Engine Coolant Temperature Sensor 1 Out of Range
The engine coolant temperature sensor has reported a value outside of its normal range.
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What it means (plain English)
The engine management computer is getting readings from the coolant temperature sensor that aren't making sense, usually too high or too low, which can affect engine performance.
What the computer is actually seeing
The coolant temperature sensor typically reports values between 0°C to 120°C (32°F to 248°F). If the reading is below -40°C (-40°F) or above 140°C (284°F), it triggers this fault code.
What a healthy reading looks like
Expected coolant temperature readings under normal operation should be between 75°C to 100°C (167°F to 212°F) once the engine is warm.
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 connector for the coolant temperature sensor for damage or corrosion. Fix any issues found. Decision: Is the wiring solid? If YES, proceed. If NO, repair wiring.
- 22. Check the coolant level in the radiator and reservoir. Ensure it is within the correct range. Decision: Is coolant level adequate? If YES, proceed. If NO, top off coolant and retest.
- 33. Use a scan tool to monitor the actual coolant temperature reading while the engine is running. Compare this reading to the expected values. Decision: Does the reading fall within 75°C to 100°C (167°F to 212°F)? If YES, code may be intermittent or false. If NO, proceed.
- 44. Replace the coolant temperature sensor and clear the fault codes. Decision: Did the fault code return after replacement? If YES, consider further diagnosis of the ECM or related wiring. If NO, repair complete.
Common causes
- Faulty coolant temperature sensor
- Wiring issues (shorts or opens)
- Corroded connectors
- Low coolant levels
- Faulty engine control module (ECM)
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally safe to drive short distances, but the engine may run poorly, affecting drivability and emissions.
Will this problem come back after I fix it?
If the wiring and sensor are addressed properly, it should not return, but always monitor for other related issues.
Why does this code pair with SPN 3055?
SPN 3055 is often related to other temperature readings, so if the coolant sensor is faulty, it can trigger multiple errors.
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