Transmission Fluid Temperature Sensor Circuit
The transmission fluid temperature sensor is indicating a fault.
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What it means (plain English)
The computer checks the transmission fluid temperature to make sure it's within normal limits. If the sensor is sending bad data, the system may think the transmission is overheating or too cool, which can cause poor shifting or damage.
What the computer is actually seeing
The transmission control module is looking for a resistance change in the temperature sensor circuit. Normally, a well-functioning sensor will change resistance with temperature, typically between 150mV to 5V depending on its design.
What a healthy reading looks like
Expected fluid temperature range is usually 70°C to 100°C (158°F to 212°F). Should read 0.5V to 4.5V at the sensor under normal conditions.
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 marked range. If it's low, top it up and recheck for codes.
- 22. Inspect the wiring and connectors at the transmission fluid temperature sensor for damage or corrosion. Repair as needed. Retest the system.
- 33. Using a multimeter, check the voltage at the sensor connector; it should be within 0.5V to 4.5V while the engine is running. If not, continue to step 4.
- 44. Disconnect the sensor and test its resistance according to the specifications (usually should change with temperature). Replace the sensor if it fails the test.
Common causes
- Faulty transmission fluid temperature sensor
- Damaged wiring or connectors
- Low transmission fluid level
- Short or open circuit in the sensor's wiring
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
If you notice issues like slipping or hard shifting, it's best to get it checked soon; otherwise, it may still be drivable.
Will this problem come back after fixing?
If the underlying issue is resolved (e.g., sensor replaced, wiring repaired), it shouldn’t come back.
Why does this code pair with SPN 1542?
SPN 1542 also relates to transmission temperature but may indicate a different fault in the circuit, which is why they can appear together.
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