Hi all , I dont think my secondary air pump is working as when i turn the car on for the first time i cant hear it pumping away for 30 seconds or so . It just sounds like a normal car on cold coke .

Now would this cause me to have no boost as my gauge is reading 0.3 bar untill i turn her of and back on again or could his be the N75 ?

If it is the secondary air pump causing this do you think taking it off would fix it ?

You need to see if you've got any codes. Wouldn't be surprised if you find the dreaded 17705 code.

There are a bunch of maps out there with an incorrect value in the software that throws 17705 on cold start up which puts the car into limp.

Edited 30 November, 201015 yr by pauldazzle

A fault in the secondary air pump system can throw 17705 too.

Here's a repair guide......................

http://uk-mkivs.net/forums/t/141240.aspx

i had a similar problem not too long ago. but the weird thing is i think it may be the ambient temperature that triggers the Secondary Air Pump.

I think in this cold weather they can be a little bit temperamental and another member on my last post stated that the pump only triggers when the coolant is between 5 and 30 degrees. not sure if this is right but if the coolant is colder than this, then could this cause the pump NOT to start?!

sorry not much help but could be the answer to your problem

If it's cold enough to scrape ice off the windscreen, mine never runs. It's actually quite pleasant not to have the wheezy sound and makes up for the freezing hands and bent Tesco's Club Card as I scrape merrily away..

i had a similar problem not too long ago. but the weird thing is i think it may be the ambient temperature that triggers the Secondary Air Pump.

I think in this cold weather they can be a little bit temperamental and another member on my last post stated that the pump only triggers when the coolant is between 5 and 30 degrees. not sure if this is right but if the coolant is colder than this, then could this cause the pump NOT to start?!

sorry not much help but could be the answer to your problem

Yeah I saw that post about 5 & 30 degrees, but it doesn't add up as the Secondary Air Pump is there to warm the CAT up quickly to aid low emissions. I've owned a bunch of VAG cars & the secondary air pump has always kicked in on cold starts below 5 degrees.

Hi all , I dont think my secondary air pump is working as when i turn the car on for the first time i cant hear it pumping away for 30 seconds or so . It just sounds like a normal car on cold coke .

Now would this cause me to have no boost as my gauge is reading 0.3 bar untill i turn her of and back on again or could his be the N75 ?

If it is the secondary air pump causing this do you think taking it off would fix it ?

The pump not working is correct if it's cold. I've said it before, and I'll say it again!

"Secondary air injection system

Operation:

Air is injected downstream of the exhaust valves by the secondary air system for up to 100 seconds after a cold start (+5�C�+33�C coolant temperature). This enriches the exhaust gas with oxygen, initiates a post-combustion and thus shortens the heating-up phase of the catalytic converter. Actuation is performed by the Motronic control unit �J220- through the secondary air pump relay �J299- to the secondary air injection valve �N112- (changeover valve) and combination valve. In addition, after each subsequent engine start (up to an engine temperature of max. 96�C), the secondary air system is switched on in the idle speed range for 10 seconds and checked by the self-diagnostics. The lambda control must be active for this purpose."

So if it's less than +5 degrees out, it will not run.

Your other issue with running 5 psi means your car is in limp mode. Expect a 17705 error code. Dirty throttle body or leaking breather/vacuum/pressure hose somewhere. Don't waste your money on a new N75 like everyone always does, just because it's something easy to change!

Yeah I saw that post about 5 & 30 degrees, but it doesn't add up as the Secondary Air Pump is there to warm the CAT up quickly to aid low emissions. I've owned a bunch of VAG cars & the secondary air pump has always kicked in on cold starts below 5 degrees.

Well it is true I'm afraid!

I've copy and pasted direct from the official Skoda workshop manual above.

My pump doesn't switch on below 5 degrees coolant temperature. That temperature range may be specific to the AUQ, so no point comparing to other cars.

Well it is true I'm afraid!

I've copy and pasted direct from the official Skoda workshop manual above.

My pump doesn't switch on below 5 degrees coolant temperature. That temperature range may be specific to the AUQ, so no point comparing to other cars.

Bodge, I acknowledge your great experience with these cars, but I can only go on my experience, that all of my 3 Golf mkiv's including an Anniversary (AUQ) & an Audi A3 Quattro have all been the same i.e Secondary air pump kicks in sub 5 degrees. My VRS is the same, we've been having sub 0 temps for the past week & my pump comes on for 90 secs or so every cold start.

Now if you're saying that the coolant temp has to be above 5 degrees & not the ambient temp then I get it.

Edited 1 December, 201015 yr by pauldazzle

maybe there is an easy answer to this.

bodges quote is obviously correct but paul your comments are also correct. remember the temperatue 5-30 degrees is the temp of the coolant in the car and not the outside temperature. therefore even it is say -5 outside temperature due to the coolant and antifreeze whatever you have in there it probably does not freeze as fast as water meaning that the temperature of the coolant in all the times you started the car in freezing temperatures must have been 5 degrees or above

Edited 1 December, 201015 yr by vrs200bhp

Yep, If I had read Bodge's post properly I would have relaised he was talking about coolant temp.

So guessing the pump is ok . I'll check the hoses when the weather clears up . Ive had the 17705 code before i cured it but she pulls like a train ! , I cant see it or hoping it hasnt come back . The person who re-maped it said he thinks the N75 may need changing just hasnt got round to it or found one cheap enough .

Forgot to say its like 2-3 times a week maybe its on 0.3 bar not all the time

Edited 1 December, 201015 yr by VRS Nick

I still think you may have an issue with the secondary air pump, & agree with Bodge that its very unlikely to be a problem with the N75. Get Vagcom on it & I bet you have 17705. :S

Edited 1 December, 201015 yr by pauldazzle