P340D
Deactivation/Exhaust Valve Control Circuit Bank 2
Generic electrical fault on the cylinder deactivation/exhaust valve control circuit on bank 2. The exhaust control valve modulates exhaust backpressure or routing (EGR feed, sound, regen support); a malfunction shifts torque mapping and may trigger limp mode.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- Deactivation solenoid failedCommon
- Wiring break or unplugged connectorPossible
Parts involved
- Cylinder Deactivation Solenoid
- Actuator Wiring
P340D is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.