Transmission Fluid Temperature Too High
Transmission fluid temperature exceeds normal operating range.
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What it means (plain English)
The transmission fluid is overheating, which can lead to poor shifting and transmission damage. Normal operating temperatures should be between 160°F and 220°F.
What the computer is actually seeing
The transmission control module (TCM) monitors fluid temperature and sets a fault if it exceeds the threshold, typically 220°F for more than 5 seconds.
What a healthy reading looks like
Normal transmission fluid temperature should be between 160°F (71°C) and 220°F (104°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. Verify transmission fluid level is within range; if low, refill and retest. Decision: If fluid was low, check for leaks before moving on.
- 22. Inspect the transmission fluid temperature sensor and wiring for damage or corrosion. Check voltage and resistance; you should see between 0.5V and 4.5V depending on the temperature. Decision: If damaged or out of spec, replace the sensor.
- 33. Check the transmission cooler for blockages or leaks. Flow should feel steady; any restrictions can cause fluid heating. Decision: If cooler is blocked, repair or replace it.
- 44. Test drive and monitor the transmission fluid temperature with a scan tool; it should normalize under load. Decision: If it overheats again, consider transmission or overload issues.
Common causes
- Low transmission fluid level
- Faulty transmission fluid temperature sensor
- Cooling system issues (radiator leaks, blocked coolers)
- Transmission overload or towing beyond capacity
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive with high transmission temperatures as it can lead to serious transmission damage.
Will this code come back after repair?
If the underlying issue is fixed, the code should not return.
Why does this code appear with other transmission codes?
Overheating can cause or be caused by other transmission faults; they often trigger together.
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