Engine Cooling Temperature Sensor Out of Range
The cooling temperature sensor is reporting a temperature that is out of the expected range.
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What it means (plain English)
The engine cooling temperature sensor is either reading too high or too low compared to normal values, which can affect the engine's cooling performance and efficiency.
What the computer is actually seeing
The engine control module (ECM) is receiving temperature data from the coolant temperature sensor that falls outside of the calibrated range, usually below -40°C (-40°F) or above 150°C (302°F).
What a healthy reading looks like
Normal engine operating temperature should be between 85°C (185°F) and 105°C (221°F). Sensor voltage should typically be between 0.5V and 4.5V according to the temperature reading.
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 coolant level; ensure it's at proper level.
- 22. Inspect wiring and connectors of the coolant temperature sensor for damage or corrosion. Repair as necessary.
- 33. Using a multimeter, check the voltage at the coolant temperature sensor while the engine is running. It should be between 0.5V and 4.5V. If it's out of range, replace the sensor.
- 44. Verify the engine operating temperature with a calibrated thermometer or scan tool. If the engine is outside the normal range (85°C to 105°C), inspect the thermostat and engine cooling system for issues.
- 55. If the sensor and cooling system are functioning correctly, consider reprogramming or updating the ECM if applicable.
Common causes
- Faulty coolant temperature sensor
- Wiring issues (shorts, opens, corrosion)
- Coolant leaks or low coolant level
- Failed engine thermostat
- ECM software issues
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with SPN 2952 active?
It's moderate severity; you can drive but fix it soon to avoid overheating risks.
Will this code come back after I clear it?
If the underlying issue isn't fixed, yes, the code will likely return.
Why does SPN 2952 pair with other codes like SPN 2159?
They can both relate to cooling system performance issues and may trigger together.
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