wernercrystal82
XC40 Knocking Combustion Issue
Summary of the thread
A 2016 Volvo XC40 is experiencing knocking combustion, reduced power, jerking during acceleration, and smoke, with an error stored in the memory. The issue is suspected to be caused by excessive deposits in the combustion chamber. Suggested solutions include using a fuel system cleaner and checking the knock sensor. Ultimately, a professional diagnosis confirmed the deposits, leading to a repair involving thorough cleaning.
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4 comment(s)
wernercrystal82 (community.author)
I haven't tried a fuel system cleaner yet. How can I effectively test the knock sensor to see if it needs replacing?
laurathunder62
Testing knock sensors can be tricky without the right tools. Based on the symptoms, especially the smoke, and the error codes, it's probably more than just a sensor. Deposits in the combustion chamber seem likely. I'd advise a workshop visit for a proper diagnosis to prevent further damage.
wernercrystal82 (community.author)
I consulted a mechanic, and the diagnosis confirmed excessive deposits in the combustion chamber, causing the knocking. The repair, including a thorough cleaning, cost 425€. Thanks for pointing me towards a professional assessment.
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VOLVO
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XC40
laurathunder62
That sounds rough. I had similar issues before. Have you tried a fuel system cleaner? Also, when did you last check your knock sensor? A faulty one could be feeding bad info to the ECU.