OBD-II code · Powertrain (generic, extended)
P25BF Alternative Fuel Disable Control Circuit High
Voltage on the alternative-fuel disable control line is above the expected window. Often a short to battery upstream of the relay or a stuck-on driver in the control module.
Is it safe to drive with P25BF?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyDisable control wire shorted to a B+ supply
- PossibleOutput driver stuck on inside the control module
- Less likelyConnector pins corroded - high contact resistance
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.8–2 h
- Emissions test
- Usually unaffected
- Parts involved
- Alt Fuel Control Module, Wiring Harness
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.