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Seeking advice for diesel Passat VW 2012: Black smoke, loss of power and engine indicator light active

Hi everyone, I need your help. My 2012 VW diesel Passat is behaving strangely. It emits black smoke when accelerating, the check engine light is on, there is a loss of power and the engine runs rough. It also jerks and hisses loudly when accelerating and shakes when idling. Maybe it was also a whistle? I thought it might be due to a malfunction in the boost pressure system. Have any of you had similar experiences or any tips as to what it could be? I would be particularly interested to know how you have solved this problem in your workshop and what your experiences have been. Many thanks in advance for your help!

(Translated from German)

17 comment(s)

Quotation:
@BAJAJA wrote on
I don't have any warning lights on and the engine works fine, but black smoke appears at the start of acceleration;

Black smoke at the start of acceleration usually indicates a rich fuel mixture, meaning your engine might be getting more fuel than it needs. This could be due to a faulty fuel injector, a clogged air filter, or a malfunctioning mass air flow sensor. Start by checking your air filter and replace it if it's dirty. If the problem persists, you may need to have a mechanic inspect the fuel system. Please keep us updated on your progress.

Hello, I have a problem with my Q5 built in 2013. It sporadically shuts down when I drive over 100 kmh. It is not the DPF. This has been checked. What could be the cause? After the emergency run, it indicated that something was wrong with the ABS or the tire pressure sensors. It also indicates that the turbocharger boost pressure is too low. Thank you in advance.

(Translated from German)

Quotation:
@Robin2402 wrote on
Hello, I have a problem with my Q5 built in 2013. It sporadically shuts down when I drive over 100 kmh. It is not the DPF. This has been checked. What could be the cause? After the emergency run, it indicated that something was wrong with the ABS or the tire pressure sensors. It also indicates that the turbocharger boost pressure is too low. Thank you in advance.

A sudden shutdown at high speeds can be concerning and potentially dangerous. Since the DPF has been ruled out, and given the error messages, I recommend checking the turbocharger system for leaks or blockages, as low boost pressure could cause the engine to shut down. Additionally, inspect the ABS and tire pressure sensor connections, as electrical issues could be affecting multiple systems. It's crucial to address this issue promptly, so I advise having a professional mechanic perform a thorough diagnostic. Please let us know how it goes or if you have further questions.

P029900

Quotation:
@Ramith wrote on
P029900

The P0299 code indicates that your engine is experiencing an underboost condition, meaning the turbocharger or supercharger is not providing the expected boost pressure. Start by checking for any visible leaks or damage in the turbocharger hoses and connections, as these are common causes. If everything looks intact, it might be necessary to have a mechanic inspect the turbocharger system more thoroughly. Please update us on your findings or if you need further assistance.

The car always sporadically goes into emergency mode when driving over 80 kmh or at operating temperature in the high speed range and over 80 kmh. The turbocharger has been replaced. Differential pressure sensor also. Hoses are apparently all tight. Water pump and oil pump have been replaced. What else could it be?

(Translated from German)

Quotation:
@Robin2402 wrote on
The car always sporadically goes into emergency mode when driving over 80 kmh or at operating temperature in the high speed range and over 80 kmh. The turbocharger has been replaced. Differential pressure sensor also. Hoses are apparently all tight. Water pump and oil pump have been replaced. What else could it be?

Since the turbocharger and related components have been replaced and checked, consider inspecting the intercooler for blockages or leaks, as it plays a crucial role in maintaining proper boost pressure. Additionally, ensure that the wastegate and its actuator are functioning correctly, as a malfunction here could cause underboost conditions. If these components are in good condition, a detailed diagnostic by a professional might be necessary to pinpoint the issue. Please keep us updated on your progress or if you have further questions.

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