High-Resolution Engine Coolant Temperature Sensor
Coolant temperature sensor reading is out of expected range.
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What it means (plain English)
The temperature sensor for the engine coolant isn’t giving the right temperature reading, which can affect engine operation.
What the computer is actually seeing
The engine control unit (ECU) is monitoring the coolant temperature sensor and expects a voltage between 0.3V (cold) to 4.9V (hot). If it reads below 0.1V or above 4.9V, the system flags a fault.
What a healthy reading looks like
Coolant temperature should ideally range from 175°F to 220°F (80°C to 105°C) under normal operating conditions.
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 the coolant level; ensure it's at the proper level. Decision: If low, top it off and retest the system. If okay, proceed.
- 22. Inspect the sensor wiring and connector for damage or corrosion. Decision: If any issues found, repair or replace as necessary. If not, proceed.
- 33. Use a multimeter to check the voltage at the coolant temperature sensor connector (should be between 0.3V - 4.9V). Decision: If out of range, replace the sensor. If within range, proceed.
- 44. Start the engine and monitor the live data for coolant temperature with a scan tool. Decision: If data is erratic or doesn’t correlate with expected operational temps, replace the sensor.
Common causes
- Faulty coolant temperature sensor
- Wiring issues (frayed, shorted, or open circuits)
- Poor connection at the sensor or ECU
- Cooling system air pockets
- Incorrect coolant level
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally safe to drive for a short distance, but monitor the temperature gauge closely to avoid overheating.
Will this code come back after resetting?
If the underlying issue isn't resolved, yes, it will likely return.
Why does this code appear with other codes?
This often happens if there are multiple sensor faults or wiring issues affecting communication.
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