P2A91 code meaning
Alternative Fuel Tank Select Valve A Control Circuit/Open
Powertrain system Generic code P2Axx codes Check engine light
What P2A91 means
A tank select valve decides which storage vessel feeds the fuel system. That sets it apart from a tank shutoff valve (P224C, P2A22 and onward), which simply opens or isolates one cylinder, and from the hydraulic fuel pump select valve (P2A70 and onward), which routes drive oil to a pump. Westport's patent US8726785B2 shows the idea with two LNG vessels and one external pump, where an insulated valve links the pump to either vessel. P2A91 means the control circuit of select valve A is open or otherwise faulty, so the valve stays in its rest position. Fuel is then drawn only from the vessel reached in that position and the rest may become unusable. No manufacturer documents P2A91 publicly; CARB requires output circuits to be checked for continuity.
P2A91 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2A91
- Malfunction lamp on
- Only one tank is used, range noticeably shorter
- Fuel gauge shows content left although the engine runs short of gas
Common causes of P2A91
- Most likelyLoose connector or broken wire to select valve A
- PossibleBurnt-out solenoid coil of valve A
- Less likelyFaulty output stage in the alternative fuel module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Alt fuel tank select valve aWiring harnessAfcm
What each part of P2A91 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| A | Area: hybrid propulsion. |
| 91 | The exact fault in that area. |
What to do next
- Note P2A91 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P2A91
What does P2A91 mean?
P2A91 means "Alternative Fuel Tank Select Valve A Control Circuit/Open". A tank select valve decides which storage vessel feeds the fuel system. It is a generic code, so it means the same on every make.
Is it safe to drive with P2A91?
Drive gently and only to a workshop. With P2A91 the car can go into limp mode (reduced power) to protect itself.
Will P2A91 fail an emissions test?
Yes, it can. P2A91 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P2A91 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P2A91 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.