OBD-II code · Powertrain (generic, extended)
P2AA2 Alternative Fuel Return Line Insufficient Flow
The AFCM detects that the flow through the alternative fuel return line is below the expected minimum for the active operating mode. Restricted line, stuck valve, or pump output too low.
Is it safe to drive with P2AA2?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyReturn line restricted by debris
- PossibleReturn line valve stuck closed
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–4 h
- Emissions test
- Likely to fail
- Parts involved
- Alt Fuel Return Line, Alt Fuel Return Line Valve, Alt Fuel Pump
Related codes
- P2A9FAlternative Fuel Return Line Valve Control Circuit Range/Performance
- P2AA0Alternative Fuel Return Line Valve Control Circuit Low
- P2AA1Alternative Fuel Return Line Valve Control Circuit High
- P2AA3Cold Start EGR B Flow Insufficient Detected
- P2AA4Cold Start EGR B Flow Excessive Detected
- P2AA5EGR Cooler Bypass Control Circuit Driver Current/Temperature Too High Bank 1
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.