Transmission Fluid Temperature Sensor 1
Transmission Fluid Temperature Sensor 1 circuit fault.
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What it means (plain English)
The Transmission Fluid Temperature Sensor 1 measures the temperature of the transmission fluid to help adjust the transmission's performance. If there's a fault, it may report wrong temperatures, affecting shifting and operation.
What the computer is actually seeing
The ECM detects a voltage from the transmission fluid temperature sensor that is out of the normal operating range, typically a voltage between 0.5V and 4.5V corresponding to fluid temperatures from -40°F to 300°F.
What a healthy reading looks like
Sensor output should be between 0.5V (at -40°F) and 4.5V (at 300°F).
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; should be within the specified range. If low, top up and see if the code clears.
- 22. Inspect the wiring and connectors to the transmission fluid temperature sensor for damage or corrosion. Repair as needed, then test again.
- 33. Use a multimeter to test the voltage output of the transmission fluid temperature sensor: should be between 0.5V and 4.5V. If not, proceed to step 4.
- 44. Replace the transmission fluid temperature sensor if the voltage is out of range. Clear codes and retest operation.
Common causes
- Damaged wiring or connector to the sensor
- Faulty transmission fluid temperature sensor
- Low transmission fluid level
- Corrosion at the connector or sensor terminals
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
Moderate severity means it’s advisable to fix it soon as it can affect drivability, but it may still be drivable short distances.
Will this code come back after clearing?
It could come back if the underlying issue isn't fixed, like a faulty sensor or damaged wiring.
Why does this code appear with other transmission codes?
Transmission temperature is critical for other control functions, so a fault in temperature measurement can impact shift timing and performance.
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