[RiFTy80]

Over the past year+ my 2003 330xi has given the "secondary air flow too low" code 3 times. No associated symptoms. So, hardly a pressing issue. The dealer says I need a new secondary air pump and valve and the service will cost over 700 bucks. From what I have read on this forum, the valve typically goes bad first and ultimately causes the demise of the air pump. I am thinking since the error code pops up so rarely, perhaps the air pump hasn't gone bad yet and I can get away with just replacing the (much cheaper) valve.

Is this wishful thinking or am I on to something?

Can anyone point me to a DIY on this?

 

[xi_ter]

Fortunately I had my secondary air pump and valves replaced under the CPO warranty. But my CEL returned several times. Which led me to feel that carbon build up in the exhaust valve passages used by the secondary air system, like the 540 in the pic was causing the low flow.

To clear this carbon, pour Seafoam into the hose from secondary air pump to the valve and engine port before the cold engine is started in the morning.

The hose will hold just over an ounce of Seafoam. Reconnect the hose and run the car 5 seconds so the air pump blows the Seafoam into the exhaust port. Repeat this fill and restart 3 more times only running the engine 5 seconds so the secondary air pump runs for the 3 fills.

Then let the engine sit 15 minutes and warm up the car. There will be significant amounts of Seafoam carbon burnoff in the form of white smoke. The carbon burnoff will clean exhaust areas in the path to the O2 sensors that measure secondary air flow.

Since doing this using a couple of cans over a few months, the CELs have gone away and the engine feels smoother.

 

[ixtoxi]

Here is all you need to know to diagnose your problem:

http://www.bavauto.com/newsletter/2008_n408_newsletter.pdf#page=6

 

[RedTRex]

Question.
NVM

 

[refimail]

To clear this carbon, pour Seafoam into the hose from secondary air pump to the valve and engine port before the cold engine is started in the morning.

Thanks xi_ter. The Seafoam did the trick. I've been troubleshooting P1418 SES code for over a year, literally replacing almost every component of the secondary air system, and the Seafoam cleared it in seconds. Many thanks.

 

[xi_ter]

Good to hear Seafoam worked for your secondary air codes too :thumbsup:

 

[hendrich]

my air pump doesn,t turn on when i cold start my car, i unplugged it and connected it directly to a battery and does not turn on. you guys think it might be fried?

 

[xi_ter]

Probably fried unless your test circuit wasn't grounded. Do step 3 of the BavAuto diagnostics to see if you get power to the pump on start up in case of fuse issues. In my case under CPO warranty, BMW replaced the secondary air pump first - but the codes didn't disappear until the Seafoam in the tubing trick.

 

[veener88]

I am getting the same error code with our 2000 323I. P1423 and P1421. I cleared the codes off the car Thursday night and they did not come back till Saturday night. About 2-3min after the car started. The car is getting worse gas millage after the codes go on.

The car has 150K on it. Sould I try the Seafoam first?

 

[xi_ter]

It's better to try the Seafoam treatment first because it's an easy first step. See in the above post. It may be all that is needed to clear the low flow codes. After 150K you should repeat the cleaning process several times.

 

[dexx_x]

Thanks xi_ter. The Seafoam did the trick. I've been troubleshooting P1418 SES code for over a year, literally replacing almost every component of the secondary air system, and the Seafoam cleared it in seconds. Many thanks.

Did your SES light come off after next cold start? or did you have to get the light reset?


I put some seafoam into the hose this morning (just once), and the amount of smoke that came out of the exhaust scared the s#!t outta me!

 

[Elkhound]

Funny, I have an 03' 330xi too, and I was recently told that a problem could be starting with my secondary air pump, but if so, it won't be getting worse now in the warmer weather. Said I'll have to wait until next fall/winter to see if it starts up again. Symptom was shifter/wheel/engine shaking from side to side as if an engine or transmission mount was loose.. But it goes away pretty fast after the car starts moving and the engine begins to warm up..

 

[xi_ter]

Funny, I have an 03' 330xi too, and I was recently told that a problem could be starting with my secondary air pump, but if so, it won't be getting worse now in the warmer weather. Said I'll have to wait until next fall/winter to see if it starts up again. Symptom was shifter/wheel/engine shaking from side to side as if an engine or transmission mount was loose.. But it goes away pretty fast after the car starts moving and the engine begins to warm up..

All that vibration could be your secondary air pump. The secondary air pump automatically shuts of in about 2 minutes. The Seafoam treatment could eliminate some of the back pressure.

 

[dexx_x]

So two days after the seafoam treatment and my check engine light is off...

Thanks xi_ter for the tip

 

[jcs325iT]

I had a broken vac line at the valve, the 1st piece off the valve to the plastic pipe about 4" long that gets cooked by the exh. manifold heat over time.....cleared the codes and all is well.

 

[veener88]

Good to hear. I got the seafoam today at Napa. Doing the cleaning tomorrow morning with the engine nice and cold. I had 6 good cold starts because the cell came back so I am guessing the accual hardware is working correct. The clogs are causing the issue not the show right away. Will use the seafoam tomorrow. Clear and the codes and see if they come back again.

 

[veener88]

OK did this just now. Car feels a lot smoother at idle. Power seems to be better too. I cleared out the cels. See what happens now.

 

[refimail]

Did your SES light come off after next cold start? or did you have to get the light reset?

The SES light turned off on its own after the first treatment (1/2 bottle) but, although the light was off, my Peake was still able to read the error code. I had to manually clear it.

 

[bimmer94]

So do you have to do an oil change after the seafoam? Ive heard both ways and dont want to do it unless Im completely sure

 

[kelis_ac]

I don't know if you Have to change it, But I will do this treatment tomorrow and then Change my Oil next week cause I need to anyway...