Usually means a bad Air Mass meter. There are real tests and adaptation numbers available with proper tools. That code means the ability to adapt has reached the end of range. There are two forms of adaptation involved and the first step would be to look at the numbers and see which is at the end of range. turns out that unless you have a vacuum leak or low fuel pressure, you most likely need an AMM.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician