With TBI

Fig. 048 Code 14 Coolant Sensor Circuit:

Fig. 049 - Wiring Diagram for Code 14 Coolant Sensor Circuit. VIN 0, VIN 2, VIN E, VIN R, VIN U:

CODE 14

COOLANT SENSOR CIRCUIT

(SIGNAL VOLTAGE LOW)

FUEL INJECTION (TBI)
The Coolant 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 will measure about 1 to 1.5 volts at the ECM terminal 4.
Code 14 will set if signal voltage indicates a coolant temperature above 135°C (275°F) for more than four seconds.
Coolant temperature is one of the inputs used to control:
a. Fuel delivery.
b. Engine Timing (EST)
c. Idle (IAC)
d. Convertor Clutch (TCC)
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.