Engine Temperature Sensor: Testing and Inspection

ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION [AJ]

NOTE: Perform the following test only when directed.

Resistance Inspection

1. Drain the engine coolant.
2. Remove the ECT sensor.




3. Place the ECT sensor in water with a thermometer, and heat the water gradually.




4. Measure the resistance between the ECT sensor terminals using an ohmmeter.
- If not as specified, replace the ECT sensor.
- If the ECT sensor is okay, but PID value or PCM terminal 41 voltage are out of specification, perform the "Circuit Open/Short Inspection".




ECT sensor characteristics graph (reference)

Circuit Open/Short Inspection

1. Disconnect the PCM connector.




2. Connect the SST (104 Pin Breakout Box) with the PCM disconnected.
3. Tighten the connector attaching bolt.

Tightening torque: 3.0-5.4 N.m {30-56 kgf.cm, 27-48 in.lbf}





4. Inspect the following wiring harness for open or short circuit (Continuity check).

Open circuit
- If there is no continuity, the circuit is open. Repair or replace the harness.
- ECT sensor terminal A (harness-side) and 104 pin breakout box terminal 41
- ECT sensor terminal B (harness-side) and 104 pin breakout box terminal 20

Short circuit
- If there is continuity, the circuit is shorted. Repair or replace the harness.
- ECT sensor terminal A (harness-side) and power supply
- ECT sensor terminal A (harness-side) and body ground
- ECT sensor terminal B (harness-side) and power supply