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Old 04-07-2014, 05:28 AM   #1
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Post OBD Code 1243 - Dead Secondary air pump


I started my questions on this repair in a different thread and decided to consolidate my questions and document the fix in case someone else has the same issue. Easy fix.

I should mention there are multiple conditions that could trigger a P1243, This simply addresses one of the causes and my action to repair it. Good luck!


Originally Posted by cooljess76 View Post
Secondary air pump rivet failure is a common issue on these cars. Myself and several others have replaced the rivets with nuts and bolts. As for removal, disconnect the hose and you can either unbolt the bracket and remove it as an assembly or simply slide the rubber bushing off of the bracket.
I'll pull the air pump this weekend, but can someone describe which rivets fail here? I'm asking to get an advance idea of what the probable fix is. A pic would be great. Thanks!


Cleared codes last week, drove around, only P1423 reemerged. Arrgghh, I was going to swap diffs today. o well.

So, I'll check the rigid hose and air pump. Are folks referring to the rivets in the top of the pump?


OK, I removed my strut brace, the MAF and the ASC throttle plate assembly to get to the air pump. I removed the rigid emissions tube/hose. The hard hose is intact, no cracks and seems to seal tight. Clips on both end are intact. There was a little moisture in the pipe. Like a teaspoon amount or less.

I removed the air pump by removing the two 13mm nuts, unclipping a rubber carrier for another emissions valve and unclipped the electrical connector at the bottom of the pump. Visual inspection: all rivets look fine, no gaps in the seams between top bottom and middle pieces that the rivets secure. The plastic clips on the pump are all also intact.

I checked for 12v at the red/yellow wire coming into the pump with ignition on. No voltage, but looked in ETK and Bentley and there is a relay from the air pump. I'm not sure how to test the inbound power to the pump.

I applied 12V/grn directly to the air pump. Nothing. May seem obvious, but do these pump motors generally fail? I'll cross check PN# and head out to the yards to see if I can locate an operating one after lunch as a new one is $350. $24.99 at Pick n Pull if you can locate one. Look for a late model 1996+ I suspect the production date should past June, but good to confirm.

It's interesting that this PN# does not show up in REALOem. Am I reading it correctly? 1172 1 432 593


OK, so no pump was available in the local yards on Saturday, but I did find one in a yard about 50 miles away in a 1997 318i sedan Sunday morning. I lucked out, as someone had pulled it, saw the failed rivets and kindly left it intact on the drivers floor.

I tested the pump I found at the pick n pull in the parking lot. It tested fine. The one I found had failed rivets, but it did not impact the testing or operation of its motor. The original one I pulled out of my car failed a power test totally.

So, the motor drives a centrifugal fan. (I didn't know what was under the cap) I went to Ace Hardware and picked up some black Allen bolts and silver nuts with a friction washer. The nylon nuts turned out to be too big. Looked odder. I wish I found some black ones, but the nuts are on the bottom anyway and aren't visible.

I hand tightened the nuts/bolts, plus another 1/8 turn with some red Locktite. The nuts aren't going anywhere. The black allen bolts look almost original. The replacement is in the foreground, with the failed pump in the background.

The air pump is suspended in place with three rubber mounts that attach with 10mm nuts. When you are reassembling the carriers, you can use a 17mm open end wrench to hold the mounts so you don't end up twisting them when you are tightening the nut. I'll order a few replacement mounts as these were pretty soft after 190k miles.

One tip, mark the position of the pump in the two carriers BEFORE you take them apart.

One you have it all back together, reassemble in reverse order as you took it out.

Shortly upon startup, I heard the fan kick in. I guess it has been out for awhile, cause it was a totally new sound. I reset the codes and will drive around, until it either fails again or my reader says I'm good to go retest for SMOG.

I'll take apart the original motor to see why it failed. If I can fix it, I'll keep it as a spare. I never really paid much attention to this pump in the past, I just knew it existed. I know the one on my 540it is larger and still is spinning along.

I hope this helps someone else.


1998 318ti Sport - "Cali" Schwartz II/Schwartz sport interior, Cali top
1998 318ti Sport - "Max" Schwartz II/Schwartz sport interior, S52
1997 318ti Sport - "Tiny" Schwartz II/Schwartz sport interior
1995 318ti Active - "Blanca" Alpineweib III/Schwartz leather interior

Other Current Bimmers: 2006 530i / 2000 2.3L Z3 / 1997 1.9L Z3 / 1999 540it

1997 318ti Sport - "Huera" - RIP
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1995 318ti Sport - "Tiny" Sold
1994 325i Sedan - "Jade" - Sold
1991 318ic - "Bert" - Sold
1985 635csi sold
1984 533i "Max" Sold
1984 318i sold

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Last edited by BlackBMWs; 04-08-2014 at 02:56 AM.
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air pump , p1243 , smog

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