Transmission Fluid Temperature Sensor 1
Indicates a problem with the transmission fluid temperature sensor.
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 transmission fluid temperature sensor measures the temperature of the transmission fluid to prevent overheating and ensure optimal shifting. If it reads too high or too low, it can affect vehicle performance.
What the computer is actually seeing
The engine control unit (ECU) monitors the voltage from the transmission fluid temperature sensor, which should be between 0.5V (cold) to 4.5V (hot). An out-of-range voltage indicates a fault.
What a healthy reading looks like
Expected voltage range is between 0.5V and 4.5V typically, with 100°C (212°F) corresponding to approximately 2.5V.
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 transmission fluid level; ensure it's within specs.
- 22. Inspect wiring and connectors to the transmission fluid temperature sensor for damage or corrosion; repair as needed.
- 33. Use a scan tool to read live data from the transmission fluid temperature sensor; verify if voltages are within 0.5V - 4.5V.
- 44. If the voltage is out of range, replace the transmission fluid temperature sensor. If it’s within range, check for ECM updates or further diagnostics.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues or damaged connectors
- Low transmission fluid level
- Faulty ECM (engine control module)
- Contaminated fluid affecting sensor operation
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Yes, but you may experience shifting issues and potential overheating of the transmission if left unaddressed.
Will this code come back after clearing?
It may return if the underlying issue isn't fixed, like a bad sensor or wiring issue.
Why does this code sometimes pair with other transmission codes?
Other transmission codes can trigger alongside this fault due to interdependencies in the transmission control system.
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 →