P26B5Fuel Shutoff Valve B Control Circuit Performance/Stuck Off
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- With P26B5 shut-off valve B fails to open or pass fuel when commanded. Roush CleanTech documents the code for its Gen 4 propane system on 2016–2018 Ford trucks, where valve B is the supply solenoid in the module that regulates rail pressure (its circuit code there is P2665). Once a start is initiated, the system module checks how far rail pressure climbs; too small an increase stores P26B5. Listed causes include a tripped excess flow valve, a manual valve not fully open, a tank or supply solenoid that does not open, weak pumps, a blocked filter or kinked lines. The engine then cranks without starting or runs poorly, as the system cycles pumps and solenoids to build pressure. MIL status varies by model. P26B6 is the stuck-on case.
- What you may notice
- Engine cranks but does not start, or runs poorly
- Long start sequence with pumps cycling repeatedly
- Check engine light on some models
- Likely causes
- LikelySupply or tank solenoid not opening
- PossibleManual valve partly closed or excess flow valve tripped
- PossibleWeak fuel pumps, clogged filter or kinked lines
- RareBlown fuse in the valve circuit
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €1,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.