Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSMAZDA1999626 ES, 2.5 D, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 403 (ENGINE CONTROL SYSTEM)ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTIONRESISTANCE INSPECTION
1999 Mazda 626 ES, 2.5 D, Standard
Resistance Inspection
1999 Mazda 626 ES, 2.5 D, StandardSECTION 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 .
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)
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.