What it means
The AFCM detects that alternative fuel delivery to the engine deviates from the commanded amount. Pump output, valve actuation, or injector flow does not match expectations.
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 control module (AFCM) manages fuel delivery when a bi-fuel vehicle runs on its alternative fuel. It compares commanded delivery with the system’s response and sets P2A3E when pump output, valve operation, or injector flow does not provide the expected amount. Poor alternative-fuel delivery can cause the module to reduce power or switch the engine back to gasoline.
Common causes
Most likely first.
- Alt fuel pump output degraded
- Alt fuel injectors partially clogged
Symptoms
- Check-engine light
- Loss of power or hesitation
- Poor fuel economy
- Unexpected switch to gasoline
How to diagnose it
- Use a scan tool to record freeze-frame data and AFCM live data, including commanded fuel delivery and whether the system switched to gasoline.
- Check the alternative-fuel warning indicators and verify the tank has usable fuel before investigating delivery components.
- Inspect the alternative-fuel pump, accessible fuel lines, valves, and connectors for damage, loose connections, or signs of leakage.
- Compare alternative-fuel rail pressure and pump response with the commanded values and manufacturer’s specification.
- If pressure and pump operation are correct, test injector flow and valve actuation using the vehicle’s specified diagnostic procedure.
Common fixes
- Restore a loose or damaged alternative-fuel electrical connection.
- Repair or replace the alternative-fuel pump if its output is below specification.
- Service or replace partially clogged alternative-fuel injectors if flow testing confirms restriction.
- Repair a faulty delivery valve if its actuation test fails.
Can I keep driving?
Because the vehicle may lose power or switch unexpectedly to gasoline, avoid overtaking, towing, or other situations where a sudden change in response could be hazardous. If it runs smoothly on gasoline, drive only as needed to arrange diagnosis; stop if power loss becomes severe.
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.