P2A6C: Alternative Fuel Rail Pressure Regulator Inlet Pressure Sensor Circuit High
What to do
The car will run on petrol or on gas with worse economy. If it has been converted for a while and nobody knows when the gas filter was last changed, ask — a restricted filter shows up here, and it is a service item people forget a conversion has.
What this code means
The circuit for the pressure sensor at the regulator's inlet is faulty.
This sensor sits between the tank and the regulator, and what it measures is the pressure the regulator has to work with rather than the pressure the injectors get.
A gas system has two pressure stages. Tank pressure varies enormously — with temperature, with how full the tank is, and with which fuel is in it. The regulator's job is to turn that moving number into a steady rail pressure the injectors can be calibrated against. Its inlet pressure is therefore the raw material.
Which makes this reading the one that catches a restriction. Tank pressure is measured at the tank (P2A41); inlet pressure is measured after the line, the filter and the shutoff valve. A healthy tank pressure with a low inlet pressure means something between them is blocked — and on a system nobody has serviced, that is very often the filter.
No other code in the range localises a restriction that precisely, which is why a low inlet pressure is worth more diagnostically than it looks.
At or above the upper limit.
Likely causes
Start here
- Faulty alternative fuel pressure sensor · specialist
- Corroded or loose connector · specialist
- Open circuit in sensor wiring · specialist
Less common
- Restricted alternative fuel filter · moderate
- Damaged wiring harness · specialist
Symptoms
Components involved
Information, not instruction
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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.
Community experience
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