Transmission Fluid Temperature Sensor
Indicates an issue with the transmission fluid temperature sensor.
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What it means (plain English)
The transmission fluid temperature sensor measures how hot the fluid is inside the transmission. If it’s too high or too low, it can affect how the transmission shifts and performs.
What the computer is actually seeing
The ECM expects the transmission fluid temperature to be between 140°F and 210°F. If the sensor readings vary significantly from this range, it triggers the fault code.
What a healthy reading looks like
Normal operation should show a fluid temperature between 140°F and 200°F, with a sensor voltage output typically between 0.5V to 4.5V depending on the 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 transmission fluid level; it should be at the proper mark on the dipstick. If low, top off fluid and retest.
- 22. Inspect the wiring and connectors to the transmission fluid temperature sensor for damage, corrosion, or loose connections.
- 33. Using a scan tool, monitor the live data for the transmission fluid temperature. Compare the readings to expected values.
- 44. If the readings are significantly outside the normal range or fluctuate wildly, replace the transmission fluid temperature sensor.
- 55. Clear the code and retest. If the code returns, consider checking the ECM for software updates or internal faults.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues or shorts in the sensor circuit
- Low transmission fluid level
- Faulty ECM software or calibration
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderate severity; you can drive, but shifting may be affected, so fix soon.
Will this code come back after resetting?
If the underlying issue isn’t resolved, yes, it will likely return.
Why does this code sometimes pair with SPN 564?
SPN 564 indicates a fault with the transmission fluid temperature sensor circuit, often linked to the same wiring or sensor issues.
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