secondary air injection pump runs every 5-10 minutes.

audi_guy · Dec 7, 2005

Hi all,

I've got a problem with my 2000 A4 1.8t ATW. With in the last couple of days the secondary air injection pump will start running for a minute or so then stop for 5-10 minutes then start running again. The happens for several hours even when the engine isn't running.

I used my VAG-COM to check for codes and readiness tests. There were no codes for any system and all readiness tests passed including all emissions tests.

Any ideas as to what is happening and what next to check to solve this problem?

Thanks

BTW: I also posted this in the VAG forum at AudiWorld.

moribundman · Dec 7, 2005

Auto Under Demonic Influence. Sounds like an electronic gremlin. Luckily my 2.8 Audi engine doesn't have that hairdryer. Sorry, I'm no help! Hope the guys at AW can help you.

wavinwayne · Dec 7, 2005

Check the Secondary Air Injection (AIR) pump relay -J299-. If the relay's terminals get even a little corroded, it can cause this problem.

If you need help locating it, let me know & I'll try to help.

ww

Mud · Dec 7, 2005

Also having troubles with daughter's 02 A4 throwing a code - P0411 I think, secondary air flow not right (my words!). I checked everything that I could and could not find a thing. She's taking it in to the dealer for a look first before anything is done.

I dread the estimate ......

eljefino · Dec 7, 2005

I don't think an oxygen sensor would have anything to do with an air pump running when the engine is off.

I also find it odd that a sticky relay would cause something to intermittently cycle on and off... A car not running should not input that behavior... An odd computer glitch seems more likely to me. But I defer to the euro experts on that...

wavinwayne · Dec 7, 2005

Mud,

Please post whatever the fix happens to be for your daughter's A4. We VW/Audi folks are haunted by the P0411 code, & nobody ever seems to be able to track it down.

My '00 VW GTI has this code right now, CEL included.

audi_guy · Dec 8, 2005

I found the problem. First off the wife called me at work and said the car was dead- no lights, no instrument led displays when opening the door, no nothing. That little Dust Devil Vacuum Clear Noise Maker had drained the battery deader than a door nail!

After unsuccessfully looking for the J299 secondary air injection relay, it's definitely not where my Bentley manual says it is supposed to be, I started looking at other things. I discovered a cracked vacuum/pressure hose near the coolant temperature sensor that I had changed a couple days ago. It is impossible to change the senor without moving that hose so I inadvertently cracked that it. Those hoses are covered in cloth braid so it's impossible to see if they are good or not.

Ok back to the Bentley manual to see what that hose went to. Well it turns out that it runs from the Combination valve for the secondary air injector pump, aka Dust Devil Vac, and the Secondary Air Injection solenoid valve. So the pressure would drop in that hose and trigger the solenoid valve which I assume turned on the Dust Devil Vac. This cycle kept on until the battery was drained.

I went to Advance Auto, AZ is on the the other side of town and I've already cleaned it out of GC Green

, and bought some vacuum hose for $1.46. Replaced the hose, used a couple zip ties, charged the battery, and we're back in business. So far after 2 hours, no Dust Devil Vac sounds.

audi_guy · Dec 8, 2005

quote:

2.8 Audi engine doesn't have that hairdryer.

moribundman,

It sounds just like a Dust Devil Handheld Vac.

quote:

pump relay -J299-. If the relay's terminals get even a little corroded

wavinwayne,

I'll check that tonight. I've got a Bentley manual . I should be able to locate it. If not, I'll send you a message. I've got a very good contact cleaner/protectant I used for driver's air bag connection resistance too high problem. So it should work fine on the relay connectors.

Thanks Guys...

Kestas · Dec 8, 2005

I'm having a similar problem with my Mercedes, which I believe is related to a bad oxygen sensor.

audi_guy · Dec 8, 2005

wavinwayne,

I found a german pdf for the a4 1.8t via google - couldn't wait until I got home.

It looks like J299 is located in the ECU box in the right back corner (from the driver's perspective). That sound correct to you?

Mud · Dec 9, 2005

WW, looks like we are also back in business after a trip to the dealership today. Gotta say they treated us well, very courteous and called me twice, once to let me know what a diagnosis cost before they touched it and again to tell me what the problem was. Car was in and out within a couple of hours. Total cost was $150 for diagnosis and repair and with shop rates what they are, it could have been worse. I was anticipating big troubles with pumps, solenoid valve, etc.

Despite my checking everything that I could, the problem was a cracked vacuum line. I don't have the car here but I will find out exactly which one it was. I had looked from above and below - had to take the belly pan off - but evidently it may have been similar to what Audiguy was describing as far as being covered with cloth. I won't know for sure till I get daughter/car back over here.

I can't say that it was the same line as what AG had described, but one additional symptom the car had was that (besides the CEL) it was pretty noisy while driving. Sounded like loud tire noise, but it happened after the CEL/trouble code so I know it was associated with the secondary air punp system. Since the pump sends air into the exhaust ports, if the solenoid valve was open from a cracked hose, that may have caused the noise. Daughter informed me that the noise is gone, car runs fine, no CEL.

I'll send a note your way when I get some better info. I agree with you that it seems to be a very common occurence with the 1.8T engines.

wavinwayne · Dec 9, 2005

Mud,

Definitely do tell which hose it was, as soon as you find out.

I've replaced all of those braided rubber vacuum hoses on my VW, and I still can't get rid of the P0411 code. The secondary air pump works fine, too. It DOES seem a little louder than it was before the CEL came on a couple of months ago, but that may all be in my head.

I suppose there could be a leak in one of the 1" diameter hard plastic air hoses that go to and from the secondary air pump.

One of these days, I'll figure it out. When I do, I'll also post the fix.

eljefino · Dec 10, 2005

I'm glad you guys figured this out on your cars, but I have to wonder what kind of engineers wire an engine control device that way. It obviously should only blow air in the exhaust when the car is running so why not wire it to an ignition-switched circuit?

brianl703 · Dec 10, 2005

It may be a device that has a current draw that is way too high for powering via an ignition-switched circuit.

Engine cooling fans are often wired that way. The fans in my first car, a Dodge Omni, would continue to run for a minute or two after I turned the engine off. As far as I could determine, that is normal behavior, even though there's no need for the fans once you turn the engine off.

Yes, they could have used a relay controlled by an ignition-switched circuit.

By the way, some of Ford's ignition switch problems were stated to have been caused by people adding aftermarket, high-draw current devices to the switched ignition circuit which overheated the switch.

I will only point out that just about all aftermarket car stereos these days draw the majority of their operating current via the unswitched power connection.

moribundman · Dec 10, 2005

quote:

The fans in my first car, a Dodge Omni, would continue to run for a minute or two after I turned the engine off. As far as I could determine, that is normal behavior, even though there's no need for the fans once you turn the engine off.

All the cars that I bought in Europe had that feature. Most people don't want to let the engine idle for minute after high speed driving. If the very hot engine is suddenly turned off, the coolant may momentarily boil over, which isn't ideal. My US import Audi does not have this feature, the Euro version has it. Many cars with an electric waterpump will pump coolant for a while after the engine has been shut off.

tom slick · Dec 10, 2005

A guy at work had exactly the same problem with his VW beetle. sec air pump ran intermittantly until the battery was drained. glad you got it fixed easily.

audi_guy · Dec 10, 2005

Warstud,

Find a service manual that has a diagram of the Secondary Air Induction system and start looking or a broken/loose/cracked hose. If it's under warranty, sounds like a trip to the dealer is in order.

a_g

Warstud · Dec 10, 2005

I've got a Haynes but no mention of Air Pump. Actually I found a some info about them on the web. Found where the hoses hook up to the manifolds and traced them back. One way of finding a vacuum leak is to have someone shut the vehicle off while you look and listen to the engine. Sometimes you'll hear a hissing from the leak after the engine is shut off. The Carb cleaner trick can be used to only as a last resort for me though.

SHOZ · Dec 11, 2005

Most electric SAI pumps are ran via a solid state relay. When these relays fail they usually are in the "on" position. Being hot all the time would drain the battery if this happened.

Most PCMs will control this relay by grounding the signal side. This would also allow a shorted ground wire to turn the relay on at any time.

brianl703 · Dec 11, 2005

quote:

If the very hot engine is suddenly turned off, the coolant may momentarily boil over, which isn't ideal.

The service manual for my mom's car (2004 Malibu Classic with the Ecotec 2.2L engine) states:

"The PCM commands Low Speed Fans on under the following conditions:

After the vehicle is shut off if the engine coolant temperature at key-off is greater than 140°C (284°F) and system voltage is more than 12 volts. The fans will stay on for approximately 3 minutes."

Does the coolant temperature ever get that high under Autobahn-type high-speed driving conditions? Ever since I read that I have been trying to figure out what purpose it serves..it seemed to me that if the coolant temperature is that high, something is seriously wrong and turning the cooling fans on after the engine is shut off isn't going to to anything to help.

secondary air injection pump runs every 5-10 minutes.

Similar threads