ECT Sensor Circuit Troubleshooting

1.Check the malfunction indicator lamp (MIL).

Does the malfunction indicator lamp come on?

YES - Refer to the fuel and emissions section.n

NO - Go to 2.

2.Turn the ignition switch OFF.

3.Disconnect the ECM sensor 2P connector.

4.Disconnect climate control unit connector A (12P).

5.Turn the ignition switch ON (II).

Measure the voltage between the No.12 terminal of climate control unit connector A (12P) and body ground.


Is there about 5 V?

YES - Check for loose wires or poor connections at climate control unit connector A (12P) and at the ECT sensor 2P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original  climate control unit.n

NO - Repir open in the wire between the climate control unit and the ECT sensor.n