Transmission Fluid Temperature Sensor 1
This code indicates an issue with the transmission fluid temperature sensor 1.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The computer is detecting that the temperature sensor in the transmission isn't reading correctly, which can affect shifting and overall transmission operation.
What the computer is actually seeing
The Transmission Control Module (TCM) is supposed to receive a voltage signal from the temperature sensor that reflects the fluid temperature. Typically, a good sensor signal should range from 0.5 volts (around 32°F or 0°C) to 4.5 volts (around 240°F or 116°C).
What a healthy reading looks like
Expect sensor voltage between 0.5V to 4.5V according to fluid temperature; below 0.5V or above 4.5V indicates a problem.
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.
- 1Check the transmission fluid level; it should be in the proper range for the specific vehicle.
- 2Inspect wiring and connectors to the transmission fluid temperature sensor for any visible damage or corrosion.
- 3Using a multimeter, measure the voltage at the transmission fluid temperature sensor connector while the engine is running; should be 0.5V to 4.5V.
- 4If voltage is out of range, replace the temperature sensor and retest.
- 5If the voltage is within range, scan the TCM for additional stored codes and proceed with further diagnosis.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues (shorts, opens, corrosion)
- Poor connection at the sensor or TCM
- Fluid level too low or too high
- TCM malfunction
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's better to fix this soon, as incorrect transmission temperatures affect shifting and can lead to increased wear.
Will the code come back if I clear it?
If the underlying issue isn't fixed, the code will likely return.
Why does this code sometimes appear with SPN 3023?
SPN 3023 is for the second temperature sensor, so if there's an issue with one, the other may be affected too.
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