Transmission Fluid Temperature Sensor 1
Transmission fluid temperature sensor is out of range.
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What it means (plain English)
The transmission fluid temperature sensor measures how hot the fluid is. If it reads too high or too low, the computer thinks something’s wrong with either the sensor or the transmission itself.
What the computer is actually seeing
The engine control module (ECM) or transmission control module (TCM) expects the transmission fluid temp to be around 175°F (79°C) under normal operation. If the reading is below 90°F (32°C) or above 250°F (121°C), it triggers this code.
What a healthy reading looks like
Expected transmission fluid temperature is normally between 175°F (79°C) and 220°F (104°C).
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.
- 1Check transmission fluid level. If low, top it up and recheck for the code.
- 2Inspect wiring and connectors at the temperature sensor for damage or corrosion. Repair as needed and test.
- 3Measure voltage at the transmission fluid temperature sensor; it should produce a signal between 0.5V (cold) to 4.5V (hot). If out of this range, replace the sensor.
- 4Use a scan tool to read the transmission fluid temperature live data and compare it to ambient temperature; if they differ drastically, replace the sensor.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues or short circuits
- Fluid level too low
- Faulty transmission control module (TCM)
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code present?
It’s moderate severity; you can drive it but should address it soon to avoid transmission damage.
Will this code come back after clearing?
If the underlying issue isn’t fixed, yes, the code will return.
Why does this code sometimes appear with SPN 1516?
Both codes relate to transmission fluid temperature issues; one might appear if the sensor is faulty or has connectivity issues.
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