Engine - Coolant Temperature Sensor/Switch: Testing and Inspection

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.




DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE
WITH CONSULT
1. Turn ignition switch "ON".
2. Select "DATA MONITOR" mode with CONSULT
3. Wait at least 5 seconds.

OR

WITH GST
1. Turn ignition switch "ON" and wait at least 5 seconds.
2. Select "MODE 3" with GST.

OR

WITH NO TOOLS
1. Turn ignition switch "ON" and wait at least 5 seconds.
2. Turn ignition switch "OFF", wait at least 5 seconds and then turn "ON".
3. Perform diagnostic test mode II (Self-diagnostic results) with ECM.




WIRING DIAGRAM




DIAGNOSTIC PROCEDURE

COMPONENT INSPECTION




Check resistance as shown in the figure.




If NG, replace engine coolant temperature sensor.