Powertrain, generic (extended)

P26B5 Fuel Shutoff Valve B Control Circuit Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

Supply or tank solenoid not opening
Manual valve partly closed or excess flow valve tripped
Weak fuel pumps, clogged filter or kinked lines
Blown fuse in the valve circuit

Symptoms

  • Engine cranks but does not start, or runs poorly
  • Long start sequence with pumps cycling repeatedly
  • Check engine light on some models

Repair estimate

DifficultyHardWorkshop job
Parts and labour€100–1,000
Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

fuel shutoff valve bsolenoid

Related codes

P26B6P26B3P2665P2666P2667

References: roushcleantech.com, law.cornell.edu, static.nhtsa.gov.