With PFI

Fig. 024 - WIRING DIAGRAM for Code 14 Coolant Sensor Circuit (Signal Voltage Low). VIN J:

CODE 14,

COOLANT SENSOR

(SIGNAL VOLTAGE LOW)

1.8L TURBO "J" SERIES

FUEL INJECTION (PORT)

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 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 (275°F) for more than two seconds.

Possible causes of a Code 14 are:
a. A shorted coolant sensor
b. Faulty wiring or terminls
c. 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)

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

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 terminals C-10 and D-2.