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.
2002 Acura RSX L4-2.0L (VTEC)FACTORY OEM SERVICE PROCEDURE
Coolant Temperature Sensor/Switch (For Computer): Testing and Inspection
ECT Sensor Circuit Troubleshooting
1. Check the malfunction indicator lamp (MIL).
Does the malfunction indicator lamp come on?
YES - Refer to the Fuel and Emissions section.
NO - Go to step 2.
2. Turn the ignition switch OFF.
3. Disconnect the ECT sensor 2P connector.
4. Disconnect the climate control unit 30P connector.
5. Turn the ignition switch ON (II).
6. Measure the voltage between the No.18 terminal of the climate control unit 30P connector and body ground.
Is there about 5 V?
YES - Check for loose wires or poor connections at the climate control unit 30P connector and at the ECT sensor 2P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.
NO - Repair open in the wire between the climate control unit and the ECT sensor.
1. Check the malfunction indicator lamp (MIL).
Does the malfunction indicator lamp come on?
YES - Refer to the Fuel and Emissions section.
NO - Go to step 2.
2. Turn the ignition switch OFF.
3. Disconnect the ECT sensor 2P connector.
4. Disconnect the climate control unit 30P connector.
5. Turn the ignition switch ON (II).
6. Measure the voltage between the No.18 terminal of the climate control unit 30P connector and body ground.
Is there about 5 V?
YES - Check for loose wires or poor connections at the climate control unit 30P connector and at the ECT sensor 2P connector. If the connections are good, substitute a known-good climate control unit, and recheck. If the symptom/indication goes away, replace the original climate control unit.
NO - Repair open in the wire between the climate control unit and the ECT sensor.
Factory Service Tools
Use the Manual With the Right Hardware
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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.