Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection

TESTING PROCEDURE:

NOTE: Check that coolant temperature and knock sensor connectors at engine block are not interchanged.
While trouble shooting, always check the wiring, fuses and connectors for good condition and routing. Also check ground locations for good connection. Use the wiring diagrams found in SCHEMATIC DIAGRAMS to supplement your testing efforts.

Color Code Legend:

Checking ECU Ground Connections:

1. Turn ignition OFF.
2. Access fuel injection ECU by removing the passenger side kick panel and glove compartment.
3. Check fuel injection ECU ground connections. They should make good contact and fit tight.

Removing ECU Connector:

4. Remove the ECU connector by pressing up the latch and folding out the wire cluster.

Removing Protective Cover:

5. Remove connector protective sleeve.
CAUTION: ^ Never check connections from the front. Connectors can get damaged and worsen the problem.
^ Check connections through the holes in the connector.
^ Connection pin numbers are printed on the connector side.

Checking Coolant Temperature Sensor:

6. Check temperature sensor by connecting an ohmmeter between ground and ECU connector pin 2.

Temperature Chart:

7. Resistance depending on coolant temperature should be (also see chart):

14°F (-10°C) 8,260 - 10,560 ohms
68°F (+20°C) 2,280 - 2,720 ohms
176°F (+80°C) 290 - 364 ohms

8. If a fault occurs, measure at coolant temperature sensor to see if the sensor or the wiring is the problem.
a. If reading is the same at the sensor, replace sensor and retest.
b. If reading at sensor is correct, check wiring and ground connection.

Assemble Connector:

9. Disconnect the test equipment. Reconnect the ECU and all other connectors, install the kick panel and glove compartment.