What it means
The position sensor signal for actuator B on bank 1 is below the lower diagnostic threshold. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
At a glance
- Usually lights the check-engine light
How it works
The B rocker arm actuator position sensor reports switching position on bank 1. This low-circuit code sets when its signal falls below the diagnostic threshold, often from a signal wire short to ground or a shorted sensor element.
Common causes
Most likely first.
- Internal short in sensor element
- Signal wire shorted to ground
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- Reduced engine power or acceleration
- Rough running or engine misfire
How to diagnose it
- Record freeze-frame data and check live B position-sensor data on bank 1 to confirm the signal is low while the fault is present.
- Inspect the sensor connector and harness on bank 1 for chafing, moisture, corrosion, or pushed-back pins.
- With the live signal displayed, gently move the harness to see whether the reading changes and help locate an intermittent short or poor connection.
- Test the signal wire for a short to ground and check the sensor element using the manufacturer's procedure.
- If the sensor and wiring pass, check the reference and module input circuits against the manufacturer's specification.
Common fixes
- Dry, clean, and secure the B sensor connector on bank 1.
- Repair chafed signal-wire insulation or a short to ground.
- Replace the B position sensor if its element is internally shorted.
- Repair a faulty reference or module-side connection identified by testing.
Can I keep driving?
Limit driving and avoid hard acceleration if power is reduced or the engine runs roughly, because the controller may not know bank 1 actuator B's position. Stop if severe misfiring develops or the check-engine light flashes.
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.