I have sprinter with OM-651 (2010 model) with 185K miles, The DPF is NOT blocked, the soot load is reported at less than 10%. I managed to get set up the torque app so I could monitor some parameters. This is what happens when a regen starts on my vehicle: 1. the cat temp climbs to 700 degrees, (more fuel injected later?) 2. the throttle closes to 10% what does the throttle do in diesel engine? or is the something do with the EGR? 3. Boost is much lower, it goes negative when the engine is on the overrun. If a push a little to hard on the accelerator, the regen stops with a boost pressure fault, the boost pressure is not that high maybe 10 or 15 psi. If a stay in a higher gear the regen will complete, and the vehicle carries on light a freight train and pulls just under 23 psi of boot with pedal all the way down. My question is what is supposed to happen? and any ideas on the likely fault?