Transmission Fluid Temperature Sensor 1
Indicates a high transmission fluid temperature.
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What it means (plain English)
The transmission fluid temperature sensor measures how hot the transmission fluid is. If it's too high, it can mean the fluid is overheating, which can lead to transmission damage.
What the computer is actually seeing
The Engine Control Module (ECM) monitors the voltage signal from the transmission fluid temperature sensor. A typical voltage range is 0.5V to 4.5V; values above 5V or below 0V can trigger a fault code. The ECM expects fluid temperatures between 70°C to 120°C (158°F to 248°F) during normal operation.
What a healthy reading looks like
Transmission fluid temperatures should be between 70°C to 120°C (158°F to 248°F). Voltages from the sensor should be between 0.5V and 4.5V.
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 proper range as per manufacturer specifications.
- 22. Inspect the wiring and connectors for any damage or corrosion. Repair if necessary.
- 33. Use a scan tool to monitor the live data from the transmission fluid temperature sensor. Check if it reflects the actual temperature of the fluid.
- 44. If the readings are out of range, replace the temperature sensor and clear the code. After replacing, recheck the fluid temperature using the scan tool.
Common causes
- Faulty transmission fluid temperature sensor
- Wiring issues (frayed or shorted wires)
- Loose or corroded connector terminals
- Low transmission fluid level
- Contaminated transmission fluid
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive my vehicle with this code?
It's drivable but may cause transmission damage if ignored. Monitor fluid temps closely.
Will this code come back if I fix the sensor?
If the issue was solely the sensor, clearing the code should prevent it from returning. Other issues may cause reoccurrence.
Why does this code appear with transmission slipping?
High transmission fluid temps can lead to slipping; the code indicates potential overheating, which may cause performance issues.
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