Transmission Fluid Temperature Sensor 1
Indicates a problem with 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 to ensure proper operation; if it's malfunctioning, it can lead to transmission overheating or poor shifting.
What the computer is actually seeing
The computer looks for a voltage signal from the transmission fluid temperature sensor, typically around 0.5V to 4.5V, which corresponds to fluid temperatures of -40°C to 150°C (-40°F to 302°F).
What a healthy reading looks like
Expect a voltage between 0.5V (cold) and 4.5V (hot) from the sensor under normal operating conditions; a reading outside this range usually 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. Check the transmission fluid level; it should be within the correct range. If low, top it off and clear the code.
- 22. Inspect the wiring and connectors at the transmission fluid temperature sensor for damage or corrosion.
- 33. Measure the voltage at the sensor while the engine is running; it should be between 0.5V and 4.5V based on fluid temp. If not, replace the sensor.
- 44. If the sensor voltage is within range but code returns, consider testing or replacing the transmission control module (TCM).
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues or damaged connectors to the sensor
- Low transmission fluid level or contaminated fluid
- Faulty transmission control module (TCM)
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's advisable to address this issue soon since it can lead to transmission overheating and damage.
Will the code come back after clearing it?
If the issue isn't fixed, it will likely return after a short drive.
Why might this code appear with other codes?
It can be linked to other transmission-related issues or sensors, like problems with the transmission control module.
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