Supposedly, the engine controls in my VW diesel (90HP 4-cylinder "TDI" engine) cut off all fuel when the driver was engine breaking (no throttle, RPM's above cu

Supposedly, the engine controls in my VW diesel (90HP 4-cylinder "TDI" engine) cut off all fuel when the driver was engine breaking (no throttle, RPM's above current desired idle speed). Perhaps they made other adjustments. It could brake pretty hard that way. I'd guess the engine controls in your Mercedes handled that situation rather differently, for "Mercedes customers will expect..." reasons.