What it means
The second transmission fluid temperature sensor reading is implausible against engine load and ambient temperature. Drift or stuck signal.
At a glance
- Usually lights the check-engine light
How it works
Transmission fluid temperature sensor B measures fluid temperature at its monitored location, and the transmission control module checks whether that reading makes sense over time and against operating conditions. This code sets when sensor B’s signal is electrically plausible but its temperature reading does not match expected changes with engine load or ambient temperature.
Common causes
Most likely first.
- Sensor drift after thermal aging
- Sensor not seated properly in the fluid path
- Sensor element aged beyond calibration window
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
How to diagnose it
- Review freeze-frame data and graph sensor B temperature during warm-up to see whether it rises smoothly and plausibly.
- After a cold soak, compare sensor B’s reading with ambient temperature and other available transmission temperature readings.
- Inspect sensor B’s seating and connector for looseness, contamination, or poor contact that could distort the reading.
- Check the harness for damage and test the sensor B circuit for stable connections while monitoring its live reading.
- If wiring and seating are sound, test sensor B against the manufacturer’s temperature-to-signal procedure for drift or a stuck output.
Common fixes
- Reseat sensor B correctly in the fluid path if it is loose or improperly installed.
- Repair a poor connector contact or damaged wiring affecting sensor B’s reading.
- Replace sensor B if its reading remains implausible despite a sound circuit.
- Clear the code and confirm that sensor B tracks temperature plausibly through a warm-up.
Can I keep driving?
If shifting is normal, drive gently and avoid towing until the temperature reading is verified. Stop if shifts become unreliable or the transmission warns of overheating, since an implausible sensor B reading can interfere with shift control.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.