Transmission Fluid Temperature
The transmission control module has detected an abnormal transmission fluid temperature.
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What it means (plain English)
The computer monitors the temperature of the transmission fluid to prevent overheating; if it gets too hot, it registers a fault.
What the computer is actually seeing
The Transmission Control Module (TCM) monitors the temperature signal from the transmission fluid temperature sensor, usually expecting values between 70°F and 250°F (21°C to 121°C) under normal operating conditions.
What a healthy reading looks like
Normal transmission fluid temperature should be between 160°F to 220°F (71°C to 104°C) during operation.
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 transmission fluid level. Top off if low, and ensure it's clean and not burnt. Decision: If fluid is low, fill and retest. If not low, proceed.
- 22. Inspect the wiring and connectors to the transmission fluid temperature sensor for damage or corrosion. Decision: Repair or clean if there are issues. If no issues found, proceed.
- 33. Use a scan tool to check the actual transmission fluid temperature reading and compare it to the expected values. Decision: If the reading is outside normal ranges, consider replacing the temperature sensor.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues or short circuits
- Low transmission fluid level or overheating
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's manageable but fix it soon; prolonged use with overheating can damage transmission.
Will this code come back after repair?
If the underlying issues are resolved, it should not return.
Why do I see this code along with SPN 4205?
SPN 4205 relates to fluid pressure, and both can indicate transmission overheating issues.
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