Diagnosing P0411 - Secondary Air Injection System

Rostasteve · 04-13-2013, 09:21 PM

I got a P0411 on my 04 330i, and had trouble finding a good guide diagnosing the root cause. Here's what I did, hopefully it helps someone.

Secondary air injection systems were updated in 04. For <03, see this guide: http://www.bavauto.com/newsletter/20...ter.pdf#page=6. If you have an 04+, read the article since it will be useful and read below.

There are 4 things that can fail: MAF, Pump, Valve, or Hoses. All are located on the right side of the engine bay, behind the window washer fluid reservoir.

http://www.realoem.com/bmw/showparts...15&hg=11&fg=50

All tests must be performed on a COLD engine with a helper.
1. Hoses: Inspect the 2 hoses, make sure they're not torn or popped off.
2. Pump: Have a helper start the engine. Listen and Feel if the pump is working...it should be obvious. If the pump works it should turn on for 5-10 seconds. You can also pull the output hose off and feel for air flow.
3. Valve: On 04+ models the valve is actuated by pressure from the pump. With the engine off, pull the hose off the pump output and blow into it hard. You should feel resistance then the air should flow. If you can't get air through, the valve is stuck shut. If no effort is required to get air through, it's stuck open. Another way is to pull the pump inlet hose and feel for vacuum.
4. If all other tests pass, assume it's the MAF.

Replacement of parts will be obvious or are documented in other threads.

OE Part costs: Valve and MAF are ~$100 each, Pump is ~400. Valve and Pump are made by Pierburg, MAF by Siemens...so OEM parts may work fine too.

Auditr8tor · 04-18-2013, 10:14 AM

Thanks Rosta, I am currently going through this same problem, however I'm still stumped.

This is for a 2005 330ci ZHP

I passed all the tests; pump runs for 5-10 seconds, hoses are good, filter is not clogged, can't manually blow through the valve.

I replaced the MAF, cleared codes, code is back 2 days later.

Can the valve get stuck closed? Is there a way to check the valve? (This is a new style, 03+ valve with no vacuum actuation, so please don't tell me to pull vacuum on the valve)

Other than that, from my research, this could be the small ports in the head that could be clogged.

Rostasteve · 04-19-2013, 07:24 AM

Read point #3 above.

I have an 04 zhp and had the same symptoms as you. Even changed the maf too. Ended up changing the valve (with gasket and nuts) which fixed the problem. I could manually blow air through the new valve but not the old.

jfoj · 04-19-2013, 07:32 AM

Here was my solution - http://forum.e46fanatics.com/showthr...hlight=sap+maf

Rostasteve · 04-19-2013, 06:07 PM

Quote:

Originally Posted by jfoj

Here was my solution - http://forum.e46fanatics.com/showthr...hlight=sap+maf

I actually read your thread prior to changing my maf. No dice, it was the valve. From everything I read, the valve fails most often.

Auditr8tor · 04-19-2013, 07:49 PM

Yeah, I think I wasted money changing the MAF, I should have read Rosta's valve test a little more carefully. I did try to blow through mine and it had a lot of resistance, but I though that was what it was supposed to do.

Has anybody been successful in freeing up stuck valves?

04-13-2013, 09:21 PM	#1
Rostasteve Registered User Join Date: Dec 2009 Location: NJ Posts: 70 My Ride: 04 330i ZHP View My Garage	Diagnosing P0411 - Secondary Air Injection System I got a P0411 on my 04 330i, and had trouble finding a good guide diagnosing the root cause. Here's what I did, hopefully it helps someone. Secondary air injection systems were updated in 04. For <03, see this guide: http://www.bavauto.com/newsletter/20...ter.pdf#page=6. If you have an 04+, read the article since it will be useful and read below. There are 4 things that can fail: MAF, Pump, Valve, or Hoses. All are located on the right side of the engine bay, behind the window washer fluid reservoir. http://www.realoem.com/bmw/showparts...15&hg=11&fg=50 All tests must be performed on a COLD engine with a helper. 1. Hoses: Inspect the 2 hoses, make sure they're not torn or popped off. 2. Pump: Have a helper start the engine. Listen and Feel if the pump is working...it should be obvious. If the pump works it should turn on for 5-10 seconds. You can also pull the output hose off and feel for air flow. 3. Valve: On 04+ models the valve is actuated by pressure from the pump. With the engine off, pull the hose off the pump output and blow into it hard. You should feel resistance then the air should flow. If you can't get air through, the valve is stuck shut. If no effort is required to get air through, it's stuck open. Another way is to pull the pump inlet hose and feel for vacuum. 4. If all other tests pass, assume it's the MAF. Replacement of parts will be obvious or are documented in other threads. OE Part costs: Valve and MAF are ~$100 each, Pump is ~400. Valve and Pump are made by Pierburg, MAF by Siemens...so OEM parts may work fine too. __________________ Imola ZHP Sedan + Bilstein Sport + H&R Sport + PG 3.46 LSD + //M Stut Brace + Rogue RSM + Hotchkis Sways + SS brake lines + UUC black trans mounts Last edited by Rostasteve; 04-14-2013 at 08:46 AM.

04-19-2013, 07:32 AM	#4
jfoj Registered User Join Date: Nov 2009 Location: Fairfax, VA USA Posts: 5,336 My Ride: '06 330CiC, '03 M5 View My Garage	Here was my solution - http://forum.e46fanatics.com/showthr...hlight=sap+maf __________________ Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616 Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501 Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491 Hidden OBC Menu - Check Voltage, Temps, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619 E46/E39 GM5 Door Lock Info - www.bmwgm5.com Lower hose fan switch O-ring - BMW #13621743299

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04-18-2013, 10:14 AM	#2
Auditr8tor Registered User Join Date: Aug 2011 Location: CT Posts: 10 My Ride: 330ci ZHP View My Garage	Thanks Rosta, I am currently going through this same problem, however I'm still stumped. This is for a 2005 330ci ZHP I passed all the tests; pump runs for 5-10 seconds, hoses are good, filter is not clogged, can't manually blow through the valve. I replaced the MAF, cleared codes, code is back 2 days later. Can the valve get stuck closed? Is there a way to check the valve? (This is a new style, 03+ valve with no vacuum actuation, so please don't tell me to pull vacuum on the valve) Other than that, from my research, this could be the small ports in the head that could be clogged.

04-19-2013, 07:24 AM	#3
Rostasteve Registered User Join Date: Dec 2009 Location: NJ Posts: 70 My Ride: 04 330i ZHP View My Garage	Read point #3 above. I have an 04 zhp and had the same symptoms as you. Even changed the maf too. Ended up changing the valve (with gasket and nuts) which fixed the problem. I could manually blow air through the new valve but not the old. __________________ Imola ZHP Sedan + Bilstein Sport + H&R Sport + PG 3.46 LSD + //M Stut Brace + Rogue RSM + Hotchkis Sways + SS brake lines + UUC black trans mounts

04-19-2013, 07:49 PM	#6
Auditr8tor Registered User Join Date: Aug 2011 Location: CT Posts: 10 My Ride: 330ci ZHP View My Garage	Yeah, I think I wasted money changing the MAF, I should have read Rosta's valve test a little more carefully. I did try to blow through mine and it had a lot of resistance, but I though that was what it was supposed to do. Has anybody been successful in freeing up stuck valves?