Engine Coolant Temperature Sensor 2 Circuit High
The PCM detected an unusually high voltage signal from the Engine Coolant Temperature Sensor #2 circuit, indicating the sensor is reading colder than actual coolant temperature or has an electrical fault. This prevents proper fuel mixture and ignition timing adjustments based on actual engine temperature.
What You Might Notice
- Check Engine Light (MIL) illuminated
- Poor fuel economy
- Rough idle or rough running
- Black smoke from exhaust
- Difficulty starting or no-start condition
- Engine misfiring
Most Common Causes
- 1
Loose or corroded ECT sensor connector
Poor electrical connection at the #2 ECT sensor increases resistance, causing the PCM to read an artificially high voltage signal.
- 2
Open or broken ground circuit
A break in the ground wire between the #2 ECT sensor and PCM prevents proper signal return, resulting in a high voltage reading.
- 3
Faulty Engine Coolant Temperature Sensor #2
The sensor itself may be shorted internally or have failed, producing an incorrect high voltage signal to the PCM.
- 4
Shorted or damaged voltage feed wire
A short circuit in the sensor power supply line can cause voltage regulation issues and incorrect sensor readings.
How to Diagnose It
- 1
Check Loose or corroded ECT sensor connector — Poor electrical connection at the #2 ECT sensor increases resistance, causing the PCM to read an artificially high voltage signal.
- 2
Check Open or broken ground circuit — A break in the ground wire between the #2 ECT sensor and PCM prevents proper signal return, resulting in a high voltage reading.
- 3
Check Faulty Engine Coolant Temperature Sensor #2 — The sensor itself may be shorted internally or have failed, producing an incorrect high voltage signal to the PCM.
- 4
Check Shorted or damaged voltage feed wire — A short circuit in the sensor power supply line can cause voltage regulation issues and incorrect sensor readings.
How to Fix It
- 1
Inspect and clean ECT sensor connector
Locate the #2 ECT sensor connector, disconnect it, and inspect for corrosion, moisture, or bent pins. Clean with electrical contact cleaner and reconnect firmly. Clear the code and retest.
- 2
Check and repair ground circuit
Trace the ground wire from the #2 ECT sensor to the PCM. Look for breaks, corrosion, or loose connections. Repair or replace damaged wiring and ensure all connections are tight.
- 3
Replace Engine Coolant Temperature Sensor #2
If connector and wiring are sound, the sensor itself is likely faulty. Drain a small amount of coolant, remove the sensor, and install a new OEM or quality aftermarket replacement. Refill coolant and clear the code.
- 4
Inspect sensor voltage supply wiring
Test the power supply circuit to the sensor using a multimeter. Check for shorts to ground or breaks in the wire. Repair or replace damaged wiring as needed.
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