Engine Temperature Sensor 1 - Voltage Above Normal
The engine temperature sensor is reading a voltage that's higher than normal limits.
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What it means (plain English)
Inside the engine control unit, an engine temperature sensor monitors the coolant temperature. If it detects a voltage higher than 4.5 volts, it triggers this code, indicating a possible short circuit or sensor malfunction.
What the computer is actually seeing
The ECM expects the voltage level from the engine temperature sensor to stay between 0.5V and 4.5V. A reading above 4.5V means something's wrong, potentially a short circuit or a defective sensor.
What a healthy reading looks like
Normal voltage from the engine temperature sensor should be between 0.5V and 4.5V. Anything over 4.5V is considered above normal.
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. Check the wiring and connectors to the engine temperature sensor for damage or corrosion. If they're good, move to step 2.
- 22. Measure the voltage at the engine temperature sensor connector with the engine running. If it's above 4.5 volts, proceed to step 3. If it's normal, replace the sensor.
- 33. Disconnect the sensor and check the resistance across its terminals. It should be within spec (usually around 500-1500 ohms at room temperature). If the sensor is out of spec, replace it.
Common causes
- Faulty engine temperature sensor
- Wiring harness issues
- Short circuit in the sensor circuit
- ECM software issue
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity, so you can drive but should fix it soon to avoid overheating issues.
Will this code come back after resetting?
If the underlying issue isn't fixed, the code is likely to return after a short time.
Why does this code show with other engine temperature codes?
Multiple temperature sensors can trip codes if there's a shared wiring issue or if the ECM is reading confusing signals.
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