Engine Coolant Temperature Sensor 1 - Below Normal Operating Range
The engine coolant temperature sensor is reporting a temperature below the normal range.
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What it means (plain English)
The computer checks the coolant temperature to make sure the engine is running at a proper heat level. If the coolant is too cold, it can signal that the engine is not warming up properly, which can lead to inefficient operation.
What the computer is actually seeing
The engine control module (ECM) sees a voltage reading from the coolant temperature sensor that is lower than the expected range, usually less than 150°F (65°C) when the engine should be warm.
What a healthy reading looks like
Normal coolant temperature should be between 176°F (80°C) and 221°F (105°C) when the engine is operating properly.
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; top off if low. If level is fine, go to step 2.
- 22. Inspect wiring and connector at the coolant temperature sensor for damage or corrosion. Repair any issues found. If wiring is good, go to step 3.
- 33. Use a scan tool to monitor the coolant temperature reading. Compare this reading to the engine temperature. If it's below expected values, replace the coolant temperature sensor. If the sensor is working correctly, go to step 4.
- 44. Check the thermostat operation: with the engine cold, the thermostat should be closed. As the engine warms, feel the upper radiator hose; if it doesn't get hot in a timely manner, the thermostat might be stuck closed.
Common causes
- Failed coolant temperature sensor
- Open or short in the wiring to the sensor
- Low coolant level
- Faulty thermostat
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally safe to drive, but performance may be reduced, and abnormal wear can occur if not addressed.
Will the code come back after clearing?
It may come back if the underlying issue isn't fixed.
Why does this code often pair with SPN 0710?
Both codes pertain to coolant temperature, with SPN 0710 indicating a high temperature condition, while SPN 0711 is for low temperatures.
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