What it means
Voltage on the rocker arm actuator B control line on bank 1 is below the expected window. Usually a short to ground or a shorted solenoid coil.
At a glance
- Usually lights the check-engine light
How it works
The B rocker arm actuator control circuit on bank 1 carries the controller’s command to the actuator that switches valve lift mode. This code sets when the circuit voltage is below its expected range, often because the control wire is shorted to ground or the actuator coil is internally shorted.
Common causes
Most likely first.
- Control wire shorted to ground
- Internal short in solenoid coil
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- Reduced engine power or acceleration
- Rough running or engine misfire
How to diagnose it
- Save freeze-frame data and check live data for the bank 1 B actuator command and whether the fault appears when the controller switches it.
- Inspect the B actuator connector and harness on bank 1 for a pinched control wire, corrosion, oil intrusion, or a short to ground.
- Check the actuator coil for a short and inspect connector pins for corrosion or poor contact.
- Test the control wire for a short to ground and check circuit continuity with the actuator disconnected, following the wiring diagram and manufacturer’s specification.
- If the harness passes, test the controller output and replace the B actuator if its coil is shorted.
Common fixes
- Repair a bank 1 B control wire shorted to ground.
- Clean or replace corroded actuator connector terminals.
- Repair damaged harness insulation near the bank 1 B actuator.
- Replace the bank 1 B actuator if its solenoid coil is internally shorted.
Can I keep driving?
If the vehicle remains smooth, keep driving limited and avoid heavy loads because the bank 1 B lift mode may not respond correctly. Stop if engine misfire or loss of power makes the vehicle difficult to control.
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.