What it means
The alternative fuel pump C compression stroke valve control circuit signal 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
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 circuit and sets P2A89 when the signal from pump C’s circuit is lower than expected.
Common causes
Most likely first.
- Control wire shorted to ground
- Internal short in 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 low reading occurs.
- With the ignition off, inspect pump C’s valve wiring for damage or contact with ground, and check the connector for corrosion or loose terminals.
- Check the connector pins for corrosion or poor contact, which can add resistance in the circuit.
- Use the vehicle wiring diagram to test whether the control wire is shorted to ground.
- Measure pump C’s valve coil and circuit using the manufacturer’s procedure to check for an internal short or other out-of-spec result.
Common fixes
- Clean and secure corroded or loose pump C valve connector terminals.
- Repair a control wire shorted to ground.
- Repair damaged wiring or terminal connections in pump C’s valve circuit.
- Replace the compression-stroke valve if its coil is internally shorted or fails the specified test.
Can I keep driving?
Avoid heavy loads and high engine speeds because poor pump C valve control can cause power loss or stalling. If the engine stalls, starts unreliably, or cannot maintain safe power, 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.