weird CEL... - United Bimmer Community

**lecchilo** · 03-14-2006, 02:52 AM

today, i cut out my cats, put in o2 sims and something weird happened.... when everythign was done, the CEL came on and gave out the code for pre cat sensors heating something... p0155 i think, 1137 bmw code. weird thing is, it won't turn off... we tried erasing the code with both peake tool or regular obdII tool and it won't erase it....
comments?
oh we also tried disconnecting the battery for a while..

**tomctx** · 03-14-2006, 08:29 AM

One of the 02 sims bad?

**komodo** · 03-14-2006, 08:33 AM

Hum, I had an issue like that with my sims as well... I don't remember how I fixed it, but have to run now, I'll think about it and update this post later when I figure it out.

Sorry I can't be more help, but there is a fix.

**lecchilo** · 03-14-2006, 10:29 AM

Quote:

Originally Posted by tomctx

One of the 02 sims bad?

they're brand new (well like 200 miles old)

**lecchilo** · 03-14-2006, 06:43 PM

Quote:

Originally Posted by komodo

Hum, I had an issue like that with my sims as well... I don't remember how I fixed it, but have to run now, I'll think about it and update this post later when I figure it out.

Sorry I can't be more help, but there is a fix.

did you remember yet ??

**xsperf** · 03-14-2006, 07:14 PM

Quote:

Originally Posted by lecchilo

today, i cut out my cats, put in o2 sims and something weird happened.... when everythign was done, the CEL came on and gave out the code for pre cat sensors heating something... p0155 i think, 1337 bmw code. weird thing is, it won't turn off... we tried erasing the code with both peake tool or regular obdII tool and it won't erase it....
comments?
oh we also tried disconnecting the battery for a while..

fixed.

lol jk, but i have no idea man, i would suggest emailing whoever you bought your 02 sims from or the actual company that made em

**lecchilo** · 03-14-2006, 08:05 PM

Quote:

Originally Posted by xsperf

fixed.

lol jk, but i have no idea man, i would suggest emailing whoever you bought your 02 sims from or the actual company that made em

actually... it was 1137 bmw code, bank 2 sensor 1 i believe. also, the code is coming up for the front sensors, not for the rear ones, where i put the o2 sims. i don't know if installing the o2 sims had anything to do with the code though, but it's coming from the front sensors, not the sims. someone help, i don't want to get brand new cats and sensors just to diagnose this crap

**xsperf** · 03-14-2006, 11:00 PM

no no i was joking.. i guess your a little older than us kids

but 1337 = leet... haha

btw, try removing O2 sims and see if they pull a different code

**lecchilo** · 03-15-2006, 12:16 PM

bump...

**lecchilo** · 03-17-2006, 02:27 AM

komodo, did you remember yet, can you help me out ? thanks

**komodo** · 03-17-2006, 02:34 AM

Hey, sorry.

I remember I fought with my sim for almost 8 hours straight one day. There's 4 wires going to the O2 sensor: the ground, the accessory power, the heater power, and the signal return. After fooling with it, I ended up having to leave my o2 sensors on the pipe (drilled a hole for them, useless, but for storage), and leave the two heater wires going to the o2 sensor, rerouting the signal and ground to the sim. I double-tapped into the power wire, and cut the signal wire, routing the output from the sim straight to the ecu. Make sure you check voltages with a multimeter constantly, because we had issues getting the right connections.

This is how I finally had to end up wiring it:

That look similar to yours?

**lecchilo** · 03-17-2006, 03:20 AM

Quote:

Originally Posted by komodo

Hey, sorry.

I remember I fought with my sim for almost 8 hours straight one day. There's 4 wires going to the O2 sensor: the ground, the accessory power, the heater power, and the signal return. After fooling with it, I ended up having to leave my o2 sensors on the pipe (drilled a hole for them, useless, but for storage), and leave the two heater wires going to the o2 sensor, rerouting the signal and ground to the sim. I double-tapped into the power wire, and cut the signal wire, routing the output from the sim straight to the ecu. Make sure you check voltages with a multimeter constantly, because we had issues getting the right connections.

This is how I finally had to end up wiring it:

That look similar to yours?

i'm sorry i don't quite understand...
are those o2 sensors the rear or the front ones? my code is for the front sensor heater power....
i'll understand a bit more if you tell me if those are front or rear sensors...
if you can, go on aim, ivo328i is my sn

thanks a lot and sorry to bother you so much, i just really want this crap fixed

**komodo** · 03-17-2006, 03:25 AM

^^ OH! My bad. Yeah, I had my sims on my post o2 sensors because of the x-pipe getting rid of the cats.

Why are you running pre-o2 sims?

**lecchilo** · 03-17-2006, 03:28 AM

Quote:

Originally Posted by komodo

^^ OH! My bad. Yeah, I had my sims on my post o2 sensors because of the x-pipe getting rid of the cats.

Why are you running pre-o2 sims?

i'm not i was just trying to figure out the diagram...
i'm saying the code that i get from the CEL, is for the heater circuit for one of the front o2 sensors... so i'm wondering if that has anythign to do with the sims...
the diagram you drew is of the sims and the rear o2 sensors correct?? your front ones are just normally installed correct??

**komodo** · 03-17-2006, 09:42 AM

^^ Yep, front o2 sensors are untouched, sims installed in conjunction with post-cat o2 sensors.

**lecchilo** · 03-17-2006, 12:02 PM

Quote:

Originally Posted by komodo

^^ Yep, front o2 sensors are untouched, sims installed in conjunction with post-cat o2 sensors.

ok, now i kind of get it...
are the sims or the actual o2 sensors plugged into the o2 sensor harness? or are they just wired up without using any of the harnesses? please PM me and explain as good as possible, i'm not that great with wiring.

**komodo** · 03-17-2006, 08:06 PM

I'd rather not PM as not to leave any holes in case anyone else finds this thread in the future and has a similar issue.

In my diagram above where it says ECU, imagine that as the harness going under the car. I just took the harness that was going to the post-cat O2 sensors, and cut into the wires. I spiced the ground and signal wire (reporting oxygen content) to the sim, and left the other 2 wires plugged into the O2 sensor like normal.

So basically there are 4 wires in the harness. Two of them I cut and respliced, directing them instead to the sim (so the end on the o2 sensor is cut and dangling, and from the harness they're going straight to the sim). The other two wires for the heater are going straight from the ecu, through the harness, and to the O2 sensors like normal. Beyond that the only additional modification was the double-tap to power the sim. Try studying the diagram I posted again, and with this new descripition see if it makes more sense.

I hope I clarified that a bit, if not, let me know.

**lecchilo** · 03-18-2006, 03:23 AM

Quote:

Originally Posted by komodo

I'd rather not PM as not to leave any holes in case anyone else finds this thread in the future and has a similar issue.

In my diagram above where it says ECU, imagine that as the harness going under the car. I just took the harness that was going to the post-cat O2 sensors, and cut into the wires. I spiced the ground and signal wire (reporting oxygen content) to the sim, and left the other 2 wires plugged into the O2 sensor like normal.

So basically there are 4 wires in the harness. Two of them I cut and respliced, directing them instead to the sim (so the end on the o2 sensor is cut and dangling, and from the harness they're going straight to the sim). The other two wires for the heater are going straight from the ecu, through the harness, and to the O2 sensors like normal. Beyond that the only additional modification was the double-tap to power the sim. Try studying the diagram I posted again, and with this new descripition see if it makes more sense.

I hope I clarified that a bit, if not, let me know.

i think you clarified it much more... did you have the same problem as far as CEL and code is concerned and this solved it? also... just to clear this up a little more... you have the o2 sensors plugged into the harness, but then on the harness side you cut the 2 wires from each harness to connect them to the sims?? are the connectors from the sims just dangling with the 2 wires connected to them or what?
thanks again for trying to help, i really want to get rid of this cel.

**komodo** · 03-18-2006, 11:17 AM

^^ Nah, the sim has all 4 wires connected. I have a dual-sim, so the single box output a signal for both o2 sensors (see diagram, 2 signal out wires, one for each o2 sensor). The only wires "dangling" are the signal and ground wire coming from each O2 sensor.

**lecchilo** · 03-18-2006, 01:06 PM

Quote:

Originally Posted by komodo

^^ Nah, the sim has all 4 wires connected. I have a dual-sim, so the single box output a signal for both o2 sensors (see diagram, 2 signal out wires, one for each o2 sensor). The only wires "dangling" are the signal and ground wire coming from each O2 sensor.

oh ok. i have 2 o2 sims and each has a connector like the o2 sensor one at its end, so they're supposed to just plug into the harnesses.

what you're saying is that... of all the wires... all are connected except the signal and ground wire from each o2 sensor ?? so basically i can plug both my o2 sims into the harnesses, then from one o2 sensor, connect the heater power and heater ground to the wires on the harness, between the ecu and the harness, then do the same for the other side, while leaving the other 2 wires from the o2 sensors, signal and ground, not connected to anything ??
i feel really stupid not understanding any of this but want to make sure i fully understand before i do anything.
basically, tell me what i should do since i have 2 o2 sensor sims that have the same connector at the end...
last quesion... in your diagram, what do the grey dotted lines from ground and signal of each o2 sensor represent?? just air? haha
oh and here's my diagram... is this how it should be done...?
please correct anything on my diagram because then i will understand it better, since that is what i see on my car now...
(wire colors are arbitrary...i have yet to figure out which is which)