OBD-II code · Powertrain (manufacturer / generic)
P3491 Cylinder Deactivation System Performance Bank 2
The engine control module has detected that the cylinder deactivation system on bank 2 is not performing as expected. Closed-loop monitoring of pressure response, valve timing or misfire counters during transitions indicates the system fails to deactivate or reactivate cylinders within calibrated limits.
Is it safe to drive with P3491?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySwitching lifter stuck or worn
- PossibleInsufficient oil pressure
- PossibleSolenoid slow or contaminated
Repair at a glance
- Difficulty
- Shop_only
- DIY friendly
- Best left to a mechanic
- Typical labour
- 3–12 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Cylinder Deactivation Solenoid, Lifter, Oil Control Valve
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.