Transmission Fluid Temperature Sensor
Indicates a fault in the transmission fluid temperature sensor circuit.
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What it means (plain English)
The transmission fluid temperature sensor measures how hot the fluid is in the transmission; if it’s faulty, the computer can’t get proper readings and might not shift correctly.
What the computer is actually seeing
The engine control module (ECM) looks for a voltage signal from the transmission fluid temperature sensor, typically between 0.5V (cold) to 4.5V (hot). If the voltage is out of range, it triggers the fault code.
What a healthy reading looks like
Expect 0.5V at around 32°F (0°C) and 4.5V at about 194°F (90°C); normal operating range is typically 175°F to 225°F (80°C to 110°C).
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 transmission fluid level; if low, top off and retest. Decision: Is fluid level adequate? Yes: go to step 2; No: fix fluid leak and retest.
- 2Inspect wiring and connectors to the transmission fluid temperature sensor for damage or corrosion. Decision: Are connections secure and undamaged? Yes: go to step 3; No: repair or replace wiring/connectors and retest.
- 3Use a scan tool to monitor the transmission fluid temperature sensor voltage while the engine is running. Decision: Is the voltage reading within expected values? Yes: possible ECM issue; No: replace the transmission fluid temperature sensor and retest.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues or damaged connectors
- Low transmission fluid level
- Broken ECM or software issue
- Corrosion or dirt at the sensor connection
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
You can drive but shifting may be affected, so monitor performance closely.
Will the code come back after repair?
If the underlying problem is resolved, the code should not return.
Why does this code appear with other transmission codes?
They often relate to system performance issues; a faulty sensor can cause multiple related codes.
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