Transmission Fluid Temperature Sensor 1 Fault
Problem with the transmission fluid temperature sensor signal.
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What it means (plain English)
The transmission fluid temperature sensor is not sending the correct signal to the engine control module (ECM), which monitors the temperature of the transmission fluid to prevent overheating and ensure proper operation.
What the computer is actually seeing
The ECM sees an out-of-range voltage signal from the transmission fluid temperature sensor, which should typically be between 0.5V and 4.5V depending on the transmission fluid temperature.
What a healthy reading looks like
Ideal transmission fluid temperature should be around 175°F to 220°F while operating. Any reading outside of 0°F to 300°F on the sensor is a concern.
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. Inspect the wiring and connectors at the transmission fluid temperature sensor for damage or corrosion. If damaged, repair or replace and retest.
- 22. Check the transmission fluid level and condition. Low or contaminated fluid could cause incorrect readings. Top off or replace fluid if necessary and retest.
- 33. Using a scan tool, check the voltage output from the transmission fluid temperature sensor. It should be between 0.5V and 4.5V. If not, replace the sensor and retest.
- 44. Verify the operation of the sensor with a thermocouple or infrared thermometer to ensure actual fluid temperatures match the sensor readings. If they don't, replace the sensor.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues (shorts or opens)
- Bad connections at the sensor or ECM
- Contaminated transmission fluid
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not advised to drive long distances as overheating could occur, which may cause transmission damage.
Will this problem come back after fixing?
If underlying issues like wiring problems are not addressed, the code could reappear.
Why does this code pair with SPN 0571?
SPN 0571 typically indicates a second transmission fluid temperature sensor issue; they both monitor the same system.
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