DTC 14

Fig. 022 Chart - Code 14 Coolant Sensor Circuit (Signal Voltage Low):

Fig. 023 - WIRING DIAGRAM for Code 14 Coolant Sensor Circuit (Signal Voltage Low). VIN J:

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.
Possible causes of a Code 14 are:
- A shorted coolant sensor
- Faulty wiring or terminals
- a faulty ECM
Coolant temperature is one of the inputs used to control:
a. Fuel delivery.
b. Engine Timing (EST)
c. Knock Control (ESC)
d. Idle (IAC)
e. Convertor Clutch (TCC)
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 C-D connector and check resistance between harness connector terminals C-10 and D-2.