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p0411 - please help - Audi A4 B5 Quattro 1998 2.8L

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p0411 - please help - Audi A4 B5 Quattro 1998 2.8L

Old 02-17-2014, 06:24 PM
1st Gear
Thread Starter
Join Date: Feb 2014
Posts: 2
Red face p0411 - please help - Audi A4 B5 Quattro 1998 2.8L

I have a 1998 A4 2.8L Quattro that I'm trying to rescue.

When I picked it up on lien sale it had been sitting for 6 months. It had a quite a few codes on it which I was able to clear up. I'm down to the one final code now that is driving me nuts! I can't smog the car with the code cleared as as the readiness is not set and I'm running out of time on my 30 day permit.

The code I get is a P0411. One handheld OBD2/CAN scanner doesn't report the actual message. The other scanner reports the message for the code as "P0411 Secondary Air Injection System Incorrect Flow Detected". 16795 Vag-Com reports the code as Secondary Air Injection System: Incorrect Flow Detected.

I've checked and replaced as many of the vacuum lines as were replaceable. The vehicle has no vacuum leaks and idles with 18" of vacuum. I've checked the combination valve, the two solenoid valves, the secondary air pump, and relay/fuse with a hand vacuum pump and using the Vag-Com output tests. I've double checked all of the above and put clamps on the vacuum line connections that seemed like they might need it (sections where the thicker line joins the thinner harder stuff and there's a nipple missing).

Readiness monitors are reset as follows:

After clear all the codes, the readiness monitors for EVAP and Secondary
Air are still incomplete and then also the CAT monitor is incomplete.

So the cycle seems to be:

[codes cleared]

CAT monitor is incomplete
EVAP and Secondary Air are still incomplete


CAT monitor BECOMES complete
EVAP and Secondary Air are still incomplete


P0411 code appears
CAT monitor is complete
EVAP and Secondary Air are still incomplete

4. Reset codes goes back to step 1.

I've followed the drive cycle recommendations for both my Audi A4 2.8 (AHA) as well as the generic ones.

An additional part of the puzzle:
There is an issue with the shifting (automatic/tiptronic) in which shifting up from some of the lower gears (fromfirst gear to second gear, and from second gear to third gear) will delay the shift (as if the clutch is in) so that the RPM's will jump unless you ease off of the gas. When it does go into gear after the delay it usually goes in hard due to the RPM mismatch.

I read somewhere that the readiness test drive cycle will be cancelled if the RPM's exceed 2800/3000 RPM and sometimes it's inevitable that the RPMs jump during a shift (if you ease off the gas sometimes you get left at a lower speed where the upshift is no longer necessary).

I've heard that I may need a new transmission or possibly a transmission speed sensor.

Please help me get this thing to be smog friendly!

Old 02-17-2014, 09:15 PM
1st Gear
Thread Starter
Join Date: Feb 2014
Posts: 2
Default additional detail: How I tested the pump and combi valves

I tested the pump and combi valves as follows:

For the pump:
1. I made sure that the secondary air pump runs for about a minute an a half when the car is cold started.
2. I triggered it via the Vag-Com Engine-01 output test. It would cycle on and off (at about 1 second intervals).
3. I also made sure there was 18" of pressure established on the vacuum lines using a gauge.
4. I also checked the hoses:

I pulled the OUTPUT hose and checked it for integrity visually and by blowing into it while holding my finger on the other end. I made sure the connection both snapped on positively.

The INLET hose that leads to the pump (the larger diameter one) does not make a positive connection to the air pump as one of the clasps on the [90 degree] end piece is broken. I noticed this by virtue of the fact that someone previously had used zip ties to attempt keep it attached. Could this cause an issue with the efficiency of the pump (assuming at some point it became disconnected and ran that way until found?

For the combi valves:

I tested them to see if they held pressure by pumping back into the them with a hand vacuum pump.

Last edited by escape; 02-18-2014 at 02:05 PM. Reason: Clarify hoses
Old 04-25-2015, 06:33 PM
1st Gear
Join Date: Dec 2007
Posts: 64
Default Did you ever get this fixed?

My '99 A6 2.8 QT (150k) has the same code and the transmission is doing the same hard shifting in low gears. It has been a long term problem that is a minor annoyance but hasn't got worse over time. I am moving soon to an area which requires smog testing and I need to get this fixed. Did you ever figure yours out?
My transmission shifts normally under hard acceleration and when using the tiptronic mode so I don't think the fault lies in the transmission. Also I can clear the code and drive the car for several days without the CEL, but it always comes back eventually, and is "not ready" in the interim.
I have recently replaced the valve cover gaskets and replaced all of the vacuum lines at the same time. The code was present before and after so I am confident that it is not a vacuum leak.

Any help greatly appreciated.

Thanks, Mike
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