OBD-II code · Powertrain (manufacturer / generic)
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.
Is it safe to drive with P3478?
Usually safe for short trips, but don’t ignore it: the underlying fault can get more expensive over time.
Common causes
- Most likelyPressure switch sticky or contaminated
- PossibleOil control valve slow to respond
- Less likelyLow system oil pressure
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Oil Pressure Switch, Oil Control Valve
Related codes
- P3476Cylinder Deactivation Oil Pressure Switch Bank 1 Performance
- P3475Cylinder Deactivation Oil Pressure Switch Bank 1 Circuit
- P3477Cylinder Deactivation Oil Pressure Switch Bank 2 Circuit
- P3479Cylinder Deactivation Solenoid Bank 1 Control Circuit Open
- P3480Cylinder Deactivation Solenoid Bank 2 Control Circuit Open
- P3481Cylinder 10 Deactivation
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.