DEF is an Aldehyde free, NOx reducing treatment for diesel engines equipped with a selective
catalytic reduction (SCR) system. It can also be used with competitive make vehicles using a SCR
system. DEF meets the stringent AUS 32, ISO 22241 standards for purity and concentration.
This product is required for the 2010 mid-year launch of the Chevrolet Express and GMC Savannah
vans equipped with the new regular production option (rpo) LGH Duramax Diesel engine and the
2011 model year Chevrolet Silverado and GMC Sierra new heavy-duty pickup and chassis cab
models equipped with the new rpo LML or LGH Duramax Diesel engines. It is part of the SCR
technology used on these vehicles to meet 2010 EPA emission regulations.