Engine Coolant Temperature Sensor 1 Voltage Above Normal/Shorted to Voltage
The engine coolant temperature sensor is reading a voltage that’s too high, indicating a problem with the sensor or circuit.
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What it means (plain English)
The sensor that measures how hot your engine coolant is sending a signal that says it's hotter than it really is, or there's a wiring issue. Usually, it sees voltages between 0.5V and 4.5V depending on the temperature, but it shouldn't be above 4.5V.
What the computer is actually seeing
The Engine Control Module expects the coolant temperature sensor to output a voltage between 0.5V (around 0°C) and 4.5V (around 150°C). If it sees anything above 4.5V, it triggers this code.
What a healthy reading looks like
Expect coolant sensor voltage readings between 0.5V to 4.5V under normal conditions; a reading above 4.5V is a fault condition.
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 going to the coolant temperature sensor for damage or corrosion. Repair any issues found.
- 22. Using a multimeter, check the voltage at the coolant temperature sensor connector with the ignition on. It should be between 0.5V and 4.5V. If it’s over 4.5V, move to step 3.
- 33. Disconnect the sensor and test the wiring harness for a short to voltage. If the harness is good, replace the coolant temperature sensor and retest.
Common causes
- Faulty engine coolant temperature sensor
- Shorted wiring to the sensor
- Corroded or poor connections at the sensor
- Open circuit in the sensor wiring
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended as it may affect engine performance and efficiency; fix it soon.
Will this code come back after clearing it?
If the underlying issue isn’t resolved, the code will likely return.
What if it’s paired with other codes?
Look at the related codes, they may indicate simultaneous issues that need to be addressed together.
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