OBD-II code · Powertrain (generic, extended)
P2D1B Exhaust Flow Control Valve C Position Not Learned
The exhaust flow control valve C reports a position not learned condition. Exhaust routing for back-pressure or noise control on this branch cannot be commanded reliably.
Is it safe to drive with P2D1B?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyAdaptation lost after battery disconnect
- PossibleValve replaced without learn procedure
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Likely to fail
- Parts involved
- Exhaust Flow Control Valve C, Wiring Harness, Ecm
Related codes
- P2D11Exhaust Flow Control Valve A Position Not Learned
- P2D12Exhaust Flow Control Valve B Position Not Learned
- P2D18Exhaust Flow Control Valve C Position Circuit Range/Performance
- P2D19Exhaust Flow Control Valve C Position Circuit Low
- P2D1AExhaust Flow Control Valve C Position Circuit High
- P2D1CCold Start EGR A/B Ratio Performance
- P2D1DReductant System Leak Detected – Small Leak
- P2D1EReductant System Leak Detected – Large Leak
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.