Powertrain, generic (extended)

P2A22 Alternative Fuel Tank Shutoff Valve B Control Circuit/Open

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P2A22 covers the drive circuit of shutoff valve B, the electric lock on a further gas cylinder of a multi-tank CNG or LPG installation, when the module finds no current path at all. A broken lead, a loose plug or a burnt-out coil are the usual findings. No manufacturer documents P2A22 publicly; the upfitter TransEco lumps an open line into its Low code P2A24 instead. New Flyer's CNG bus bulletin SMB-169 suggests a quick test for a dead tank solenoid: swap its coil with the one from a neighbouring valve. CARB's comprehensive component rules require such outputs to be checked for wiring faults. With one cylinder isolated, the remaining tanks still feed the engine, so reduced range is often the first thing a driver notices.

Likely causes

Broken lead or disconnected plug at the valve on tank B
Burnt-out solenoid coil of valve B
Corroded terminals in the valve connector

Symptoms

  • Check engine light
  • Noticeably shorter range on gas
  • Gas left in one cylinder after the others are empty

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–1,200
Time0.5–3 h

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

Parts involved

alt fuel tank shutoff valve bwiring harnessafcm

Related codes

P2A23P2A24P2A25P2A26P224C

References: law.cornell.edu, static.nhtsa.gov, http:.