P0505 and pending P0456... Vacuum leak?
 

Hey guys,

Had CEL come on for P0505 come up today and had P0456 as a pending code. Stock throttle body, 70k miles. Car is pretty much stock other than a pulley.

I took the air cleaner off and looked around for a vacuum leak but didn't find anything. Only thing that came to mind is the "hard line" that goes into the back of the supercharger that people say has a tendency to come loose. My only question is, how does that come loose?? There is a metal tab where it gets screwed into place, so i don't see how that could move/come loose. My car is a 2005 E55.

Any input/suggestions are greatly appreciated.

p0456
Canister, vent valve, sender unit(s), or gas tank neck.

Gas smell would lead you to the tank

My P0456 came from a vacuum leak from right behind the drivers head light. There is a pump with a black foam filter on it... my vacuum line had come loose fwiw

P0505

"metal hose that goes into the sc snout and the other end of it goes to a rubber hose on the fire wall by the fuel line. chances are that rubber hose is off"

https://mbworld.org/forums/w211-amg/...ode-fixed.html

Good luck!

Do you happen to have a photo of this metal hose that goes to the snout of the blower? Mine is held down by a metal tab so no way that it can come loose. On the other is a plastic tube thats held down by a hose clamp, which also has no chance of ever getting lose. I must be looking at the wrong thing...

http://www.benzworld.org/forums/r230...solutions.html

Pretty sure you need to remove surge tank to check the the connection that you cannot see going into the SC itself. If there is a code, there is a leak. You cannot go with the logic of "there is a clip it cannot leak" It is leaking you need to now find out where.

I would then check post metal hose to firewall connection as well. I am just using google fu to help:


https://www.google.com/search?rlz=1C...w211+e55&pws=0

I have found that tube, but mine doesnt run along the firewall like the photos im finding. Mine has a plastic hard line under the airbox, goes from the valve by the headlight, then turns toward the SC snout and goes in. This is definitely all stock parts, its all got MB and AMG stickers...

I'm going to remove it and reinstall it today, even though it has a hard metal tab holding the tube in place, bolted to the valve cover. I'll try it... not sure what else this may be.

Im thinking its a vacuum leak, no other ideas as to where to look...

check the hose on the side of the driver side connected near airbox that tends to blow off.

Agree on remove and reinstall, I would think aging or heat stressed rubber/plastic could have cracked and could be the cause

Could you run a temp line to eliminate the run as the issue? That may help you move on to other causes. Maybe use some hard "fuel injector" hose from the autoparts store and couple it up and see if the issue resolves? Just thinking outloud here I HATE CELs turned on

Are you referring to the purge line near the throttle body?

Check all those hoses

https://cimg7.ibsrv.net/gimg/www.mbw...49057afe13.jpg
https://cimg9.ibsrv.net/gimg/www.mbw...e3b0d23e31.jpg
I did a little home-brew testing/troubleshooting and i concluded that its not a vacuum leak i'm after. Let me know if you agree:

1. Removed air cleaner assembly
2. Sealed off the TB with saran wrap and the rubber ring. Hose clamp is a good idea here as i blew this right off the TB the first time i did steps 3 or 4 (if not a hose clamp, ask someone to hold it while you do the rest)
3. Remove the hose from the purge valve and blow into it while holding the large one shut with your thumb
4. In lieu of #3, blow into the large hose coming from driver's side valve cover and hold the purge hose shut with your thumb

I did the above and definitely didnt hear any leaking. It also built plenty of pressure, so much so that I couldn't blow any more. I did some vacuum leak simulations where id pull a hose off on the valve cover just a little bit, and when doing steps 3 or 4, i would clearly hear hissing.

My method may not be the most professional, but i do think that it helped me rule out a vacuum leak.

Now back to square one... Why did the codes pop up yesterday?

Purge valves have been known to temporarily stick in the open position at times and very intermittently. This would cause both of your fault codes and could explain why you can't find the cause right now.

I would love it if you were right. That's a real easy fix. I guess only time will tell... and i'll report back here with any updates.

FWIW my experience has been after every two engine cylces (off/on/drive/off) those codes will pop up out of pending.

Were you able to confirm that the hard line in the back of the S/C is fully seated within the grommet?

I did. I unbolted it from the valve cover, moved it around a bit and put it back in. I think that it was seated correctly the whole time. I did my little testing "procedure" from above and nothing came out of there, seemed pretty well seated and sealed.

When you say "pop out of pending", do you mean they become a real code and trigger the CEL or do they disappear?

OBD will record "pending" codes, which do not trigger a MIL/CEL for one or more warm-up cycles. This is (as best I gather) to reduce false positives in the event of a detected fault.

Found this searching for info:

P0505 - Possible causes:
1. Faulty IACV-AAC valve
2. IACV-AAC valve harness is open or shorted
3. IACV-AAC valve circuit poor electrical connection

IACV - idle air control valve
AAC - auxiliary air control

Does anyone know what these things are and where they might be located on the M113K? I definitely don't have a clue... :smash:

https://mbworld.org/forums/s55-amg-s...or-engine.html

hopefully that helps.

Where is the IACV-AAC valve located on the 113k engine?

IIRC, IACV is just behind the driver (US) headlight. Should have three vacuum lines and two-wire power plugging into it.

The AAC is the electric motor-driven fan, which is located in the lower half of the engine bay, behind the passenger light.

Feel free to correct me....

Is that right??? Idle air control valve is whats commonly known as the purge valve? Id really appreciate it if someone can confirm.

FYI Rob - given we are talking about the same thing, the purge valve (as i know it) has a hose in, hose out and a 2-wire connector.

no they are not the same thing. By the way we don't have these iacv-aac

I see... So what's the official name of the electronic device connected at the vacuum lines behind the driver's side?

purge valve

Cool. Thanks!

Anyone know the part number for the purge valve? I've got P0456 and I'm fairly certain the valve is stuck open causing the CEL. I've just been clearing the code but it doesn't seem like a hard part to replace.