Engine Coolant Temperature Sensor Voltage High
The coolant temperature sensor is reporting a voltage that's too high for normal operation.
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What it means (plain English)
Your engine coolant temperature sensor is sending a signal that indicates the engine is running hotter than it actually is, which can trigger overheating warnings or impact fuel settings.
What the computer is actually seeing
The Engine Control Unit (ECU) sees a voltage input above its normal operating range, typically higher than 4.5 volts, indicating a possible sensor failure or wiring issue.
What a healthy reading looks like
Normal voltage from the coolant temperature sensor should range between 0.5 volts (cold) and 4.5 volts (hot).
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 1Check coolant level; ensure it's at the recommended level.
- 2Inspect wiring harness and connectors to the coolant temperature sensor for damage or corrosion.
- 3Measure the voltage at the coolant temperature sensor connector; it should be 0.5 to 4.5 volts when the engine is at operating temperature.
- 4If voltage is above 4.5 volts, replace the coolant temperature sensor and retest.
- 5If normal voltage is present, check for an open or short circuit in the wiring between the sensor and ECU.
Common causes
- Faulty coolant temperature sensor
- Short in wiring between sensor and ECU
- Corroded connector terminals
- Thermostat stuck closed, causing overheating
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable, but you may face poor fuel economy and potential overheating issues, so address it soon.
Will this code come back after clearing it?
It may return if the underlying issue isn't fixed, such as a bad sensor or wiring problem.
Why does this code sometimes pair with other codes?
Overheating can affect multiple systems and sensors, causing related codes to trigger.
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