P3434
Cylinder 4 Deactivation Stuck Off
The engine control module has detected that cylinder 4 deactivation hardware is stuck in the off state. The deactivation cannot be released when full-cylinder operation is commanded.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- Lifter stuck collapsedCommon
- Solenoid stuckPossible
- Carbon or debris buildup preventing free movementLess likely
Parts involved
- Cylinder Deactivation Solenoid
- Lifter
P3434 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.