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.
High severity. Can I keep driving?If you smell gas, do not keep driving or start the engine: move away and call for assistance. With no smell, drive moderately to an authorized shop.
Symptoms
- Check engine light
- Tank B stays full while the others empty
- Reduced range on gas
Most 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
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: hard
- It affects emissions.
What each character of P2A23 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- A: Hybrid or air and fuel
- 23: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2A23?
If you smell gas, do not keep driving or start the engine: move away and call for assistance. With no smell, drive moderately to an authorized shop.
What causes code P2A23?
The most common causes are: 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.
Related codes
- P2A22Alternative Fuel Tank Shutoff Valve B Control Circuit/Open
- P2A24Alternative Fuel Tank Shutoff Valve B Control Circuit Low
- P2A25Alternative Fuel Tank Shutoff Valve B Control Circuit High
- P2A42Alternative Fuel Tank B Pressure Sensor Range/Performance
- P224DAlternative Fuel Tank Shutoff Valve A Control Circuit Performance/Stuck Off
Sources
- law.cornell.edu: 13 CCR 1968.2
- static.nhtsa.gov: MC 10110652 9999
- static.nhtsa.gov: INRD PE08063 33504P
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.