Fault code P0229 – a step-by-step guide to diagnosing and fixing it

Error code P0229 is displayed and the check engine light is on - what does this mean?

The OBD/EOBD system has detected a fault in the turbocharger/compressor control circuit, which is stored as DTC P0229. This trouble code indicates a problem with the boost pressure control, whereby the boost pressure is outside the parameters specified by the control unit. For various manufacturers, this fault code can also be referred to as "Turbocharger/Supercharger Boost Control A Performance".

What causes can this fault code have?

• Defective boost pressure actuator (wastegate actuator)
• Damaged or leaking boost pressure lines
• Clogged or defective boost pressure sensor
• Faulty turbocharger geometry (VTG turbocharger)
• Defective vacuum pump or vacuum lines
• Dirty or blocked air filter
• Loose or corroded plug connections on the boost pressure system
• Defective engine control unit (ECU)
• Mechanical damage to the turbocharger
• Blocked exhaust gas recirculation channel (EGR)

What symptoms occur in parallel with fault code P0229?

• Loss of power: The vehicle shows significantly reduced engine power, especially when accelerating and under load.
• Black smoke: Black or blue smoke comes out of the exhaust, indicating incomplete combustion.
• Unsteady idling: The engine runs rough at idle or stutters noticeably.
• Starting problems: The vehicle is harder to start or requires several attempts to start.
• Increased fuel consumption: Fuel consumption increases noticeably because the engine is not working optimally.
• Whistling noises: Unusual whistling or hissing noises from the engine compartment, especially under load.

How can the problem with error code P0229 be rectified?

• Repairing EOBD code P0229 requires a systematic approach to identify the exact cause.
• Complete inspection and cleaning of the air filter: Replace the air filter and check the entire intake system for leaks or blockages, as a blocked filter can affect boost pressure control.
• Diagnosis and repair of the boost pressure actuator: Test the wastegate actuator for proper function using a diagnostic device and replace it if defective, including the associated vacuum lines.
• Turbocharger inspection and maintenance: Carry out a complete inspection of the turbocharger, check the vanes for wear or blockage and clean or replace defective components.
• Boost pressure sensor calibration: Check the boost pressure sensor with a multimeter for correct voltage values and replace it if it deviates from the target values.
• Repairing the boost pressure lines: Inspect all hoses and piping in the boost pressure system for cracks, leaks or loose connections and replace any damaged parts.
• EGR valve cleaning: Thoroughly clean or replace the exhaust gas recirculation valve, as blockages can negatively affect boost pressure control.