punchpro68

Hey all,
I have an '02 S430 (W220) with 116K miles. This morning after driving for 10 minutes, my CEL came on. No malfunctions were displayed on the dashboard. There was one diagnostic code P0400 that was displayed when checked. From what I gather, it's related to the EGR valve.
#1) Where is it located on the car?
#2) Has anyone replaced (DIY) before? Any pictures?
#3) What else should I check that could cause the P0400 code?

Thank you in advance....

tusabes

EGR probably needs cleaning. Dont replace.

Jud Chapin

I would suggest purchasing the Benz STAR Service Manual Library DVD for your W220. It will show you how to r & r the valve along with most repair items on the car. This DVD is excellent. Call Benz @ 800 for-merc, p/n P-2700-220/215-07. It's under $100 shipped.

mbtechny

its located on the right side in back of the engine on the top. there is a pipe that goes into the valve its probably clogged. if you have and vacuum pump you can test the valve.i have seen the valves get stuck in which case i would replace it.

punchpro68

Thanks all for the direction. Found the EGR valve and began disassembling today. Before removing I tested it by pulling vacuum. Didn't start to move until about 6 "water vacuum pressure and then it popped open. Stroked the valve a few times but the opening vacuum pressure wasn't consistent (between 5 - 9 "water). Probably build-up on the valve. Though the engine did "stumble" whenevery I opened the valve so it's not 100% clogged. Also the vacuum pressure held steady so EGR valve diaphragm is not leaking.

punchpro68

When I finally got it out there was alot of carbon buildup in the valve and in the entrance on the engine block. Will clean everything out tomorrow & reassemble.

Jud Chapin

Keep us posted...

NAJLEPSI

pictures would be nice