Secondary Air Problem !!

Help I have a problem on a '03 325i and I'm at my witts end.. first, I replaced the air injection inlet valve,(no vacum hose) thinking it could be clogged or malfunctioning. Then, I checked the air pump and it blows like a leaf blower gone mad, but the secondary air pump will only stay on for 3-5 seconds on a cold start and then throws a SES light. I understand the purpose and process of the secondary air injection system. The system is monitored via the use of the pre cat O2 sensor. If the sensor reading remains unchanged after a predetermined time a fault will occur. However, the error code does not indicate a faultly O2 sensor! What next relay?
Thanks in advance

Relay. Pink and behind the glove box. This fixed mine.

If changing a relay doesn't help, there could be a blockage somewhere after the valve inside the engine.

I think someone on here poured seafoam into the valve after warming the car up, then hooked the airpump back up started the car to get it in the system, shut the car off and let it sit for a few hours. Crazy, but it may help.

My secondary air low flow code cleared by filling the tube between the pump and the exhaust valve with seafoam. Then start the engine for about 4 seconds so the Seafoam is blown in the exhaust valve. Repeat this about 3 times and then let sit 20 min.
Start the car and an amazing amount of carbon will burn off the valves. Repeat these cold start seafoam cleanings a few days later. There will be more air flow and the code will eventually clear. Mine has been clear for 2 years now.



Review clamp and pull tube away from secondary air pump



Fill to the top of the hose with Seafoam. Reattach and start car for 4 sec. Repeat 3 times since the secondary air pump only operates while the engine is cold.

OK, OK I give up, what is the answer? I replaced the relay and still NO GO.. I did the seafoam thing and NO GO.. Let me review what I have done and what has been replaced. #1 Replaced air injection inlet valve (no vacum line) remember this is a late '03 325i with less than 80k on it. (However, the valve did need to be replaced). #2 Replaced the SAP. I could hear the bearings starting to go, so I found a SAP local that was better than mine (less than 40K on it). Bench tested the SAP worked great! Installed in vechicle worked great! The pump would run for about 5 sec or less on a cold morning (below freezing) and shut off ,then the SES light would pop on !! Error indicating SAP malfunction. Which brings me back to the relay and seafoam deal. Oh oh, one more thing I did replace the Mass Air Intake for the SAP, it came with the pump. So I have replaced everything execpt the kitchen sink, which is next week.. So if anybody out there has another idea or has had the same problem, I'll give it a try. The not so funny part about this, is that the SAP will run for appox 5 seconds or less on a cold morning then shut off and pop an error code.. I know, I know this is a TEST and I Failed so PLEASE help soon!! Thanks again in advance.

Only place to go next is further down the line. You did the pump and valve. Did you do the hose in between? Maybe the electrical connection needs a good cleaning? (Many of our 'water tight' connectors seem to lose their gasket...I always look and clean connections with electrical cleaner)

There's a great troubleshooting link here about the SAP--I think it's at bavauto.com, but I'm not sure.

Have you checked the following system, located back of the engine?

Check #5 vacuum control valve, #6 non-return valve and other hoses. I'm guessing #5 is your prime suspect

Mack I was thinking that too, but I thought he said he didn't have a vac line leaving the valve. IDK about that design, but OP, if you do have that vac line, follow it around like Mack suggested.

^Yeah he said "I replaced the air injection inlet valve,(no vacum hose)", "#1 Replaced air injection inlet valve (no vacum line)".....
I think he meant (did not replace vacuum hoses), any kind of EGR valves have some sort of vacuum hose right?

The 2003 and newer models don't have the vacuum line. They are a blow through system. Something is shutting down your SAP prior to it achieving its goal. Was the SAP that you bought with 40K from a 2003 or newer car? If not it is a different pump. Is your SAP filter clean? Did you soak the passage with SeaFoam?

Guys, Guys the sytem looks like this:


*******>********>

See, no vacum line from the valve (#17). If the valve had a vacum line, that would be one of the first things I would check. The air valve is a one-way air flow valve. It mounts directly to the cylinder head, with a passage machined through the head to allow the air punp to inject air/oxygen directly into the exhaust manifold. This eliminates the external air injection manifold distribution pipes to the manifold. The whole system is monitored by o2 sensor. I can't belive that I'm the only one that has had this problem. I have to agree with DMax that it must be something electrical, but I don't know what. The valve works, the pump works However, the pump will only run for a short time and then shut down and throw a SES light !! Thanks Guys, if you hear of a solution or any more ideas let me know.

Anyway, relay sounds like a decent shot...it looks to be the same 'tint' as the foglight relay, but Bentley is black and white, so I don't know. If they're the same color, though, you should be able to swap them...just like the Fuel pump/horn relays.

GL...hth

^Doug, here you go. http://www.realoem.com/bmw/showparts...g=50&lang=enUS
Mmmm indeed no vacuum hose....How's #2 air filter and how's the connection of #3 air mass sensor? If #3 really is the problem, BMW scanner will give you specific code indicates air mass sensor failure.

What is the code?

This secondary air system was introduced in 03/2003 with the change to the MS45 ECU.
Is the code about a mass air flow sensor? that would be part number 3 in your drawing.

Stickbuilder-- Yes, the new SAP is the same part# 1172571589 and it blows like a leaf blower on 220 V . The SAP filter was replaced, I did check it, it is clean. I did the seafoam thing a couple of months ago, alot of smoke. I agree with you, there is something that is preventing the SAP from continuing to run. I'm leaning toward electrical because everything else works. What do you think ?

The error code is Peake 2761 "secondary air system " No other codes..

Originally Posted by sgtfury40

Relay. Pink and behind the glove box. This fixed mine.

Missed this. Seems easy enough to check.

If you know your electrical stuff, maybe you could test plausibility of signal you're getting from that maf.

Wish I could get a replacement filter for my sap. I looked a while back and couldn't find it...maybe I'll try again!

If you don't care about "emissions" scrap that ****, it's fukcing useless anyhow.

The relay in question is in the smaller of the 2 relay bays. This one is to the left on the face of the fuse tray. You will need a 10mm socket and something to cut a zip tie to remove it. The larger tray holds something on the order of 5 relays and yes, there is a salmon colored relay there as well. It is the Horn relay. In the smaller bay, there are only 2 relays. One is Black, the other is Salmon or pink. The salmon colored one in the 2 relay bay is the one that you want to change. I don't know exactly where the signal to this relay is generated, but it does use time and exhaust temperature to set the run time.

OP, you don't by some chance have aftermarket headers and cats on your engine do you?

Replaced the Relay this weekend and still NO GO.. No, I don't have headers and cats on the car. There is something that is preventing the SAP from continuing to run.