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Secondary Air Pump & Valve

103K views 92 replies 49 participants last post by  316buc 
#1 ·
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?
 
#2 ·
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.
 
#5 · (Edited)
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.
 
#7 ·
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?
 
#8 ·
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.
 
#9 ·
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?
 
#12 ·
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..
 
#13 ·
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.
 
#16 ·
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.
 
#21 ·
You only do an immediate oil change (i.e. within 100 miles) if you add Seafoam to the crankcase. This is a way to clean the engine internals when you are planning an oil change.
When you run Seafoam through the Secondary air valve you don't need to change the oil, you will see the Seafoam and carbon deposits burn off in the white smoke.
 
#23 ·
Please check your hose! When pouring in the seafoam I saw a leak. It was about the size of a pin head. I replaced the hose. When I went to pull it off it was completly drie rotted from the inside. I have not even seen a hose this bad in the restoration jobs I have done and some of those hoses were still OEM from the 60's.
 
#26 ·
Seafoam not flowing down

The air pump's working since I can feel the airflow after I disconnected the hose. But the seafoam stayed in the hose after even 3 5-sec cold start. I left the seafoam in the hose, drove around, parked around overnight for it to soak in, but the seafoam's still mostly there the next day!

Does this mean I have bad valve or vac line? How do I make sure the seafoam gets in to rid the likely blockage before I can diagnose other issues
 
#27 ·
The air pump's working since I can feel the airflow after I disconnected the hose. But the seafoam stayed in the hose after even 3 5-sec cold start. I left the seafoam in the hose, drove around, parked around overnight for it to soak in, but the seafoam's still mostly there the next day!

Does this mean I have bad valve or vac line? How do I make sure the seafoam gets in to rid the likely blockage before I can diagnose other issues
You probably have either:
A bad vacuum hose
a plugged valve
or both.

I just replaced the entire vacuum line from the vacuum valve on the rear of the intake manifold to the Secondary Air Valve on the front of the cylinder head.

The best thing to do is to remove the cabin air filter housing, the coil cover, and the fuel injector cover. That way you can see the entire vacuum hose/line assembly. My vacuum hose was broken, as was my vacuum hard line. You can get the part numbers from the Real OEM site, and the parts run about 25 bucks.
 
#31 ·
let me get the straight.
1- unplug the hose
2- pour sea foam in hose
3- while hose is unplugged run the car for 5 sec OR do i plug the hose back on?
4- repeat this 3 times at least.
5- plug everything back together.
6- expect white smoke.

let me know thanks guys!
 
#33 ·
Did this today and poured the seafoam...turned car on for a couple of seconds then went back to check...seafoam still in there...did it a couple more times to see if it will go down...nothing coming out the secondary air pump...is there suppose to be air coming out? Or is it possible that I let the car warm up too much for it to work?

Sent from my SPH-D700 using Bimmer App
 
#35 ·
My SES light is on as well and having some rought idling once in a while with the cold start. Went to a mechanic shop and got the codes read and they suggested cleaning my fuel system. They recommended something other than seafoam due to it being harsher, possibly more corrosive. I wasnt too sure what to think of his advice so was wondering what you guys think. I did however buy some gumout and put it in my fuel tank. Before I try this I just want a good solid answer to whether seafoam could harm my car.
 
#36 ·
As far as I know...seafoam won't harm anything in your car

Sent from my SPH-D700 using Bimmer App
 
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