That code doesn't mean that anything is wrong with the car most times! What it does mean is that the engine timing is being retarded to the MAX amount, about 12deg! POOR quality fuel is the most common problem even if you are "paying for" preminum 91 octane fuel! Carbon build-up in the engine can also cause this problem.

For 50+ years MB NEVER recommended any fuel additives but they do now suggest THEIR additive MB number 000-989-25-45-12. However I would try Tectron or another "aftermarket" cleaner.

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