This bulletin applies to 2010-2014 GMC Savana and Sierra models equipped with the 6.6L Duramax diesel engine. The vehicle may experience a hard start, no-start, rough running and low fuel pressure and/or DTCs P0087, P0088, P0191 and P128E.
During inspection of the fuel system, contamination may be found. Shown here are examples of contamination.
The cure: clean and flush.