DTC 14

The Coolant Temperature Sensor uses a thermistor to control the signal voltage to the ECM. The ECM applies a voltage on CKT 37 to the sensor. When the engine is cold the sensor (thermistor) resistance is high, therefore the ECM will see high signal voltage on CKT 37. As the engine warms, the sensor resistance becomes less, and the voltage drops.

Code 14 will set if signal voltage indicates a coolant temperature above 145°C (293°F) for more than 120 seconds.

Coolant temperature is one of the inputs used to control:

^ Fuel delivery
^ Canister purge control
^ Electronic spark timing control (EST)
^ AIR control
^ Idle air control (IAC)
^ EGR control
^ Turbocharger wastegate control
^ EGR system-diagnosis

1. If voltage between harness connector terminals M2-10 and M2-18 is above 4 volts, the ECM and wiring are OK.
2. Checking resistance at the coolant sensor may be difficult because Of sensor location. Therefore, in order to measure sensor resistance, disconnect the ECM connectors and check resistance between harness connector terminals M2-10 and M2-18.