Engine Coolant Temperature Sensor 1
Indicates a problem with the engine coolant temperature sensor.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine's computer is not getting a correct reading from the coolant temperature sensor, which affects how the engine runs.
What the computer is actually seeing
The engine control unit gets a variable voltage signal from the coolant temperature sensor. A normal signal ranges approximately from 0.5V at -40°C to 4.5V at 125°C. If it's out of expected range, it triggers the code.
What a healthy reading looks like
Expected voltage is between 0.5V to 4.5V corresponding to temperature ranges.
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 wiring and connectors for damage or corrosion. Repair if needed. Proceed to step 2 if all looks good.
- 22. Check the coolant level in the reservoir. Refill to the correct level if low. If level was fine, move to step 3.
- 33. Using a multimeter, measure the voltage at the coolant temperature sensor harness with the key on and engine off. Expect 0.5V to 4.5V. If out of range, replace sensor. If in range, proceed to next step.
- 44. Start the engine and monitor the voltage signal while the engine warms up. It should change in correlation with temperature. If it sticks at a certain voltage, the sensor is faulty.
Common causes
- Wiring issues or corrosion in connectors
- Faulty coolant temperature sensor
- Coolant level too low affecting sensor reading
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; you'll want to fix it soon to avoid drivability issues.
Will this code come back after erasing it?
If the underlying issue isn't fixed, yes, the code will likely return.
Why does this issue sometimes pair with other fault codes?
A malfunctioning temperature sensor can affect various engine parameters, leading to multiple codes being set.
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