LynnBilodeau

My car is a 2004 SL55. 132,000 miles. Does not use oil. No smoke. No leaks. Still runs great.

Was doing some research on fixing the intermittent P0410 code.

I checked the fuse and the relay. they are both good. I can hear a noise on start up that I don't get any other time, so I am assuming (I know, dangerous) that the pump is OK.

Ran across this thread: https://mbworld.org/forums/e-class-w...de-solved.html

Here is a pic of the check valves referenced in that thread.




Pulled the front engine cover off mine and found two similar valves. Seems that would be the logical place for me to start.
I think I can remove the passenger side valve without issue, but not the bracket it mounts to unless I remove the RH upper supercharger housing.
On the left side, I can't even get the valve out without removing the supercharger housing.

I can get the housing gaskets, and they are not expensive. I can buy new or used check valves. What I haven't been able to find are the "U" shaped hoses that go on each.
Mine don't seem to be too brittle, and I guess there is a chance I can get them off and reinstalled without breaking, but would like to have a source.

I am pretty sure the valves are both working. I can put vac to each one; and with a finger on top of the valve, when I release the vac, I can feel and hear each one click. So I am hoping it is just a matter of cleaning things up.

Looks like the valves run about $125 per side.

Anyone done this procedure on an SL55 or other model with the same engine?

LynnBilodeau

I removed the valve on the passenger side and verified it was working fine. I put vac to the one on the driver side, and when I release the vac, you can hear the piston return, so I believe it also works. There was zero carbon build up. To be clear, there was black carbon inside as you would expect, but no build up; clear passage.

Now I am wondering if I the pump is simply inop.

LynnBilodeau

Took the pump off and bench tested it. Runs fine; nice and quiet and moves plenty of air.
Must be fuse or relay, right?

Lots of conflicting info. One says the relay is the "brown" one on the driver side. I have no brown one. See first pic. Is there a fifth relay missing? That would explain it.

Other source says the relay is relay N in this illustration of the passenger side relay box: file:///C:/Users/LJBIL_~1/AppData/Local/Temp/Relay%20assignment%20of%20fuse%20and%20relay%20box %20in%20right%20engine%20compartment.pdf

Is that the correct relay?

As for the 40 amp fuse. Exactly where is that fuse? I have also attached a pic of the passenger side fuse/relay box. I am missing at least two fuses; maybe a third, but the red circle to the far right show a fuse receptacle that appears to have no contacts in one of the female spade connectors.

The second red circled fuse receptacle is in a cluster of 5 amp fuses, so I would be surprised if it went there. The third (farthest to the left) looks like it could house one of the very large 40 amp fuses. Again, was that fuse removed by a PO?

Any help appreciated.
Lynn

LynnBilodeau

Found this: http://www.mercedesmedic.com/sl-class-r230-fuse-chart/

According to that chart, and these pictures file:///C:/Users/LJBIL_~1/AppData/Local/Temp/Fusemap_SL55_AMG.pdf
it looks like Fuse 31 on the passenger side (which I am missing) is for an "air pump" and relay "F" on the driver side (which I am also missing) is for a "pump".

Have a relay on the way, and will go pick up a fuse.

LynnBilodeau

Sure enough. Installed the missing fuse, found a spare relay that I had for my BMW, and it works fine. I have the correct relay on the way, and will swap it out when it gets here.

PeyotePaul

Did your code stay away after your fix?

Also, how did you end up removing the check valves to see if they were clogged?

LynnBilodeau

I ended up replacing the pump. Very easy to do once you get the RF wheel off, and remove the inner fender.

Apparently my old pump, even though it worked on the bench, would draw too much amperage from time to time, blowing the fuse.
Bought a pump on ebay for less than $100.

Code has not come back on since.
The passenger side valve is easily removed. Remove it first. If it isn't clogged, then my guess would be the other side is fine as well.

Good luck.

PeyotePaul

I took my car to the shop from some other repairs and they said the secondary air pump wasn't coming on at all. I'll be replacing the fuse, relay and pump soon as well. Was having some trouble location the fuse and relay but thank you for already identifying them

Ingenere

Does anyone know the part number for the relay?