I'm having the code P0400 on my 1999 E300D. I have solid vacuum from the EGR valve when using my vacuum pump. I exchanged 2 EGR solenoids with no joy. I WAS having the wastegate code, but not lately. I applied power to the EGR solenoid with "+" to the red wire and gray wire "-". I do NOT get a "click" on any of my solenoids. Should there be a click when applying power? When I had the wastegate code several months ago, I checked the vacuum from the EGR solenoid to the wastegate;it was solid. Side notes: It takes about 5 miles for the CEL to return after erasing the code. The car runs perfectly with lots of power with light on at 201,000.

I'm at a lost besides maybe the valve itself needs cleaning. Could the K40 be the problem? Everything works perfectly in the car except I GET the 400 code.

Thanks for any help!

Richard

A failing K40 will result in weird, seemingly unrelated symptoms. If yours is original, I would go ahead and replace it.

__________________
14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 160k miles
06 E320 CDI "Rutherford", Black on Tan, 180k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 79k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

I don't remember the numbers. What is the description on that code? Is it a boost related code? If it is first place to look is the hose on the drivers side of the intake that goes to a sensor on the divider piece in front of the brake fluid reservoir (engine side). If hose is connected remove it and make sure the nipple that it fits on is clear.

__________________
Jim