Coolant temperature sensor performance
This code indicates an issue with the coolant temperature sensor's performance or range.
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 measures how hot the engine's coolant is. If it's not reading correctly, the computer can't tell if the engine is overheating or if it's running too cold.
What the computer is actually seeing
The engine control module (ECM) expects the coolant temperature to be within a specific range while the engine is running. If the readings are out of range or inconsistent, the ECM sets the SPN 2446 code.
What a healthy reading looks like
Expected coolant temperature readings typically range from 180°F to 220°F (82°C to 104°C) for most engines. A proper signal is usually around 0.5V to 4.5V depending on temperature.
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.
- 1Check the coolant level; it should be at the correct level in the reservoir and radiator.
- 2Inspect the wiring and connectors of the coolant temperature sensor for damage, corrosion, or loose connections.
- 3Using a multimeter, test the sensor's resistance and voltage output against the expected values during engine warm-up.
- 4If the coolant temperature sensor shows no issues, check for ECM faults or other related codes.
Common causes
- Faulty coolant temperature sensor
- Wiring issues or damaged connectors
- Low coolant level
- Faulty engine control module (ECM)
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s moderate; you can drive but should fix it soon to avoid overheating issues.
Will this code come back after I clear it?
If the problem isn't fixed, yes, it will return.
Why does this code pair with other SPN codes?
Other codes may indicate related issues like coolant flow or sensor signal integrity.
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