Engine Temperature Sensor Circuit High
The engine temperature sensor is reading too high a voltage.
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What it means (plain English)
The engine control module (ECM) uses the engine temperature sensor to monitor the coolant temperature. If it sees a voltage consistently above the expected range, usually over 4.5 volts, it triggers this fault code, thinking the sensor is malfunctioning or stuck in a high state.
What the computer is actually seeing
The ECM is constantly reading the signal from the engine temperature sensor. If the voltage from the sensor exceeds 4.5 volts, it indicates a potential fault condition, leading to this fault code being logged.
What a healthy reading looks like
Typically, the voltage should be between 0.5 to 4.5 volts corresponding to temperatures from -40°F to around 260°F. Anything higher than that indicates a problem.
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.
- 11. Inspect the wiring and connectors for the engine temperature sensor for frays, shorts, or corrosion. Address any visible issues before further testing.
- 22. Measure the voltage at the sensor connector with the ignition on (engine off). Expect 0.5 to 4.5 volts. If over 4.5 volts, replace the sensor. If below, check for a short in the wiring.
- 33. Disconnect the engine temperature sensor. With the sensor unplugged, check for pin resistance to ground. If the resistance is low or zero, check wiring for shorts to power. If normal, replace the sensor.
Common causes
- Damaged engine temperature sensor
- Wiring issues such as short to power
- Ground faults in the wiring harness
- Faulty ECM
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive with this code?
It's moderate severity; you can drive, but fix it soon to avoid engine performance issues.
Will this code come back after clearing it?
If there’s an underlying issue, like wiring or sensor problems, it will likely come back.
Why does it trigger when the engine is cold?
It triggers because it reads a high voltage indicating a fault; it may not reflect the actual engine temperature.
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