Transmission Fluid Temperature Sensor 1
Indicates a fault with the transmission fluid temperature sensor.
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What it means (plain English)
The transmission fluid temperature sensor measures the temperature of the transmission fluid to ensure it’s at the right level for proper operation. If the reading is off, it could mess up shifting or cause overheating.
What the computer is actually seeing
The vehicle's computer expects the transmission fluid temperature to be within a specific range based on operating conditions. If the temperature sensor sends a signal indicating a fault, such as an open circuit or a temperature out of range (like below -40°C or above 150°C), the code triggers.
What a healthy reading looks like
Transmission fluid temperature should be between 60°C and 100°C (140°F to 212°F) when operating normally under load.
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 recommended range.
- 22. Inspect wiring and connectors to the transmission fluid temperature sensor for damage or corrosion. Repair as needed.
- 33. Use a multimeter to check the resistance of the temperature sensor. It should vary within a given range typically around 2k-15k ohms (depending on temperature).
- 44. Clear the code and run the vehicle to monitor the sensor's behavior. Check if the code returns after running.
- 55. If the code returns after following steps 1-4, consider replacing the temperature sensor.
Common causes
- Faulty transmission fluid temperature sensor
- Damaged wiring or connectors
- Low transmission fluid level
- Faulty engine control module (ECM)
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Drivability may be affected due to potential overheating. It's best to fix soon.
Will this code come back after clearing it?
If the underlying issue isn't resolved, such as a bad sensor or wiring, the code will likely return.
Why does this code pair with SPN 2109?
SPN 2109 is related to the transmission fluid temperature sensor, indicating faults in the same system.
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