Fault code P0039 – a step-by-step guide to diagnosing and fixing it

Error code P0039 is displayed and the check engine light is on - what does this mean?

DTC P0039 is triggered by the OBD/EOBD system when a problem is detected with the boost control valve (turbo boost control solenoid). This fault code indicates a malfunction in the range circuit of the boost control valve, which is responsible for controlling the turbocharger pressure. This code may have slightly different names for different manufacturers, but always refers to the boost control system.

What causes can this error code have?

• Defective boost pressure control valve (wastegate valve)
• Damaged or corroded cable connections to the solenoid valve
• Loose or defective plug connections in the boost control system
• Blocked or leaking vacuum lines
• Defective boost pressure sensor
• Faulty engine control unit (ECU)
• Mechanical problems with the turbocharger
• Defective wastegate actuation

What symptoms occur in parallel with fault code P0039?

• Loss of power: Significantly reduced engine power, especially at higher engine speeds
• Poor acceleration: The vehicle accelerates sluggishly or jerks when accelerating
• Irregular idling: Engine runs unevenly or stutters when idling
• Increased fuel consumption: Noticeably higher consumption due to inefficient combustion
• Black smoke: Dark exhaust fumes from the exhaust, especially at full load
• Whistling noises: Unusual noises from the turbocharger or vacuum lines

How to fix the problem of trouble code P0039?

• Correcting trouble code P0039 requires a systematic diagnosis of the turbocharger components.
• Replace the boost control valve: Replace the defective boost control solenoid with a new original spare part and check electrical connections
• Repair wiring: Locate damaged cables to the solenoid valve, connect severed wires and remove corrosion from the contacts
• Replace vacuum lines: Check all vacuum lines to the wastegate and boost pressure control valve for cracks and replace defective hoses
• Replace the boost pressure sensor: Replace the MAP sensor or boost pressure sensor if it is giving faulty readings
• Perform turbocharger service: Check mechanical components of the turbocharger, clean wastegate actuation and overhaul the complete turbocharger if necessary
• ECU reset and reprogramming: Reset the control unit after repairs and install software updates if necessary