OBD-II code · Powertrain (generic)
P01B1 Alternative Fuel Tank A Level Sensor Circuit Low
Alt fuel tank A level sensor signal voltage below expected range. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P01B1?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal wire shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Usually unaffected
- Parts involved
- Alt Fuel Tank Level Sensor, Sensor Wiring
Related codes
- P2A61Alternative Fuel Tank B Level Sensor Circuit Low
- P2A66Alternative Fuel Tank C Level Sensor Circuit Low
- P01AEAlternative Fuel Tank Temperature Sensor Circuit Intermittent/Erratic
- P01AFAlternative Fuel Tank A Level Sensor Circuit
- P01B0Alternative Fuel Tank A Level Sensor Range/Performance
- P01B2Alternative Fuel Tank A Level Sensor Circuit High
- P01B3Alternative Fuel Tank A Level Sensor Circuit Intermittent/Erratic
- P01B4Alternative Fuel Rail Temperature Sensor Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.