DTC 14

Fig. 041 Chart Code 14 Coolant Sensor Circuit (Signal Voltage Low):

Fig. 042 - Wiring Diagram for Code 14 Coolant Sensor Circuit (Signal Voltage Low). VIN 8:

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 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 4.
Coolant temperature is one the inputs used to control:
a. Fuel delivery.
b. Spark Timing (EST)
c. Knock Control (ESC)
d. Idle (IAC)
e. Convertor Clutch (TCC)
f. Canister Purge (CCP)
g. Air Management (A.I.R.)
h. EGR
Code 14 will set if signal voltage indicates a coolant temperature above 275°F (134°C) for 4 seconds.
1. If voltage is above 4 volts, the ECM and wiring are OK.
If checking resistance at the coolant sensor is difficult because of sensor location, disconnect the black ECM connector and check resistance between harness connector terminals 4 and 11.