DTC 0908

COMPONENT DESCRIPTION
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.




ON BOARD DIAGNOSIS LOGIC

OVERALL FUNCTION CHECK
Use this procedure to check the overall function of the engine coolant temperature sensor circuit. During this check, a 1st trip DTC might not be confirmed.

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

With 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 20°C (68°F) or more within 13 minutes. (Be careful not to overheat engine.)

OR

With 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 20°C (68°F) or more within 13 minutes. (Be careful not to overheat engine.)

OR

NO TOOLS
(1) Turn ignition switch "ON".




(2) Probe voltage meter between ECM terminal 51 and ground.
(3) Start engine and run it at idle speed.
(4) Check that voltage of engine coolant temperature changes to less than 3.5 (V) within 13 minutes. (Be careful not to overheat engine.)




WIRING DIAGRAM




DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION
Engine Coolant Temperature Sensor




Check resistance as shown in the figure.





Temperature °C(°F)/ Resistance K Ohms
20 (68) / 2.1 - 2.9
50 (122) / 0.68 - 1.00
90 (194) / 0.236 - 0.260

If NG, replace engine coolant temperature sensor.