Engine Cooling Temperature Sensor 1 - Out of Range
The engine cooling temperature sensor is reporting a value outside the expected range.
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What it means (plain English)
The engine cooling temperature sensor measures the coolant temperature; if it's way too high or low, it could mean the sensor is faulty or the engine is actually overheating.
What the computer is actually seeing
The computer sees communication from the cooling temperature sensor reporting values that exceed the preset thresholds, typically below -40°F (-40°C) or above 248°F (120°C).
What a healthy reading looks like
Engine coolant temperature should generally range from 160°F to 210°F (70°C to 99°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 wiring and connector at the engine coolant temperature sensor for damage or corrosion. Fix as necessary.
- 22. Verify the coolant level in the system; ensure it’s topped off to the correct level. Add coolant if necessary and recheck the code.
- 33. Using a scan tool, read the engine coolant temperature sensor value. If it reads below -40°F (-40°C) or above 248°F (120°C), proceed.
- 44. Measure the resistance of the engine coolant temperature sensor with a multimeter; expected values should be around 2.5k ohms at 77°F (25°C). If out of range, replace the sensor.
- 55. Check the engine thermostat; ensure it opens at the correct temperature. If stuck closed, replace the thermostat and flush the cooling system.
Common causes
- Faulty engine coolant temperature sensor
- Wiring issues between the sensor and ECM
- Faulty engine thermostat
- Coolant leaks or insufficient coolant
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to fix it soon; if the engine is overheating, it could lead to serious damage.
Will this code come back after resetting?
If the underlying issue isn't resolved, it will likely return.
Why do I see this code along with SPN 4526?
Both codes are related to cooling system functions, indicating multiple issues with the temperature sensing or cooling performance.
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