P1557 Charge Pressure Control - Positive Deviation (Overboost)
The turbo is producing more boost than the ECU asked for, which the ECU treats as dangerous and will cut power to stop.
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.
The definition
P1557: Charge Pressure Control - Positive Deviation (Overboost).
P1557 is a manufacturer-specific powertrain code (the engine or gearbox). Its meaning is set by the carmaker rather than by the SAE standard, so a generic OBD-II reader will often show it as an unknown code or misread it.
What to check first
Cheapest and fastest checks first:
- Check the wastegate actuator and its vacuum line - a disconnected line lets boost run away.
- Check for a sticking N75 solenoid or its wiring.
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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Common questions
What does P1557 mean?
P1557 means Charge Pressure Control - Positive Deviation (Overboost). The turbo is producing more boost than the ECU asked for, which the ECU treats as dangerous and will cut power to stop.
Can I drive with P1557?
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.