OBD-II code · Powertrain (generic, extended)
P2D12 Exhaust Flow Control Valve B Position Not Learned
The ECM has not learned the end-stop calibration for exhaust flow control valve B. Position cannot be commanded with full precision until adaptation completes.
Is it safe to drive with P2D12?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyAdaptation lost after battery disconnect or ECM reset
- PossibleValve replaced without learn procedure
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.3–1.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Exhaust Flow Control Valve B, Ecm
Related codes
- P2D11Exhaust Flow Control Valve A Position Not Learned
- P2D1BExhaust Flow Control Valve C Position Not Learned
- P2D0FEngine Pre-Ignition Above Threshold
- P2D10Engine Pre-Ignition Above Threshold - Forced Limited Power
- P2D13Exhaust Flow Control Valve C Control Circuit/Open
- P2D14Exhaust Flow Control Valve C Control Circuit Low
- P2D15Exhaust Flow Control Valve C Control Circuit High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.