Engine Cooling Temperature Sensor 1
The engine cooling temperature sensor is reporting a malfunction or out-of-range signal.
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 weird readings from the cooling temperature sensor, which is supposed to track the coolant temperature to prevent overheating.
What the computer is actually seeing
The engine control module (ECM) expects a voltage signal between 0.5V to 4.5V from the coolant temperature sensor, with specific values tied to temperature ranges. Any signal outside this range indicates a fault.
What a healthy reading looks like
Expected voltage signal from the coolant temperature sensor ranges from 0.5V at -40°C to 4.5V at 125°C; best results at around 1.0V for 0°C.
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—make sure it's at the proper level before proceeding. If low, fill it and check for leaks.
- 22. Inspect the wiring and connector for the coolant temperature sensor for any signs of damage or corrosion. Repair any issues found.
- 33. Using a multimeter, check the voltage output of the coolant temperature sensor. It should vary between 0.5V and 4.5V under different temperature conditions. If readings are outside this range, replace the sensor.
- 44. Test the ECM for any internal faults if the sensor and wiring are in good condition and the output is abnormal.
Common causes
- Open or short circuit in the sensor wiring
- Corrosion or poor connection at the sensor or ECM
- Faulty coolant temperature sensor
- Low coolant level
- Engine overheating conditions
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; you can drive but keep an eye on engine temperature to avoid overheating.
Will this code come back after clearing?
If the underlying issue isn't fixed, yes, it will likely return.
What else might be affected by this issue?
Engine performance can be impacted, especially if the ECM alters fuel delivery to prevent overheating.
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 →