P0047Turbocharger/Supercharger Boost Control A Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- "Boost control A" is the electrically driven actuator the engine control module uses to set boost pressure: depending on the engine a pulse-width modulated solenoid or vacuum converter at the wastegate, the control valve of variable turbine vanes, or an electric actuator with position feedback. The letters A and B denote two separate actuators, for example on the low- and high-pressure turbocharger of a two-stage system, not the cylinder banks. This code is set when the voltage at the control output is too low, typically because of a short to ground; some manufacturers also report a missing supply this way. Without control the actuator usually falls back to its rest position, which on most engines means low boost; depending on the design too much boost is also possible.
- What you may notice
- Check engine light on
- Loss of power or reduced power mode
- Weak acceleration, noticeable turbo lag
- Overboost possible in rare cases
- Likely causes
- LikelyHarness chafed, short to ground
- PossibleActuator coil shorted
- PossibleWater in the connector
- RareOutput driver in the engine control module faulty
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €50 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.