Engine - Coolant Temperature Sensor/Switch: Testing and Inspection
ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTIONNOTE: Perform the following test only when directed.
ECT Sensor 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.
Specification:
4. Measure the resistance between the ECT sensor terminals A and B using an ohmmeter.
- If not as specified, replace the ECT sensor.
- If the ECT sensor is okay, but PID value or PCM terminal 38 voltage are out of specification, carry out the "Circuit Open/Short Inspection".
ECT sensor signal characteristic (reference)
Circuit Open/Short Inspection
1. Remove the PCM.
2. Connect the SST (104 Pin Breakout Box) to the PCM as shown.
3. Tighten the connector attaching screw.
Tightening torque
16 - 23 N.m {1.6 - 2.4 kgf.m, 12 - 17 ft.lbf}
4. Inspect for an open or short circuit in the following wiring harnesses by probing the applicable sensor and SST (104 Pin Breakout Box) terminals with ohmmeter leads.
- If there is an open or short circuit, repair or replace wiring harnesses.
- If there is no open or short circuit, replace the ECT sensor.
Open circuit
- ECT signal circuit (ECT sensor connector terminal A and PCM connector terminal 38 through common connector)
- GND circuit (ECT sensor connector terminal B and PCM connector terminal 91)
Short circuit
- ECT signal circuit (ECT sensor connector terminal A and PCM connector terminal 38 to GND)
- GND circuit (ECT sensor connector terminal B and PCM connector terminal 91 to GND)
5. Install the ECT sensor.