The manual is indispensable for these notorious W639 tasks:
Skipping steps is the number one cause of customer complaints. If the manual says "Remove battery negative terminal" or "Drain coolant," do it. If it says "Remove front bumper to access headlight," believe it. w639 workshop manual
You cannot force a regeneration without the correct service manual steps. The workshop manual details: The manual is indispensable for these notorious W639