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Took the ol bus into a stealership earlier this week to check via VAG com a managment light and came back as a possible fault in the Secondary air pump What the hell is that ??? Said it wasnt work and obviously thats initiating other codes to come up. Car is running sweet with no issues I can see elsewhere. Any one help with this and give me a sort of cost to replace as the stealership have quoted a price in italian lire I think

Thanks

Secondary air pump only kicks in on cold start up. It only reduces the emissions for about 2 minutes then stops, if I am not mistaken.

As suggested above it is designed to dilute the exhaust emissions on cold start-up. It pumps fresh air into the exhaust. If there is a restriction or a sec air system pipe off it will throw up a code, as its emission relaited it will put the ecu light on as well.

New pumps are a bit pricy so look around for a s/hand one. Ask the servicing dealer to check that the pump unit faulty rather then a open circut.

philipwalker wrote:As suggested above it is designed to dilute the exhaust emissions on cold start-up. It pumps fresh air into the exhaust. If there is a restriction or a sec air system pipe off it will throw up a code, as its emission relaited it will put the ecu light on as well.

New pumps are a bit pricy so look around for a s/hand one. Ask the servicing dealer to check that the pump unit faulty rather then a open circut.

thanks guys I thought as much and makes sense Doug mentioned it was abit noisey on its last health check

Is it an esential part or can I take it out and do without??

The pump is no use to you. S4s don't have it. It's just to fool the o2 sensor to meet later emission standards on warm-up. You don't need it.

So if you remove the pump, how do you stop the engine warning light coming on?

The secondary air system is used to warm the lambda probe and catalysts up as quickly as poss after a cold start.To do this it blows air into the exhaust system this does not dilute the exhaust gas but makes them hotter(a bit like turning on the oxygen supply of an acetaline torch makes the flame hotter)The car definately needs it to be working or it will keep throwing the eml on no way around it its part of the eu3 emission control of the ecu.Fault code is prob sec air low flow have fitted a few myself tend to go noisy then seize.

I had what I assume was the original item fail after about 70k. The replacement (new, from main dealer) failed about 6 months later, replaced under warranty. This has now failed again (or at least, I have the fault code again, just yesterday - spooky!). Is there anything that could be causing the failure I need to investigate before having another pump fitted?

Depending on what fault code you are getting check the fan function using final control on a vag com or similar,also check vac hose integrity to the secondary air valves on the back of the cylinder heads.tend to go brittle and split after time caused by the heat off the exhausts.

Thanks RSW. I will check, but last time (on the new pump) failure was total - pump presented itself as a short circuit and of course therefore wouldn't spin I'm really after any thoughts on what might cause that - just bad luck, or something else in the system at fault?

We remove th esecondary air injection from a lot of rs4s and 1.8ts and can disable the ecu checks for it.

why remove it?

why keep it? just another thing to go wrong and makes it easier working on the engines with it all removed.

cold start emmisions are not tested in this country.

Doug, if you can disable the MIL, sounds great. To me it seems like a noisy item when it is working, and an annoying one when it isn't!

Doug_S2 wrote:We remove th esecondary air injection from a lot of rs4s and 1.8ts and can disable the ecu checks for it.

Hi doug

do you remember her making the noise from the pump when she came up for brakes and a genric, service etc a few months back? Sounds as though its now failed according from the stealership. they want to charge some horrific price on a replacement and cant see the point if its not needed at all. Can it can be removed fairly easily? and if its not needed to be replaced for MOT etc. If so can you PM me and let me know if you'd do it for me, cost etc and perhaps lets slap on a milltek cat back at the same time !! Seems rude not while we're there Ill just tell her in doors the exaust as fallen off !

Cheers to all, quality info