What it means
The adaptive learning offset for camshaft profile actuator A position sensor B has reached its learning limit. Long-term mechanical wear of the cam profile lock pin or oil control valve.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Position sensor B monitors the position of camshaft profile actuator A for the engine control module. This code sets when the learned correction for that sensor reaches its limit, indicating that actuator movement or sensor B feedback is outside the range the module can adapt to.
Common causes
Most likely first.
- Camshaft profile actuator A position sensor B fault
- Actuator or position sensor wiring or connector fault
- Camshaft profile actuator sticking or worn
- Low or contaminated engine oil affecting actuator operation
Symptoms
- Check engine light on
- Power loss especially in mid-rpm range
- Possible rough idle or stalling
- Increased fuel consumption
How to diagnose it
- Save freeze-frame data and compare actuator A's commanded position with sensor B feedback to see under what conditions the learning limit is reached.
- Check engine oil level and condition because restricted or degraded oil can impair movement of profile actuator A.
- Inspect the sensor B connector and harness at actuator A for corrosion, loose pins, chafing, or oil contamination.
- Check sensor B's signal through the actuator's operating range and test its power, ground, and wiring against the manufacturer's specification.
- If sensor B and its circuit pass, inspect profile actuator A and its lock pin for slow movement, sticking, or wear.
Common fixes
- Top up or replace low or contaminated engine oil with the specified grade.
- Repair the sensor B harness or clean and secure its connector at actuator A.
- Replace position sensor B if its feedback is faulty during testing.
- Repair or replace camshaft profile actuator A or its lock pin if mechanical sticking or wear is confirmed.
Can I keep driving?
You may be able to drive gently if the engine remains stable, but avoid high load and monitor for rough idle or stalling. Continued incorrect profile control can reduce power and increase fuel consumption.
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.