DTC 14

Fig. 042 Code 14 Coolant Sensor Circuit:

Fig. 043 - Wiring Diagram for Code 14 Coolant Sensor Circuit. VIN P:

CODE 14, COOLANT SENSOR (SIGNAL VOLTAGE LOW)

The Coolant Temperature Sensor uses a thermistor to control the signal voltage to the ECM. The ECM applies a voltage on CKT 410 to the sensor. When the engine is cold the sensor (thermistor) resistance is high, therefore the ECM will see a high signal voltage.
As the engine warms, the sensor resistance becomes less, and the voltage drops. At normal engine operating temperature the voltage will measure about 1 to 1.5 volts at the ECM terminal C10.
Code 14 will set if signal voltage indicates a coolant temperature above 135°C for more than two seconds.
Coolant temperature is one of the inputs used to control:
a. Fuel delivery.
b. Spark Timing (EST)
c. Idle (IAC)
d. Convertor Clutch (TCC)
e. Puslair
f. EGR
1. If voltage is above 4 volts, the ECM and wiring are OK.
2. If checking resistance at the coolant sensor is difficult because of sensor location, disconnect the ECM connectors and check resistance between harness connector terminals C10 and A11.