HELP: need to find out what this wire goes too

vinnydot335i · 07-10-2017, 06:16 PM

Hello everyone. I recently picked up a low mileage 135i to take place of my 07' 335i. I didnt know how to drive stick but picked it up very fast over the weekend. Last night i was out just practicing and decided to give the car a little throttle, as soon as i slowly accelerated in 3rd gear i got hit with half a check engine light. I didnt have time to scan the car myself when i got home so i had my dad do it for me while i was at work today and it read a turbo charger boost sensor code with his snap on scanner.(PO238) Than i scanned it when i got home with jb4 and got a 3100 code.

As my dad was inspecting the car while i was working he found this grey wire laying on the exhaust manifold and it was burnt. Is it possible that this wire is shorting out on the exhaust manifold causing my issues? Even if not can someone please tell me what this wire leads too? Im sure it burning cant be any good.
Thank you for all of your help in advance guys, this is making me sick thinking i bought a lemon to replace a perfectly normal car...

drunkenup · 07-10-2017, 06:23 PM

That's an 02 sensor. Judging by routing its for the rear turbo, precat

IllSic_Design · 07-10-2017, 07:15 PM

Grey wire is your rear turbo pre-cat o2 sensor, black is front turbo o2. I doubt that would be causing the code you stated.

3100 code can be cause by quite a few different things. Broken/cracked vacuum lines, worn turbo waste gates, bad turbo boost solenoids, etc... Do a search for more info

vinnydot335i · 07-11-2017, 05:36 PM

thank you guys.. how would i go about diagnosing a bad solenoid? ive done the basics as far as checking the vaccum lines, canisters, charge pipe, intercooler connections etc. so far havent found anything out of the ordinary besides that o2 sensor wire which i believe has nothing to do with this 3100/pO238 codes im getting.

ken335AZ · 07-11-2017, 07:21 PM

Quote:

Originally Posted by vinnydot335i

thank you guys.. how would i go about diagnosing a bad solenoid? ive done the basics as far as checking the vaccum lines, canisters, charge pipe, intercooler connections etc. so far havent found anything out of the ordinary besides that o2 sensor wire which i believe has nothing to do with this 3100/pO238 codes im getting.

Hey, providing a link cause so you can read through it, but it may be helpful in the step by step diagnosis.
https://www.yourmechanic.com/article...by-jay-safford

07-10-2017, 06:16 PM	#1
vinnydot335i New Member 0 Rep 15 Posts Drives: 2007 e90 335i Join Date: Jun 2016 Location: port Chester New York iTrader: (0)	HELP: need to find out what this wire goes too Hello everyone. I recently picked up a low mileage 135i to take place of my 07' 335i. I didnt know how to drive stick but picked it up very fast over the weekend. Last night i was out just practicing and decided to give the car a little throttle, as soon as i slowly accelerated in 3rd gear i got hit with half a check engine light. I didnt have time to scan the car myself when i got home so i had my dad do it for me while i was at work today and it read a turbo charger boost sensor code with his snap on scanner.(PO238) Than i scanned it when i got home with jb4 and got a 3100 code. As my dad was inspecting the car while i was working he found this grey wire laying on the exhaust manifold and it was burnt. Is it possible that this wire is shorting out on the exhaust manifold causing my issues? Even if not can someone please tell me what this wire leads too? Im sure it burning cant be any good. Thank you for all of your help in advance guys, this is making me sick thinking i bought a lemon to replace a perfectly normal car... Attached Images
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07-10-2017, 06:23 PM	#2
drunkenup Captain 215 Rep 989 Posts Drives: 2009 135i, 2021 F150 Join Date: Sep 2013 Location: NJ iTrader: (1)	That's an 02 sensor. Judging by routing its for the rear turbo, precat __________________ MHD \| BMS \| VRSF \| APEX \| RECARO \| TC Kline \| BERK \| Turner Motorsport \| Eibach \| BMW Performance
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07-10-2017, 07:15 PM	#3
IllSic_Design Colonel 2124 Rep 2,758 Posts Drives: 09 E92 335i Join Date: Jun 2016 Location: Northern California iTrader: (1)	Grey wire is your rear turbo pre-cat o2 sensor, black is front turbo o2. I doubt that would be causing the code you stated. 3100 code can be cause by quite a few different things. Broken/cracked vacuum lines, worn turbo waste gates, bad turbo boost solenoids, etc... Do a search for more info
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07-11-2017, 05:36 PM	#4
vinnydot335i New Member 0 Rep 15 Posts Drives: 2007 e90 335i Join Date: Jun 2016 Location: port Chester New York iTrader: (0)	thank you guys.. how would i go about diagnosing a bad solenoid? ive done the basics as far as checking the vaccum lines, canisters, charge pipe, intercooler connections etc. so far havent found anything out of the ordinary besides that o2 sensor wire which i believe has nothing to do with this 3100/pO238 codes im getting.
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