Code 0908

The engine coolant temperature sensor is used to detect the engine coolant temperature. The sensor modifies a voltage signal from the ECM. The modified signal returns to the ECM as the engine coolant temperature input. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.




DIAGNOSTIC CHART




OVERALL FUNCTION CHECK
This procedure can be used for checking the overall function of the engine coolant temperature sensor circuit. During this check, a DTC might not be confirmed.

NOTE:
- If both DTC 0103 (P0115) and 0908 (P0125) are displayed, first perform TROUBLE DIAGNOSIS FOR DTC 0103 (P0115).

CONSULT
1) Turn ignition switch "ON".




2) Select "COOLANT TEMP/S" in "DATA MONITOR" mode with CONSULT.
3) Start engine and run it at idle speed.
4) Check that the engine coolant temperature rises to 25°C (77°F) or more within 15 minutes. (Be careful not to overheat engine.)

OR

GST
1) Turn ignition switch "ON".




2) Select "MODE 1" with GST.
3) Start engine and run it at idle speed.
4) Check that the engine coolant temperature rises to 25°C (77°F) or more. within 15 minutes. (Be careful not to overheat engine.)

OR

NO TOOLS
1) Turn switch "ON".




2) Probe voltage meter between ECM terminal (59) and ground.
3) Start engine and run it at idle speed.
4) Check that voltage of engine coolant temperature changes to less than 3.3 (V) within 15 minutes. (Be careful not to overheat engine.)

COMPONENT INSPECTION
Engine coolant temperature sensor




Check resistance as shown in the figure.







If NG, replace engine coolant temperature sensor.




WIRING DIAGRAM