I have a P0400 Code on a 96 e320, I understand this could be
a bad EGR or a blockage in the tubing.

Would some one clarify the following, When does the System activate Vacuum to the EGR? How does the system detect the EGR system is functioning correctly? If the O2 Sensors are involved, how will they effect the other systems?

EGR is(can be )active when: engine is in closed loop, not at idle, not WOT. ie; light cruise.

The DM uses info from the manifold MAP sensor to determine vacuum changes in the intake. The DM tells the HFM fuel computer to activate the test durning deceleration 1900-2600RPM.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Can anybody explain how to disconnect the tube which gets clogged up. Hopefully someone can show details with pictures which will help me alot. Thanks. I got that P0400 code and it seems that its common . I've got 112,000 miles. Thanks!

__________________
1996 E320- 18" Chrome AMG, Bling Bling Mirrors

I know there's something in the archives on this - with pictures. Sorry I can't be more help with where it is - but I think if you did a search on EGR pipe or EGR tube you'd find some things.

Add the word 'drill' to your search.

__________________
dtf
1994 E320 Wagon (Died @ 308,669 miles)
1995 E300 Diesel (228,000)
1999 E300 Turbodiesel ( died @ 255,000)
2006 Toyota Tundra SR5 AC 4X4 (115,000 miles) rusted frame - sold to chop shop
2011 Audi A4 Avant (165,000 miles) Seized engine - donated to Salvation Army
BMW 330 xi 6 speed manual (175,034 miles)
2014 E350 4Matic Wagon 128,000 miles
2018 Dodge Ram 21,000 miles