Engine Coolant Temperature Sensor Low
The engine coolant temperature sensor is reporting a low voltage condition.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine computer is getting a signal from the coolant temperature sensor that's lower than expected, indicating the engine might be running cooler than it should.
What the computer is actually seeing
The engine control module (ECM) sees a coolant temperature sensor voltage output of less than 0.1 volts when it should be around 0.5 to 4.5 volts, indicating abnormal temperature readings.
What a healthy reading looks like
Coolant temperature sensor should output between 0.5 to 4.5 volts based on temperature scale (typically 176°F to 212°F for 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 and there are no leaks.
- 22. Inspect the wiring and connectors to the coolant temperature sensor for damage or corrosion.
- 33. Using a multimeter, check the voltage output of the coolant temperature sensor; it should range from 0.5 to 4.5 volts under normal operation.
- 4 - If voltage is below 0.1 volts, proceed to step 4.
- 5 - If voltage is within range, suspect ECM malfunction.
- 64. Disconnect the sensor and check resistance; it should vary with temperature (refer to specific sensor resistance chart).
- 7 - If resistance is incorrect, replace the coolant temperature sensor.
- 8 - If resistance is correct, check for short circuits in the wiring.
Common causes
- Wiring issues or connector faults to the coolant temperature sensor
- Faulty coolant temperature sensor
- Low coolant level affecting sensor readings
- Short circuit to ground in the sensor circuit
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable but expect potential overheating issues as the engine may not know its coolant temperature accurately.
Will this code come back after clearing?
If the issue is not resolved, yes, it may come back when the conditions are recreated.
Why does this problem pair with other codes?
Engine temperature affects many systems; if the coolant temperature report is inaccurate, it can lead to erratic behavior elsewhere.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →