What it means
The position sensor that confirms the A rocker arm switching state on bank 1 returns no usable signal. Closed-loop control of valve lift cannot verify the state.
At a glance
- Usually lights the check-engine light
How it works
The position sensor for rocker arm actuator A on bank 1 confirms whether the valve-lift switching mechanism reached the commanded state. P264A is set when the controller receives no usable position signal, preventing it from verifying that bank 1 changed valve mode.
Common causes
Most likely first.
- Open sensor element
- Corroded sensor connector
Symptoms
- Check-engine light
- Reduced engine power or acceleration
- Rough running or engine misfire
How to diagnose it
- Save freeze-frame data and check for related rocker actuator or misfire codes.
- Identify the bank 1 A position sensor from service information and inspect its connector and wiring for looseness, corrosion, or damage.
- Check the sensor supply, ground, and signal circuit according to the manufacturer's wiring diagram and test procedure.
- Use live data to see whether the bank 1 A position reading is absent or fixed while the actuator is commanded to move.
- If the circuits are intact, test the position sensor and actuator movement separately to determine whether the sensor has failed or the mechanism is not moving.
Common fixes
- Reconnect or clean the bank 1 A position sensor connector.
- Repair a damaged sensor supply, ground, or signal wire.
- Replace the bank 1 A position sensor if it produces no usable signal despite correct circuit supply and ground.
- Repair a sticking actuator mechanism if testing shows the position sensor works but the rocker system does not move.
Can I keep driving?
If the engine runs smoothly, limit driving to necessary short trips because the controller cannot verify bank 1 valve-lift state and power may be reduced. Stop if misfiring becomes severe or the warning 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.