Engine Coolant Temperature (ECT) Sensor High
The engine coolant temperature sensor is reading a voltage that indicates the temperature is too high.
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 coolant temperature sensor is sending a signal that says the engine is overheating, but it might just be a faulty sensor.
What the computer is actually seeing
The Engine Control Module (ECM) detects a coolant temperature reading over a threshold (usually around 225°F or 107°C) when the engine is at normal operating temperature.
What a healthy reading looks like
Normal expected range from the ECT sensor is 194°F to 221°F (90°C to 105°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 in the reservoir and radiator. Add if low. Decision: If low, refill and monitor. If okay, proceed.
- 22. Inspect wiring and connector for damage or corrosion. Repair any issues found. Decision: If fixes are made, retest. If wiring is good, proceed.
- 33. Use a scan tool to verify the ECT sensor reading. Compare to actual coolant temperature using a thermometer. Decision: If readings match within 10°F, the sensor may be fine. If not, proceed.
- 44. Replace the ECT sensor. Decision: If after replacement the code returns, further diagnosis is needed for wiring or ECM issues.
Common causes
- Faulty coolant temperature sensor
- Shorted wiring or connector
- Low coolant level
- Poor ground connection
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive the vehicle with this code?
Driving with an overtemperature condition can cause engine damage. It's better to address this issue immediately.
Will this come back after clearing the code?
If the underlying problem isn't fixed, it likely will come back after clearing.
Why does this code pair with others like SPN 1377?
These codes often relate to the same issues regarding coolant temperature and indicate further problems with the engine's cooling system.
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 →