What it means
The boost control module A reports that its calibration data is not present or not learned. Boost regulation falls back to default values until programming or adaptation completes.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Boost control module A manages turbocharger or supercharger boost using stored calibration data and learned settings. This code sets when module A lacks valid calibration, so boost control may use fallback settings and the vehicle may limit power or charging-related functions indicated by the supplied symptoms.
Common causes
Most likely first.
- Module replaced without programming
- Calibration memory corrupted after voltage drop
Symptoms
- Charge status indicator shows fault
- Charging may not start or interrupts
- Slower-than-expected charge rate
How to diagnose it
- Record freeze-frame data and scan all related modules for low-voltage, communication, or programming codes that appeared with the calibration fault.
- Check the repair history to determine whether boost control module A was replaced or the vehicle recently experienced a battery or voltage interruption.
- Inspect module A's power, ground, and connectors for loose connections or damage that could interrupt calibration memory or communication.
- Use a compatible scan tool to check module A's calibration status and compare its identification and software state with vehicle records.
- If the calibration is absent or invalid, perform the manufacturer's specified programming or relearn procedure, then verify the code does not return.
Common fixes
- Restore stable battery voltage and repair any faulty module power or ground connection.
- Program or relearn boost control module A using the manufacturer's procedure.
- Replace module A only if its calibration cannot be retained after correct programming and circuit checks.
Can I keep driving?
With reduced power or interrupted charging, avoid heavy loads, steep climbs, and long trips until module A is correctly calibrated. If the vehicle cannot maintain safe speed or charging, stop somewhere safe and arrange service.
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.