Diagnostic Procedures

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.






CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Specification data are reference values.






ON BOARD DIAGNOSIS LOGIC






FAIL-SAFE MODE
When the ECM enters the fail-safe mode, the MIL illuminates.


DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE

NOTE: If "DIAGNOSTIC TROUBLE CODE CONFIRMATION PROCEDURE" has been previously conducted, always turn ignition switch "OFF" and wait at least 5 seconds before conducting the next test.






With CONSULT
(1) Turn ignition switch "ON".
(2) Select "DATA MONITOR" mode with CONSULT.
(3) Wait at least 5 seconds.






Electrical Diagrams





Circuit Connectors







DIAGNOSTIC PROCEDURE


COMPONENT INSPECTION
Engine coolant temperature sensor












Check resistance as shown in the figure.

If NG, replace engine coolant temperature sensor.