P3478
Cylinder Deactivation Oil Pressure Switch Bank 2 Performance
The engine control module has detected a rationality fault between commanded oil pressure and the bank 2 cylinder deactivation oil pressure switch state. The switch fails to change state at the expected pressure threshold during deactivation transitions on bank 2.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Common causes
Ordered by how often each turns out to be the cause.
- Pressure switch sticky or contaminatedCommon
- Oil control valve slow to respondPossible
- Low system oil pressureLess likely
Parts involved
- Oil Pressure Switch
- Oil Control Valve
P3478 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.