Engine Coolant Temperature Sensor 1 Out of Range
The engine coolant temperature sensor signal is out of the expected range.
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What it means (plain English)
The engine coolant temperature sensor tells the ECM how hot the engine is running. If it reads too high or too low, it can mess with your engine's performance and emissions.
What the computer is actually seeing
The control module expects a voltage signal from the coolant temperature sensor that typically falls within 0.5 to 4.5 volts. A reading outside of this range indicates a problem.
What a healthy reading looks like
0.5 to 4.5 volts from the coolant temperature sensor, corresponding to -40°C (-40°F) to 140°C (284°F).
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.
- 1Check the coolant level; ensure it's at the correct level before proceeding.
- 2Inspect the wiring and connectors of the coolant temperature sensor for damage, corrosion, or loose connections.
- 3Measure the voltage at the coolant temperature sensor; it should be within 0.5 to 4.5 volts. If not, replace the sensor.
- 4Measure the engine coolant temperature with a scan tool or multimeter to verify it's within expected range. If the reading doesn't match, further inspection is needed on the sensor or the ECM.
Common causes
- Bad coolant temperature sensor
- Wiring issues or poor connections
- Coolant leaks affecting temperature
- Faulty ECM
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with SPN 2287 active?
It's generally drivable but monitor for overheating. Address it soon to avoid potential engine damage.
Will this code come back after repairs?
If the root cause is fixed properly, it shouldn't return. Always check your repairs.
Why do I see this code with a check engine light?
The check engine light indicates there's a problem detected by the ECM, and this code is a specific issue related to temperature readings.
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