Automatic Transmission Fluid Temperature Sensor - Circuit High
Indicates a high voltage reading from the transmission fluid temperature sensor.
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What it means (plain English)
The transmission fluid temperature sensor measures how hot the transmission fluid is. If it's saying things are too hot when they aren't, it means there's an electrical problem somewhere, like a short or bad connection.
What the computer is actually seeing
The computer expects the sensor to output a voltage between 0.5V and 4.5V based on temperature. If it sees a voltage above 4.5V, it triggers this code.
What a healthy reading looks like
Normal operating voltage should be between 0.5V and 4.5V; 0V indicates an open circuit; above 4.5V indicates a fault.
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. Inspect the wiring and connectors to the transmission fluid temperature sensor for damage or corrosion. Fix any issues found. Decision: Are connections secure and wiring intact? (Yes: continue, No: repair connections/wires)
- 22. Check the fluid level and condition. Ensure the transmission fluid is at the proper level and in good condition. Decision: Is the fluid okay? (Yes: continue, No: top off or change fluid)
- 33. Use a multimeter to test the voltage output from the transmission fluid temperature sensor. Expected voltage should be between 0.5V and 4.5V. Decision: Is the voltage within range? (Yes: sensor is likely okay, No: replace the sensor)
- 44. If the issue persists, check for any shorts to ground in the wiring harness and test continuity between the sensor and the ECM. Decision: Any shorts found? (Yes: fix shorts, No: suspect ECM)
Common causes
- Short in the sensor circuit
- Faulty transmission fluid temperature sensor
- Poor connection or corroded wires
- Faulty engine control module (ECM)
- Incorrect transmission fluid level or type
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Can I drive the vehicle with this code?
It's drivable, but monitor the transmission performance and get it checked soon to avoid overheating.
Will this code clear on its own?
It may clear if the issue is resolved; otherwise, you'll need to clear it manually after repairs.
Why do I see this code with a transmission slipping issue?
A faulty temperature sensor can cause incorrect readings, leading to poor transmission behavior as the computer tries to manage shifting.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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