What it means
The alternative fuel rail pressure regulator inlet pressure is lower than expected.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
The alternative-fuel rail pressure regulator receives fuel from the upstream supply, and the control module monitors pressure at the regulator inlet. P2A6E sets when that inlet pressure falls below the expected level, which can limit alternative-fuel delivery.
Common causes
Most likely first.
- Alt fuel tank near empty
- Alt fuel pump output low
Symptoms
- Check-engine or alternative-fuel system warning light
- Loss of power or hesitation on alternative fuel
- Alternative-fuel operation may be limited
How to diagnose it
- Use a scan tool to capture freeze-frame data and compare alternative-fuel inlet pressure with commanded conditions when the code set.
- Check the alternative-fuel tank level and confirm the system is operating on that fuel, since a near-empty tank can reduce supply pressure.
- Inspect the alternative-fuel pump, its electrical connections, and supply lines for damage or loose connections.
- Use scan-tool live data to see whether inlet pressure stays low during operation, and compare the reading with the manufacturer's specification.
- Test alternative-fuel pump supply and output using the manufacturer's procedure to distinguish weak pump delivery from a pressure-sensing or supply problem.
Common fixes
- Refill the alternative-fuel tank if it is near empty.
- Repair a loose or damaged pump connector or supply line.
- Restore the pump's electrical supply if testing finds a connection fault.
- Replace the alternative-fuel pump if its output is below the manufacturer's specification.
Can I keep driving?
Avoid relying on alternative fuel or demanding acceleration if the vehicle hesitates or loses power; the system may restrict that fuel mode or the engine may stall. If it runs normally on another fuel mode, use that mode until diagnosed.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.