P08B2Neutral Position Sensor A/B Correlation
- Generic OBD-II code · Powertrain
- How the car detects it
- On a manual gearbox with two neutral sensors or two channels, the engine module compares A and B. P08B2 means they disagree: one reports neutral, the other a gear, or their values differ beyond a calibrated limit, while each may look fine electrically. No manufacturer documents P08B2 publicly. A GM patent describes exactly this layout: two Hall sensors with their own magnets on the shift shaft, whose PWM outputs must be identical in neutral as an integrity check. Audi's G701 and GM's LT5 Corvette use only the A codes. CARB 1968.2 (e)(15) requires rationality monitoring of inputs. Because neutral cannot be confirmed, start-stop and remote start stay off; usual fix is aligning or replacing the sensor.
- What you may notice
- Start-stop unavailable
- Start system warning in the cluster
- Gear indicator may be blank or wrong
- Likely causes
- LikelyOne of the two neutral sensors drifting or faulty
- PossibleMagnet on the shift shaft shifted or sensor misaligned after repair
- PossibleNeutral position not relearned after component replacement
- Repair
- Medium · Usually a job for a workshop.Typical cost: €60 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.