My wife's check engine light came on and it appears the secondary air pump isn't working. I checked the 40 amp fuse and it was still ok. I tried to run the pump by hooking power directly to it and no-go. Appears the pump is bad. Can these be rebuilt or best to buy new (or used). Any part numbers to use in the search of a replacement unit/does this pump cross over to Mercedes or something else?

I'll check the relay next to see if it's ok or the points need to be cleaned up, but in any case, I need a new pump.

Where is the best place to buy one? Prices range greatly and thought someone may know of a great place, thanks

 

These can be rebuilt if you are a bit handy, not too easy but worth it if you can do it yourself. It has to be a repairable fault not burnt out coils or something.

Read this and see if yours is repairable. CLICK

The pump should have the Mercedes part number on it.

 

Thanks for the information. Will take a look soon.

 

Has anyone tried to trick the computer somehow and not actually repaired or replaced the faulty secondary smog/air pump? Was thinking there may be a vacuum line that senses when the pump comes on at start up and if it could be supplied a vacuum by some other means, it trick the computer into thinking all is well with this pump.

Just a pain and costly to fix this useless pump and was wondering if anyone has every developed a work-around for not having the pump.

 

I read about how it determines the pump is running, back two years ago when mine acted up. I BELIEVE I read that the PTCM watches the O2 level in the exhaust, then commands the pump to run - if it does not see an increase in O2, it sets a "low/no flow" code. So, no, you are not going to re-map the PTCM's code for THAT, are you? I mean, not for less than 'way too much money', a pump would be cheaper.

You can google the P0401 code and read about it, that's how I found the description of what it was doing.

 

Thanks for the input. Seems you already know. My pump isn't working and the state inspection sticker is coming up soon. I was wondering if I can remove the pump and mess with it and my wife still be able to drive her car. Would you know that?

Just think while at work and not looking at the car. Will check the relays as well to see if one is burnt....

 

Running the car without it would be fine, IF the check valve that prevents exhuast flow thru that port(s) is not part of the assembly you remove. I just can't picture it all in my head, but I THINK the check valve(s) (I think there are two) are not part of the assembly, so you'd be ok.

I just can't say for sure.

 

Finally got around to messing with the air pump. Electric motor in the pump is burnt up. So I need a new pump. Any pointers on where to get one that doesn't cost so damn much? Anyone have a used one for sale?

thanks

 

Try Car-Part.com--Used Auto Parts Market

I see them there from $50 to $350 and a bunch of "call for price" under Crossfire.
Under Mercedes SLK320 I see them as low as $10

 

Did some research on used ones and found many places on ebay - got a nice one for $39. On way in mail

 

Good deal.
Best to send the RCM to tighed1 and have the air pump relay replaced as soon as you can.

BTW, that is a poor design by MB, a 40 amp rated relay with a 40 amp fuse driving a 40 amp motor.
That relay should be at least a 60 amp, if not an 80 or 100 amp relay.

I once researched and designed how to insert a larger relay in the wiring external to the RCM, but never carried through with it, although I did acquire a few 100 amp relays for the job.
( the 100 amp relay is too big to fit inside the RCM enclosure )

 

Appears all that is wrong was the motor fried. The 40 amp fuse was still ok, I pulled the RCM tray and all of them look like new. No discoloration at all and all the point gaps are perfect. Going to just install the air pump and see what happens

 

OK, but the normal cause of a fried air pump motor is a stuck relay.
Those motors get real hot real fast if the relay contacts stick.

 

What physical damage do you see?

 

see pics of burnt air pump motor

 

Reminds me of what was on my plate at breakfast this morning - toast.

 

Your lucky it wasn't an srt6 air pump that fried. Finding them used is next to impossible.

 

Gents, I am the Mercedes product manager at FCP Euro. If you need new SLK parts for your crossfire's feel free to pm me or email kyle@fcpeuro.com

I'll always happy to help and have helped out a few members in the past.

--Kyle

 

Awesome! Glad your here to help us MB drivetrain folks!




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Thank you Kyle, if it were not for the symbiotic relationship with Mercedes I'm afraid our unique automobiles would slip Into Obscurity mainly because of the eventual lack of available parts. Outer skin parts are already so scarce that they are expensive and insurance companies are writing these cars off as totaled with relatively minor damage just to get rid of them. Once again thanks for taking an interest.