Resistance Inspection

WARNING: This page is about a different car, the 2005 Mazda MPV. However, it is still accessible from the selected car via links, so may be relevant.

Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS .) (See ENGINE COOLANT REPLACEMENT )
Remove the ECT sensor.
Place the ECT sensor in water with a thermometer, and heat the water gradually.
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 .
Fig 1: Measuring ECT Sensor Resistance
Courtesy of MAZDA MOTORS CORP.

Measure the ECT sensor resistance.

ECT SENSOR RESISTANCE

ECT (°C {°F})	Resistance (kilohm)
20 {68}	35-40
80 {176}	3.6-4.1

ECT sensor characteristics graph (reference)

Fig 2: Identifying ECT Sensor Characteristics Graph

Courtesy of MAZDA MOTORS CORP.