What it means
The rocker arm actuator B on bank 1 stays in the activated state when commanded off. Engine cannot return to the alternate lift or cylinder mode.
At a glance
- Usually lights the check-engine light
How it works
The B rocker arm actuator on bank 1 controls the alternate valve lift mode. This code sets when the controller commands actuator B off but the mechanism remains activated, potentially because its lock pin or oil control valve is stuck and cannot release.
Common causes
Most likely first.
- Mechanical lock pin stuck in activated position
- Oil control valve spool stuck open
- Carbon or debris buildup preventing free movement
Symptoms
- Check-engine light
- Reduced engine power or acceleration
- Rough running or engine misfire
How to diagnose it
- Review freeze-frame and live data to confirm the bank 1 B actuator is commanded off while its position or mode remains active.
- Check engine oil level and condition, then inspect the bank 1 B actuator and oil control valve area for contamination or damage.
- Inspect the B actuator connector and wiring for a control fault that could keep the actuator energized.
- Use a scan tool to switch the bank 1 B actuator on and off while watching available position or mode data for a failure to return.
- If the electrical command is correct, inspect the oil control valve spool, lock pin, and rocker mechanism for sticking or debris using the manufacturer’s procedure.
Common fixes
- Repair a wiring or connector fault that keeps the bank 1 B actuator commanded on.
- Replace or clean a sticking bank 1 B oil control valve if confirmed by testing.
- Remove contamination that prevents the bank 1 B lock pin from releasing, where the manufacturer’s procedure permits.
- Repair or replace the bank 1 B rocker mechanism if its lock pin remains stuck in the activated position.
Can I keep driving?
Limit driving and avoid high-speed or heavy-load use because the bank 1 B mechanism may remain in the wrong lift mode, affecting power and smooth running. Stop if the engine misfires severely or develops abnormal mechanical noise.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.