P003A–P003B Turbocharger/Supercharger Boost Control A Position Exceeded Learning Limit
The value has run past the end of the range the ECU can work with, so it has stopped trying to compensate and logged the fault instead.
Can you drive it? The car is most likely in limp mode with boost cut. It is drivable gently, but it will not make full power and should not be driven hard until it is fixed.
Which code is which
Same fault, different cylinder or bank — diagnosed the same way. Several set together usually means one shared cause.
| Code | Definition | Severity |
|---|---|---|
P003A | Turbocharger/Supercharger Boost Control A Position Exceeded Learning Limit | Investigate soon |
P003B | Turbocharger/Supercharger Boost Control B Position Exceeded Learning Limit | Investigate soon |
The definition
P003A: Turbocharger/Supercharger Boost Control A Position Exceeded Learning Limit.
P003A is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.
What to check first
Cheapest and fastest checks first:
- Read the freeze-frame data stored with the fault - engine speed, load and temperature at the moment it logged tell you whether this happens cold, hot or under load.
- Check the connector at the part for corrosion, and that it is fully seated.
- Clear the code and see whether it returns, and under what conditions.
Reading the code is the easy part
A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.
VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.
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Prefer to work on your phone? The VAGPULSE Android app is a free download and its demo mode runs against a sample car with no hardware at all, so you can see exactly what it reads before spending anything. Reading your car with it needs the VAGPULSE cable, which comes with the licence.
Common questions
What does P003A mean?
P003A means Turbocharger/Supercharger Boost Control A Position Exceeded Learning Limit. The value has run past the end of the range the ECU can work with, so it has stopped trying to compensate and logged the fault instead.
Can I drive with P003A?
The car is most likely in limp mode with boost cut. It is drivable gently, but it will not make full power and should not be driven hard until it is fixed.