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DIY: Do It Yourself
Post here to share or improve your wrench turning skills! All BMW E46 DIY tips, tales, and projects discussed inside. Learn to work on your car and know the right BMW parts you will need!

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Old 03-24-2006, 08:48 PM   #21
r0x
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Quote:
Originally Posted by Tom Busby
Awesome write-up and pictures on this thread by rOx.

And prescient screenname-choice by rOx don't you think?
Thanks. You're too much, Tom!

Hey, if I could afford to replace four oxygen sensors at once,

1) I wouldn't be working on my BMW by myself
2) It would be a Ferrari, not a BMW.
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Old 03-25-2006, 02:27 PM   #22
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Awesome write-up!


Clear, concise and helps save the moolas that those bmw dealers steal......
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Old 03-25-2006, 03:51 PM   #23
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Quote:
Originally Posted by FFWD
According to my shop, only the two pre-cat sensors are shorting. They said I should change all four since the two post-cats will probably go within a few months.
I doubt that. The Post-Cat O2 sensors mainly deal with emissions monitoring and if there were a problem you would most likely not find out unless you failed emissions due to an annual inspection.

If you want preventative maintenance then let the shop do them. But honestly they won't go in a couple of months BTW how many miles on your car? O2 sensors supposedly are able to hold out for 100,000 miles.

I replaced all 4 for preventative maintenance purposes around 55,000 miles give or take

Jared
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Old 03-30-2006, 11:06 PM   #24
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Quote:
Originally Posted by Ivegotissues666
I doubt that. The Post-Cat O2 sensors mainly deal with emissions monitoring and if there were a problem you would most likely not find out unless you failed emissions due to an annual inspection.

If you want preventative maintenance then let the shop do them. But honestly they won't go in a couple of months BTW how many miles on your car? O2 sensors supposedly are able to hold out for 100,000 miles.

I replaced all 4 for preventative maintenance purposes around 55,000 miles give or take

Jared
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Old 07-18-2006, 08:02 PM   #25
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is there anywhere else to get 02 sensors cheaper?? bavauto.com sells them for 100 for pre-cat and 110 for post cat each. i need to get mine replaced as well since they are throwing the SES light.. codes p1188 n p1189..

after reading.. it seems that usually the pre-cat sensors are the ones that need to be replaced rather than the post cat.. does p1188 and p1189 mean that both pre and post sensors need to be replaced ?? why are there two codes? thanxx
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Old 07-18-2006, 10:08 PM   #26
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Before you go and spend the money on the O2 sensors, make sure that's actually your problem. Although all my errors indicated O2 sensors, the root cause turned out to be a defective crankcase vent valve (aka oil separator). My shop wanted to charge me $1500 to change all 4 O2 sensors. Luckily I went for a second (and third, and fourth) opinion, and decided to try replacing the $50 part first (although the labour to do so turned out to be a nightmare). Once that part was replaced and the codes reset, car has been fine. Telltale signs are a fog horn sound when you turn your engine off.

Quote:
Originally Posted by 6strings
is there anywhere else to get 02 sensors cheaper?? bavauto.com sells them for 100 for pre-cat and 110 for post cat each. i need to get mine replaced as well since they are throwing the SES light.. codes p1188 n p1189..

after reading.. it seems that usually the pre-cat sensors are the ones that need to be replaced rather than the post cat.. does p1188 and p1189 mean that both pre and post sensors need to be replaced ?? why are there two codes? thanxx
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Old 07-18-2006, 11:11 PM   #27
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Great, clear DIY. Nice job on the writeup.
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Old 07-19-2006, 07:23 AM   #28
6strings
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Quote:
Originally Posted by FFWD
Before you go and spend the money on the O2 sensors, make sure that's actually your problem. Although all my errors indicated O2 sensors, the root cause turned out to be a defective crankcase vent valve (aka oil separator). My shop wanted to charge me $1500 to change all 4 O2 sensors. Luckily I went for a second (and third, and fourth) opinion, and decided to try replacing the $50 part first (although the labour to do so turned out to be a nightmare). Once that part was replaced and the codes reset, car has been fine. Telltale signs are a fog horn sound when you turn your engine off.
there is a fog horn sound but its not a loud sound.. when i turn my engine off i have to open the door in order to hear that sound. it sounds like the fan turns off and then theres this faint little fog horn sound like "errrrr" for a few seconds.

where can i find this 50 dollar part? is it a diy? all the signs point to o2 sensors tho.. slower performance, delayed acceleration.. did u still get these signs even with that defective crank case valve?? thanx for ur input!
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Old 07-22-2006, 10:31 AM   #29
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Yeah I wanna Know where to get the $50 dollar part and the DIY on it.
I replaced the Pre-cat O2 Sensors but the light is still on and The car won't start after its been on for awhile. Or what else could the problem be?
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Old 11-07-2006, 12:59 PM   #30
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Originally Posted by 6strings View Post
is there anywhere else to get 02 sensors cheaper?? bavauto.com sells them for 100 for pre-cat and 110 for post cat each. i need to get mine replaced as well since they are throwing the SES light.. codes p1188 n p1189..

after reading.. it seems that usually the pre-cat sensors are the ones that need to be replaced rather than the post cat.. does p1188 and p1189 mean that both pre and post sensors need to be replaced ?? why are there two codes? thanxx
Did anyone ever know the answer to this question? I'm getting both P1188 and P1189 codes too. I sure would like to know if I can narrow the problem down to specific O2 Sensors.

Thanks
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Old 11-07-2006, 09:16 PM   #31
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Do a search on "fog horn" in the DIY forum. Here's one of them. Note - this is a pain in the a$$ DIY. I'll see if I can find the part number for you also.

https://forum.e46fanatics.com/showthr...light=fog+horn

Quote:
Originally Posted by 6strings View Post
there is a fog horn sound but its not a loud sound.. when i turn my engine off i have to open the door in order to hear that sound. it sounds like the fan turns off and then theres this faint little fog horn sound like "errrrr" for a few seconds.

where can i find this 50 dollar part? is it a diy? all the signs point to o2 sensors tho.. slower performance, delayed acceleration.. did u still get these signs even with that defective crank case valve?? thanx for ur input!
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Old 11-07-2006, 09:21 PM   #32
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And here's another thread with a link to the RealOEM site and part numbers. You'll probably want to replace all the hoses and tubes while you're at it, especially if the car is older. Make sure you double check with the dealer if your car is a cold weather model or not. Two dealers told me different things after providing my VIN to them. I ordered the non-cold weather model (even thoughI am in Canada), and ended up with the wrong hoses. The valve fit fine, though.

https://forum.e46fanatics.com/showthr...light=fog+horn
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Old 11-11-2006, 12:44 PM   #33
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Thanks for the write-up... I'll be doing this later today. I had to buy the O2 socket and the 12" extension. You do need that extension I can tell you that.
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Old 11-11-2006, 05:35 PM   #34
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One thing which you did not mention or I missed it is that the you need to do this when the engine has just recently been run and the engine is hot.

This will enable to O2 sensors to be more easily removed. Doing it while the engine is cold could resort to stripped O2 sensor head or the threads which is NOT good.
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Old 07-21-2007, 01:25 AM   #35
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Thread revival time! Excellent write up! okay I Need the OEM part number for the pre cat sensors. NE1 have them? I found the post cat sensor DIY. Cross-linking for reference: https://forum.e46fanatics.com/showthread.php?p=4719022

btw, pre-cat sensors are running $93 each at bavauto. NE1 have a better place to get them from?
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Old 07-21-2007, 03:00 AM   #36
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found a good flowchart to add to this writeup: http://www.obd-codes.com/trouble_cod...1-sensor-1.php
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Old 09-29-2007, 10:19 PM   #37
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just did this I found removing the secondary air pump and the windshield wiper reservior (which is very easy gave more room for the sensor closest to the bumper. My old sensors look identical to the ones in this thread, I thought it was so white and ashed from the Seafoam stuff

Last edited by joserse46; 09-29-2007 at 10:21 PM.
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Old 02-17-2008, 05:50 PM   #38
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Just used this DIY to do the sensors in my 2000 323i. Was easy as pie, and reading this was a HUGE help. The only dumb move was when we switched up the wiring harnesses, car ran like crap. Quick fix though.
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Old 02-22-2008, 08:49 PM   #39
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doing this tomorrow...hopefully this fixes my rough idle and misfire issue. even after changing coils, plugs, boots, disa, cleaning MAF, new stock Air Filter, sea foam, and some other things.
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Old 02-22-2008, 09:37 PM   #40
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Originally Posted by emg2919 View Post
doing this tomorrow...hopefully this fixes my rough idle and misfire issue. even after changing coils, plugs, boots, disa, cleaning MAF, new stock Air Filter, sea foam, and some other things.
Are you getting an SES light?
You might wanna check out this thread as well:
https://forum.e46fanatics.com/showthread.php?t=342081

After 2 months of fishing for the cause of rough idle on my car, it turned out to be the same problem discussed in there.

Good luck!
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