What it means
The alternative fuel rail pressure regulator inlet pressure is higher 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 controls fuel pressure supplied to the rail, and the control module monitors pressure at its inlet. P2A6F sets when inlet pressure is higher than expected, which can disrupt regulation and alternative-fuel operation.
Common causes
Most likely first.
- Pump pressure regulator stuck high
- Restriction downstream of regulator
Symptoms
- Check-engine or alternative-fuel system warning light
- Rough running or hesitation on alternative fuel
- Alternative-fuel operation may be limited
How to diagnose it
- Capture freeze-frame data and use live scan data to confirm the inlet pressure is high when the fault occurs.
- Inspect the alternative-fuel lines downstream of the regulator for kinks, damage, or other signs of restriction.
- Check the pump pressure regulator and its connections for damage or signs that the regulator is stuck in a high-pressure condition.
- Compare measured inlet pressure and commanded operation with the manufacturer's specification using the approved test procedure.
- If pressure readings conflict with observed fuel delivery, check the pressure sensor circuit before replacing pressure-control parts.
Common fixes
- Clear a restriction by repairing or replacing a damaged or obstructed downstream fuel line using the manufacturer's procedure.
- Repair loose or damaged regulator wiring or connections.
- Replace a pump pressure regulator that testing confirms is stuck high.
- Replace a faulty pressure sensor only if its circuit and pressure reading tests identify it as the cause.
Can I keep driving?
Avoid hard acceleration or continued alternative-fuel use if the engine runs roughly or hesitates, since incorrect pressure can worsen drivability and emissions. Switch to another available fuel mode if the vehicle supports it and runs normally.
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.