Engine Coolant Temperature Sensor
Indicates high engine coolant temperature.
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 coolant temperature sensor measures how hot the engine coolant is. If this number gets too high, it’s a sign that the engine could be overheating, which can cause serious damage if not addressed quickly.
What the computer is actually seeing
The engine control module (ECM) expects the coolant temperature to stay between 185°F to 220°F (85°C to 105°C) under normal operating conditions. If it detects a reading above 245°F (118°C), it sets SPN 117.
What a healthy reading looks like
Coolant temperature readings should be between 185°F and 220°F (85°C to 105°C) during normal operation; above 245°F (118°C) triggers a fault code.
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. Is it low? If yes, refill and recheck. If coolant is full, proceed to step 2.
- 22. Inspect wiring and connectors to the coolant temperature sensor for any signs of damage or corrosion. Is there any visible damage? If yes, repair the wiring. If no, proceed to step 3.
- 33. Using a scan tool, check the coolant temperature reading. What value are you seeing? If it reads above 245°F (118°C), proceed to step 4. If it reads normally, check for overheating issues in the engine system.
- 44. Start the engine and monitor the temperature of the engine from a reliable gauge. Is the engine cooling fan operational? If not, repair or replace the cooling fan. If the fan is working, go to step 5.
- 55. Replace the coolant temperature sensor if all previous steps are clear and the issue persists.
Common causes
- Faulty coolant temperature sensor
- Wiring issue (short or open)
- Overheating engine due to low coolant
- Failed thermostat
- Blocked coolant passages
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you can drive it, but overheating can cause engine damage, so fix it soon.
Will this code come back after repair?
If the cause, like a faulty sensor or wiring issue, is fixed properly, it should not reappear.
Why does this issue pair with overheating symptoms?
Overheating will cause the coolant temperature to be high, triggering this fault code as a protective measure.
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 →