Cause
Faulty alternative fuel tank shutoff valve
The electrically held valve at the outlet of a gaseous fuel tank — LPG, autogas or CNG — has failed, seized, or lost its control circuit.
It is a safety device, and reading it as a fuel valve underplays what it is for. A gaseous fuel tank holds its contents under real pressure: around 8 bar for LPG on a warm day, up to 200 bar for compressed natural gas. A petrol tank leaks a puddle; a gas tank leaks continuously and invisibly until something ignites it. So the tank outlet carries a valve that is held open electrically, wired so that it closes whenever it loses power — engine off, ignition off, crash sensor triggered, or any fault in its own circuit.
That fail-closed design is why this failure has no middle state. The valve is either held open or the tank is isolated; there is no limp mode. On a bi-fuel car the engine simply reverts to petrol and keeps running, which is why the complaint that reaches a workshop is "it will not run on gas any more" rather than anything alarming.
And it is why the fault is easy to live with and worth not living with. A circuit that intermittently fails to hold the valve open is the same circuit relied on to close it on demand. The half nobody notices is the half that matters.
Two practical notes. These installations are usually aftermarket, so the letter in the code maps to a physical tank only in the installer's documentation — a car may carry a toroidal tank in the spare wheel well and a cylinder in the load space, each with its own valve. And the work belongs with a gas installer rather than a general workshop: the tank must be handled correctly before anything at its outlet is disturbed.
Typically specialist work. Needs equipment or training most home workshops do not have.
Codes this can cause (20)
Codes where this is a likely explanation first, rather than merely a possible one.
- P2A22 Alternative Fuel Tank Shutoff Valve B Control Circuit/Open Likely for this code High
- P2A23 Alternative Fuel Tank Shutoff Valve B Control Circuit Performance/Stuck Off Likely for this code High
- P2A24 Alternative Fuel Tank Shutoff Valve B Control Circuit Low Likely for this code High
- P2A25 Alternative Fuel Tank Shutoff Valve B Control Circuit High Likely for this code High
- P2A26 Alternative Fuel Tank Shutoff Valve C Control Circuit/Open Likely for this code High
- P2A27 Alternative Fuel Tank Shutoff Valve C Control Circuit Performance/Stuck Off Likely for this code High
- P2A28 Alternative Fuel Tank Shutoff Valve C Control Circuit Low Likely for this code High
- P2A29 Alternative Fuel Tank Shutoff Valve C Control Circuit High Likely for this code High
- P2A2A Alternative Fuel Tank Shutoff Valve D Control Circuit/Open Likely for this code High
- P2A2B Alternative Fuel Tank Shutoff Valve D Control Circuit Performance/Stuck Off Likely for this code High
- P2A2C Alternative Fuel Tank Shutoff Valve D Control Circuit Low Likely for this code High
- P2A2D Alternative Fuel Tank Shutoff Valve D Control Circuit High Likely for this code High
- P2A2E Alternative Fuel Tank Shutoff Valve E Control Circuit/Open Likely for this code High
- P2A2F Alternative Fuel Tank Shutoff Valve E Control Circuit Performance/Stuck Off Likely for this code High
- P2A30 Alternative Fuel Tank Shutoff Valve E Control Circuit Low Likely for this code High
- P2A31 Alternative Fuel Tank Shutoff Valve E Control Circuit High Likely for this code High
- P2A3E Alternative Fuel Delivery Error Likely for this code High
- P2A6E Alternative Fuel Rail Pressure Regulator Inlet Pressure Too Low High
- P2A6F Alternative Fuel Rail Pressure Regulator Inlet Pressure Too High High
- P2A9D Alternative Fuel High Pressure System Small Leak High
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
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