Mazda 6 Service Manual: Engine coolant temperature (ect) sensor inspection

Note

• Perform the following inspection only when directed.

ECT Sensor Resistance Inspection

1. Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS.)

2. Remove the ECT sensor (located above the starter).

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

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 ECT PID value is out of specification, perform the Circuit Open/Short Inspection.

Specification

Circuit Open/Short Inspection

1. Disconnect the PCM connector. (See PCM REMOVAL/INSTALLATION.)

2. Inspect the following wiring harnesses for open or short. (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 PCM terminal 1M (harness-side)

- ECT sensor terminal B (harness-side) and PCM terminal 2H (harness-side)

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 GND

- ECT sensor terminal B (harness-side) and power supply