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.
2007 Mazda 6 L4-2.3LFACTORY OEM SERVICE PROCEDURE
Engine Temperature Sensor: Testing and Inspection
ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION[L3]
NOTE: Perform the following inspection only when directed.
ECT Sensor Resistance Inspection
1. Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS[L3, AJ].)
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 normal, but PID value is out of specification, perform the "Circuit Open/Short Inspection".
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Inspect the following wiring harnesses for open or short circuit. (Continuity inspection)
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- ECT sensor terminal A and PCM terminal 2AH
- ECT sensor terminal B and PCM terminal 2AY
Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- ECT sensor terminal A and power supply
- ECT sensor terminal A and body GND
- ECT sensor terminal B and power supply
NOTE: Perform the following inspection only when directed.
ECT Sensor Resistance Inspection
1. Drain the engine coolant. (See COOLING SYSTEM SERVICE WARNINGS[L3, AJ].)
2. Remove the ECT sensor (located above the starter).
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 normal, but PID value is out of specification, perform the "Circuit Open/Short Inspection".
Circuit Open/Short Inspection
1. Disconnect the PCM connector.
2. Inspect the following wiring harnesses for open or short circuit. (Continuity inspection)
Open circuit
- If there is no continuity, there is an open circuit. Repair or replace the wiring harness.
- ECT sensor terminal A and PCM terminal 2AH
- ECT sensor terminal B and PCM terminal 2AY
Short circuit
- If there is continuity, there is a short circuit. Repair or replace the wiring harness.
- ECT sensor terminal A and power supply
- ECT sensor terminal A and body GND
- ECT sensor terminal B and power supply
Factory Service Tools
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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.
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