Powertrain, generic (extended)

P2A23 Alternative Fuel Tank Shutoff Valve B Control Circuit Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P2A23 is stored when valve B is switched on electrically, but the gas system does not react as if that cylinder had opened. Software can only judge this from pressure: after the command, the reading downstream of the tank should rise, and a tank B pressure sensor, where fitted, should fall while gas is being used. No manufacturer publishes P2A23 or its thresholds. Bus maker New Flyer devotes bulletin SMB-169 to a tank solenoid stuck closed and explains how such a cylinder is vented through the purge line before the valve is replaced. Likely reasons are a jammed armature, a closed hand valve on that tank or debris. P2A22, P2A24 and P2A25 cover the electrical faults of the same valve, P2A42 the plausibility of its pressure sensor.

Likely causes

Armature of valve B jammed closed, e.g. by debris
Manual valve on tank B left closed
Tank or line pressure sensor reporting the response wrongly

Symptoms

  • Check engine light
  • Tank B stays full while the others empty
  • Reduced range on gas

Repair estimate

DifficultyHardWorkshop job
Parts and labour€80–1,500
Time0.5–4 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

P2A22P2A24P2A25P2A42P224D

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