What it means
The position sensor signal is below the lower diagnostic threshold. Usually a shorted sensor or short to ground in the harness.
At a glance
- Usually lights the check-engine light
How it works
The rocker arm actuator position sensor on bank 1 reports the position of the valve lift mechanism. The controller sets this code when the sensor signal falls below its lower limit, which can indicate a sensor short or a signal wire pulled to ground.
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
- Save freeze-frame data and check live data for a bank 1 position reading stuck low, then note whether it changes when the lift mode is commanded.
- Inspect the bank 1 sensor connector and harness for a pinched signal wire, corrosion, oil contamination, or a short to ground.
- Check connector seating and pin condition; high contact resistance or damaged terminals can disrupt the sensor circuit.
- Following the wiring diagram, test the sensor reference, ground, and signal circuit for shorts and continuity against the manufacturer’s specification.
- If the wiring is sound, test the bank 1 sensor output during actuator movement and replace the sensor if its signal remains below specification.
Common fixes
- Reconnect and secure the bank 1 position sensor connector.
- Repair a bank 1 signal wire shorted to ground or damaged harness insulation.
- Clean or replace corroded connector terminals and restore proper pin contact.
- Replace the bank 1 rocker arm actuator position sensor if it is internally shorted.
Can I keep driving?
A short trip may be possible if the engine runs smoothly, but reduced power or rough running can make acceleration unpredictable. Avoid heavy loads and stop driving if it misfires or loses power.
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.