DTC 15

Fig. 064 Chart - Code 15 Coolant Sensor Circuit:

Fig. 066 - Wiring Diagram for Code 15 Coolant Sensor Circuit. VIN P:

CODE 15

COOLANT SENSOR

(SIGNAL VOLTAGE HIGH)

2.0L "J" SERIES

FUEL INJECTION (TBI)

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 on CKT 410.
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 15 will set if:
a. Signal voltage indicates a coolant temperature less than -35°C (-24°F) for 10 seconds.
b. Time since engine start is more than 1 minute.
Coolant temperature is one of the inputs used to control:
- Fuel delivery.
- Spark Timing (EST)
- Idle (IAC)
- Convertor Clutch (TCC)
1. If voltage is above 4 volts, the ECM and wiring are OK.