Transmission Fluid Temperature Sensor High
The transmission fluid temperature sensor is reporting high readings.
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What it means (plain English)
The temperature sensor in the transmission is telling the computer that the fluid is too hot, which can damage the transmission if not checked quickly.
What the computer is actually seeing
The engine control module (ECM) receives a voltage signal from the transmission fluid temperature sensor, which should range from 0.5V (cold) to 4.5V (hot). If the voltage is consistently above 4.5V, the code sets.
What a healthy reading looks like
Transmission fluid temperature should ideally be between 175°F and 220°F (79°C - 104°C) during normal operation, with a sensor voltage of 1V to 3V corresponding to this range.
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; add fluid if low (ideal level between ADD and FULL).
- 22. Inspect the wiring and connectors to the transmission temperature sensor for damage or corrosion; repair as needed.
- 33. Measure the voltage at the sensor connector with the ignition on and the engine off—should be between 0.5V and 4.5V. If not, replace the sensor.
- 44. If voltage is good, start engine and monitor the temperature reading via scan tool—should stabilize between 175°F and 220°F (79°C - 104°C). If it reads too high or erratic, check for fluid contamination or a high fluid level. If there's still an issue, suspect the ECM.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues (short circuit or open circuit)
- Transmission fluid contamination or low level
- Faulty ECM programming
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means you can drive the vehicle, but inspect and resolve the issue soon to avoid damage.
Will this code come back after clearing?
It may return if the underlying issue is not fixed; monitor sensor readings after repairs.
Why do I see this code with other transmission codes?
Codes like SPN 1210 or SPN 111 relate to the same system; high temperature can cause other transmission performance issues.
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