Engine Coolant Temperature Sensor Circuit
The engine coolant temperature sensor is reporting a fault.
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 is reading too high or too low, which can mess with the engine management and cause performance issues.
What the computer is actually seeing
The ECM is detecting an unexpected resistance value from the coolant temperature sensor, indicating either an open circuit or a short to ground or power.
What a healthy reading looks like
Expected resistance should be around 2.5k ohms at 70°F (21°C) and decrease as temperature rises; over 200°F (93°C) resistance should be around 100-200 ohms.
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. Inspect the wiring and connectors to the engine coolant temperature sensor for damage, corrosion, or loose connections.
- 22. Check the coolant level in the reservoir; it should be within the proper range—below the low mark suggests a leak or low fill.
- 33. Use a multimeter to test resistance at the coolant temperature sensor connector; it should match expected values based on current temperature.
- 44. Start the engine and use a scan tool to monitor the coolant temperature reading; is it within a reasonable range when the engine is running?
- 55. If the sensor reading is erratic or out of range, replace the coolant temperature sensor.
- 66. Recheck wiring and connectors after replacement to ensure the issue is resolved.
Common causes
- Faulty engine coolant temperature sensor
- Damaged wiring or connectors
- coolant level low or contaminated
- ECM calibration issue
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive with this code active?
It's not recommended to drive as it can cause overheating or poor engine performance.
Will this code clear itself?
Not likely; it will need to be reset after the problem is fixed.
Why does this code sometimes appear with SPN 3361?
Both codes deal with coolant temperature issues that could be related to each other, often indicating a sensor or circuit issue.
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 →