Coolant Temperature Sensor/Switch

Coolant temperature sensor/switch is installed in the intake manifold coolant and monitors engine coolant temperature. Coolant temperature information is transmitted to the ECU through input voltage generated by sensor/switch. ECU uses this information to adjust injector pulse width, compensate fuel condensation in the manifold, control warm-up idle speed, increase advance when coolant is cold, and energize EGR valve solenoid to prevent vacuum to EGR valve (cold engine).