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 sensor that measures the transmission fluid temperature is sending wrong data, which can lead to transmission issues.
What the computer is actually seeing
The engine control module (ECM) monitors the resistance of the transmission fluid temperature sensor. If the resistance is out of the expected range, it triggers the fault code.
What a healthy reading looks like
Transmission fluid temperature should be around 150°F to 230°F (65°C to 110°C) during normal 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; it should be within the recommended range. Correct if low.
- 22. Inspect the wiring and connectors going to the transmission fluid temperature sensor for damage or corrosion. Repair as needed.
- 33. Using a scan tool, monitor the transmission fluid temperature while the engine is running. Compare the readings to expected values (150°F to 230°F).
- 44. If the sensor reading is erratic or out of range, replace the transmission fluid temperature sensor and clear the fault code.
- 55. If the code returns, check the ECM for proper updates or failures.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues or corroded connectors
- Low transmission fluid level
- Faulty ECM or software issue
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable but not recommended; improper transmission fluid temp can cause transmission damage.
Will this code come back after clearing?
It may come back if the root issue isn't addressed or if the sensor is faulty.
Does this code affect the performance of the vehicle?
Yes, incorrect temperature readings can lead to improper shifting, affecting drivability.
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 →