What it means
The alternative fuel pump C compression stroke valve control circuit signal 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
Alternative fuel pump C uses a compression-stroke valve to control fuel delivery during that part of the pump cycle. The control module monitors the valve’s electrical circuit and sets P2A8A when it detects a signal higher than expected for pump C.
Common causes
Most likely first.
- Control wire shorted to B+
- Open valve coil
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Hard start, no start, or stalling under load
- Power loss especially at high load or rpm
- Possible long cranking time
How to diagnose it
- Save the freeze-frame data and check live data for pump C’s valve command or circuit status to see when the high reading occurs.
- With the ignition off, inspect pump C’s valve connector and wiring for corrosion, damaged insulation, loose terminals, or contact with a power feed.
- Check the connector pins for corrosion or poor contact, since added resistance can make the circuit signal appear high.
- Use the vehicle wiring diagram to test the control wire for an unintended connection to battery positive.
- Measure pump C’s valve coil and circuit continuity using the manufacturer’s procedure and compare results with its specification.
Common fixes
- Clean and secure corroded or loose pump C valve connector terminals.
- Repair a control wire shorted to battery positive.
- Repair damaged wiring or terminal connections in pump C’s valve circuit.
- Replace the compression-stroke valve if its coil is open or it otherwise fails the specified circuit test.
Can I keep driving?
Avoid heavy acceleration and high engine speeds because fuel delivery may fall short and cause power loss or stalling. If it stalls, is difficult to start, or cannot maintain power safely, stop driving and arrange repair.
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.