audimaniac2012

So having a small issue with my 2000 audi a4 1.8 quattro...

Seems as if anytime I start the car (even at a cold start) both my main fan and the ac fan come on instantly. Also, along with the ac fan coming on the ac compressor is also turning on.(cold ac lines) even though its about 40deg outside.

I am also throwing a cel for improper secondary air injection flow.
not sure if they are all related or seperate issues.

I read in the manual that the climate control can turn the ac compressor on automatically to adjust humidity inside the cabin, however i think something is malfunctioning because it is constantly running from start up until i turn the car on(unless economy button is engadged)


Are all 3 issues related?
should ac compressor always be running?
main fan always running?

Found a cracked hose for secondary air injection which I replaced and cleared cel only to have cel return a few days later for same code.

Thanks in advance for any help.

AudiMick

Are all 3 issues related? NO
should ac compressor always be running? Yes if ECON is not selected
main fan always running? YES It's mechanical

Does your car have an SAI pump, check it's working and that the rivets holding it together haven't failed. You can drill the rivets and permanently replace with nuts and bolts if the pump is still spinning.

GTA_Driver

A/C operation is normal. It always engages unless the ECON button is turned on.

The main fan is called a viscous clutch fan and it always spins with the engine, freewheeling. When the car gets hot it will spin faster, and you'll know it's on.

The only issue you have is the SAI pump/system.

audimaniac2012

Ok well thats great.. just seems kinda weird for the ac to always be running, wouldnt that shorten its life?

Havent checked the sai pump lately but will do so first thing in the morning..
Thanks every1

GTA_Driver

Au contraire, mon ami, having the compressor engaged more often will actually prolong its life. Also, it dries the air out to help defrost your windshield. Try one day to turn the ECON button ON when your windshield is fogged up. See what happens.

audimaniac2012

Would make perfect sense if it came on periodically or with defroster but constantly running seems odd to me..

Im not disagreeing with you, I believe you 100% just seems a little odd.

Im glad I dont have several issues, easiest fix ever lol

AudiMick

Most modern cars with auto climate control are like that. Using the AC lowers the dew point so the excess moisture in the air condenses out.

The only thing that stops it is when the outside temp is really low (look for the snowflake in the LCD display) it will not allow AC to run to prevent freezing of the system.

audimaniac2012

I was able to look at sai pump, it seems like its, fine.. I can hear it turn on and seems somewhat solid, I read somewhere that when they fail they sound awful is this true? If so I think mines still good.
I also read somewhere that its possible for the lines to clog up? Or maybe I have a bad check valve? What is the easiest way to diagnose this? Or do I need to just start pullin hoses off?

AudiMick

Make sure it's pulling a good vacuum, like I said earlier the rivets come loose and they spin but don't suck a lot of air.

Otherwise check the lines. The SAI is troublesome on our cars, there is a mod to remove it and not get a CEL. I can't find the link at the moment.

audimaniac2012

If I removed the system would I still pass emission test? Which btw is due next month lol