Potential O2 Sensor Problems - United Bimmer Community

**Rooz** · 05-27-2005, 11:44 AM

OK, My car came back from getting it's new started put on yesterday. Once i got it back I was like "Weird, my car feels slugish", but then I thought, must be bcs I was driving my mom's 540i (V8 BMW, very fast).
SO, I was driving around yesterday, and all a sudden I see that damn "Check Engine" light come on

. SO I figured that the mechanic must have forgot to put something back or soemthing like that. So today I plug the obd-II code reader, gives me a P0155 code: O2 Sensor B2 S1 Htr Circuit Malfunction . So, the 02 sensor of the second bank sensor 1 has a heater circuit malfunction. I erased it, and who knows maybe it won't come back, but since my car is kinda slugish and am not getting as good of a gas mileage as before, I am assuming that it is in fact bad. Now I heard that this is somewhat of a common problem in our cars... So, anyone got a DIY on this, or any ideas on how big of a hole this will dig for me? Any help would be more than apreciated.....

An also, what is the difference between the O2 Sensor Heater Circuit and the o@ Sensor it's self? Bcs bare in mind if gave me a Heater Circuit Malfunction, not the O2 sensro it's self....

**cruzin 323is** · 05-28-2005, 09:37 AM

i think the heater curcuit and jsutt he sensor would be the same thing.. but i'm not too sure...

i don't remember if u said it or not.. but there are 2 02 sensors.. do u know which 1 it is??

**Rooz** · 05-28-2005, 01:51 PM

Ok, well, I sucked my pride in and went bck to my dad's place (My dad and I tend to not get along too well, lol) Well, his mech said I should reset the sensor, so I did, and drove the car for about 30 miles (took it on the hwy for about 80-90 for a good 10-15 mins) and we scanned the car again, and turns out that one of my upstream O2 sensors is "lazy" it's not gone yet, but it will die on me within a month or two. So, that's that....

**Antiburn** · 05-28-2005, 02:51 PM

So replace it. It shouldnt take you more then 10 minuets max. If you have acces to a lift it makes it that much easyer. Only hard part sometimes is getting it broken loose. Spray some de-locker crap on it and give it a shot.

**Rooz** · 05-28-2005, 03:21 PM

Well, humm am going to wait a little, reason is, I JUST replaced my starter and I already ordered my ZKW's so I am going to wait a good two weeks before I purchase anything major like that again....

**Rooz** · 06-07-2005, 09:53 PM

Well, since I have to make a trip to ATL soon, I ordered it yesterday, came in today, and going to see how to replace it (It's an upstream one) B2 sensor 1 .... any clues, anyone?

**komodo** · 06-07-2005, 11:21 PM

I'm about to tackle a similar problem, only with O2 simulators I'm about to order. heh

See if this helps: http://www.pelicanparts.com/bmw/tech...-O2_Sensor.htm

**komodo** · 06-07-2005, 11:25 PM

Here's another DIY written by Filip75:

Quote:

Originally Posted by Filip75

I've done this on a 1995 318ti. I'm not sure, but it might be a little different in other E36s.

If you have STOCK stereo, make sure you have the ACTIVATION CODE for it before proceeding

1. Open up your hood and disconnect the "negative" clamp on your battery

2. Jack up your car. Stands are preffered, so you have the most amount of space to work at...I used the lift, so it was a cake walk for me :-)

3. Look at your Exhaust. Backtrack it from the muffler, past the CAT and you will see a plug screwed into the side of exhaust.

4. Track the wire from that plug to the plastic connector (right beside the ATF fluid pans).

5. That plastic connector rests in the bracket. The bracket is being held by a bolt. To get easier access to the plug, undo that bolt and the bracket will sag down letting you disconnect the plug with ease.

6. Now, that the plastic part is disconnected, go ahead and unscrew the sensor from the exhaust. It WILL be tight

Installation is the reverse of instructions above.

INFO: When I installed mine, the wire on a new sensor was almost 2 times longer then the original's. I Lock-Tied it to one of the flex bars right there. Make sure, that the wire doesn't come in contact with HOT parts (exhaust & ATF pans)

**Rooz** · 06-07-2005, 11:27 PM

Thx Komodo, I guess am gonna go tlak to my dad's mechanic before he leaves... lol

**xsperf** · 06-08-2005, 12:24 AM

heres my little tip: just be careful when removing it, its ont he exhaust(i thinkthats where yours are, i did this on OBDI) and those bolts are tough, spray some PB on it, and take a breaker bar, and DONT strip the bolts, if you do strip the bolts, heres a little trick i learned that always works:

head up the bolt till its red hot,then dump cold water on it, should come out w/ a vice grip

**Rooz** · 06-08-2005, 08:24 AM

^^ Thanks but the one that's bad is one of the Upstream ones, hence not the ones right before the cats.... apparently it's close by the manifold...

**Rooz** · 06-08-2005, 04:34 PM

Well, Finally changed the darn thing! Yeap, car is much better now

witeshark · 06-08-2005, 04:57 PM

Great news, very useful thread fo the E36's

**komodo** · 06-08-2005, 07:35 PM

Awesome job.

You should have taken pics and made a good diy for ub.c. haha

**Rooz** · 06-08-2005, 09:09 PM

Quote:

Originally Posted by komodo

Awesome job.

You should have taken pics and made a good diy for ub.c. haha

Would have but my dad's mechanic is leaving for his vacation tomorrow, he was pushing em bcs he wanted to use the lift I was using after me... However, I did take pics of my exhaust to see what is involved in the m3 exhaust swap