Smart Forfour Turbo Failure: Whistling & Power Loss Warning

Faced similar symptoms on a Smart ForTwo CDI 2008 with the turbocharger system. The actuator fault triggered identical issues, power loss, rough idle, and boost pressure problems. The turbo actuator was indeed the root cause. The actuator valve had developed internal wear, preventing proper boost control. The electronic bypass valve was not responding correctly to ECU signals, causing inconsistent boost pressure. During diagnosis, a vacuum test revealed the wastegate wasnt maintaining proper pressure. The actuator fault was confirmed through diagnostic scanning, showing erratic boost readings. The repair required a complete turbo actuator replacement since individual components cannot be serviced. The job involves removing the turbocharger assembly to access the actuator valve. Its a serious issue that will worsen if left unattended, potentially leading to complete turbocharger failure. Key indicators pointing to actuator problems: Boost pressure fluctuation, Whistling under acceleration, Check engine light with boost-related codes, Increased fuel consumption, Power delivery issues Recommend getting it diagnosed soon, as continued driving with faulty boost control can damage other engine components.

Thanks for sharing your experience with the turbo actuator replacement. You described the exact symptoms I am seeing with my boost pressure issues. The vacuum test showing wastegate problems matches what I suspect with mine. Did you remember roughly what the repair ended up costing? Also curious if youve had any other turbo system problems since getting the actuator fixed. My pressure sensor readings are all over the place too, so I want to make sure I address everything while its being worked on.

I got the turbo actuator fault fixed last week, and it solved all the boost pressure issues completely. The repair came to 250€ for replacing the electrical bypass valve that was causing the erratic pressure readings. Since the repair, the turbo system has been working flawlessly, no more whistling sounds, stable boost pressure, and the engine runs smooth again. The actuator valve is now responding properly to the ECU signals, and fuel consumption has returned to normal. Make sure your mechanic checks the entire boost control system while doing the work. In my case, the turbo wastegate was actually functioning correctly, the boost leak was solely due to the faulty actuator. The pressure sensor readings stabilized once the new bypass valve was installed. Getting it fixed promptly was definitely worth it to prevent any potential damage to the turbocharger or other engine components. The investment saved me from more expensive repairs down the line.

I finally got the turbo system repaired last month and wanted to share the outcome. The mechanic found multiple issues causing my boost leak problems. The actuator valve had completely failed and the wastegate wasnt sealing properly. The total repair came to 780€ which included replacing the turbo actuator, fixing the wastegate mechanism, and installing new vacuum lines. More than expected but less than a complete turbocharger replacement. After the repair, the boost pressure stabilized immediately. No more whistling noises or rough idle. Fuel consumption dropped back to normal levels and the engine power returned to what it should be. The check engine light cleared and hasnt come back. Really glad I got it fixed when I did. The mechanic showed me the worn actuator parts and explained how close the turbocharger was to major failure. The whole boost control system works perfectly now, definitely worth the investment to prevent bigger problems.