OBD-II code · Powertrain (generic)
P04B1 Refueling Vapor Control Valve Circuit Low
Same as P04B0 with the control line shorted to ground. 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 P04B1?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyControl line shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.8–1.8 h
- Emissions test
- Likely to fail
- Parts involved
- Refueling Vapor Valve
Related codes
- P04AEEVAP System Purge Control Valve B Performance Stuck Open
- P04AFEVAP System Purge Control Valve B Stuck Closed
- P04B0Refueling Vapor Control Valve Circuit Open
- P04B2Refueling Vapor Control Valve Circuit High
- P04B3Refueling Vapor Control Valve Performance Stuck Open
- P04B4Refueling Vapor Control Valve Stuck Closed
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.