Now I am confused...
From the BP website:
Controlled Lubricity ensuring it does not drop lower than 3100 grams, on the SLBOCLE (Scuffing Load Ball on Cylinder Lubricity Evaluator) test, which is the level required by engine manufacturers in their engine warranties. As sulfur is a natural lubricant its removal can have adverse effects on engine performance. BP uses a specially formulated lubricity additive to ensure the lubricity level remains higher than 3100 grams.
From Chevron's website:
Lubricity enhancing compounds are naturally present in diesel fuel derived from petroleum crude by distillation. They can be altered or changed by hydrotreating, the process used to reduce sulfur and aromatic contents. However, lowering sulfur or aromatics, per se, does not necessarily lower fuel lubricity.
The use of fuels with poor lubricity can increase fuel pump and injector wear and, at the extreme, cause catastrophic failure. Such failures occurred in Sweden in 1991, when two classes of "city" diesel with very low sulfur and aromatics contents were mandated. Heavy hydrotreating was necessary to make these fuels. The problem was solved by treating the fuel with a lubricity additive.
Many users were concerned when the U.S. Environmental Protection Agency (EPA) mandated on-road low sulfur (0.05% mass, maximum) diesel fuel and when California Air Resources Board (CARB) mandated low aromatics (10% volume, maximum) diesel. But there is no documented evidence that the use of these fuels, as a class, has led to increased wear, much less catastrophic failures.
They can't both be right.