Transmission Fluid Temperature Sensor Circuit High
Too high of a voltage from the transmission fluid temperature sensor.
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What it means (plain English)
The transmission fluid temperature sensor is sending a voltage signal that indicates the fluid is too hot, usually above 260°F (127°C). This isn't really about actual fluid temperature but rather the sensor itself over 4.5 volts signaling a problem.
What the computer is actually seeing
The engine control module (ECM) sees a high voltage reading (usually above 4.5 volts) from the transmission fluid temperature sensor, indicating a fault in the sensor or its circuit.
What a healthy reading looks like
The transmission fluid temperature should be below 260°F (127°C). A normal sensor voltage is usually between 0.5 to 4.5 volts depending on the actual temperature.
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 wiring and connector at the transmission fluid temperature sensor for damage or loose connections. Decision Point: Is the wiring in good condition? [Yes - go to step 3; No - repair or replace wiring to fix issue.]
- 22. Measure the voltage at the sensor connector with the ignition on but engine off. Expected value is between 0.5 to 4.5 volts. Decision Point: Is the voltage within range? [Yes - go to step 4; No - replace the temperature sensor.]
- 33. Inspect the transmission fluid level and condition. Is the fluid at the right level and in good shape? [Yes - go to step 5; No - correct fluid level or change fluid first.]
- 44. With the vehicle running, check the transmission fluid temperature while monitoring the scan tool for changes in the sensor reading. Expected readings should correspond to actual hydraulic temperatures. Decision Point: Is the temperature reading reasonable? [Yes - check for other issues; No - replace temperature sensor.]
- 55. Clear the fault codes and take the vehicle for a test drive under various conditions. Check if the code returns. Decision Point: Does the code come back? [Yes - further diagnosis may be required; No - repair complete.]
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issue (short to power)
- Bad connector/pin at the sensor
- Faulty ECM (rare)
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
With this code, it may be safe for short distances, but transmission overheating could lead to severe damage.
Will this code come back after clearing?
If the underlying issue isn't fixed, there's a high chance the code will return.
Why does this code pair with others?
Transmission temperature issues can often trigger multiple fault codes related to fluid temperature and pressure.
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