What it means
The neutral position sensor B reports a not learned fault. Verification of true neutral position on the B channel is impaired.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Neutral position sensor B supplies a position signal that the transmission control module must learn or adapt before it can use it reliably. This code sets when the B-channel adaptation is missing or was lost, so the module cannot confirm neutral using its learned reference.
Common causes
Most likely first.
- Adaptation lost
- Sensor replaced without learn procedure
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
- Check freeze-frame and transmission data for the not-learned status and note whether the sensor or transmission was recently replaced or serviced.
- Inspect sensor B’s connector and wiring for damage or poor connections that could prevent a learn procedure from completing.
- Confirm the B-channel signal changes as expected with transmission position, using live data and the manufacturer’s specification.
- Check for related transmission or sensor codes that could block the learning process before attempting adaptation.
- If the circuit and signal are sound, perform the manufacturer’s neutral position sensor B learn procedure with the specified prerequisites.
Common fixes
- Correct any sensor B connector or wiring fault that prevents a stable signal.
- Perform the manufacturer’s sensor B adaptation or learn procedure.
- Replace sensor B if it cannot provide a usable signal during learning.
- Repeat the required learn after sensor replacement or related transmission service.
Can I keep driving?
If the transmission shifts normally, drive cautiously and avoid unnecessary trips until the B-channel learn is completed. Stop driving and arrange prompt diagnosis if shifts become harsh, delayed, or the transmission enters limp mode.
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.