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Juan Crespo
Juan Crespo, Tech Trainer
Category: BMW
Satisfied Customers: 1526
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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My name is ***** ***** jam having a intermittent fault code

Customer Question

My name is ***** ***** jam having a intermittent fault code 281d on a 2004 330i I've replaced the alternator 4 times thinking that was it and the last time with a oem one. I can't find any info on how to t/s this code . If i disconnect this
JA: Thanks. Can you give me any more details about your issue?
Customer: yes i was saying if i disconnect the connector from the alt i immediately get code 281c bsd interface so i know the wire from the alt to the dme is good.just don't know why i would be getting this intermittent battery charge lt on when its charging good 14.3 volts with the light on
JA: OK got it. Last thing — BMW Mechanics generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: BMW
Customer: replied 1 year ago.
more info on what I've done already had charging system checked at just auto zone it tested fine. Battery also checked tested good . replaced the drive belts checked tensioner looked good . checked engine strap was corroded cleaned it. just can't find how to troubleshoot this intermittent code 281d BSD generator signal.
Expert:  Juan Crespo replied 1 year ago.

Welcome, my name is***** am a verified expert automobile technician. I, and all others like me are neither employees nor agents of Just Answer. We are independent service providers using the Site to sell our Expert knowledge to customers. I do my best to provide EXCELLENT 5 STAR service, please let me know what you need from me so you’re satisfied with my efforts and reward me with a Positive Rating.

Most likely cause is a Green/Brown wire broken under the insulation making a good connection intermittently - could mislead you into thinking it's good when the DME flags a code after you disconnect it. A more accurate way would be to leave it connected then wiggle it and see if it then flags the code. To confirm this, you could run a second wire, in fact creating a redundant circuit. You'll know you've found the cause if the issue goes away.

Please let me know if that helps.

Best Regards.

Customer: replied 1 year ago.
I have verified this wire is good I did a continuity test from the alt connector tk the dme while shaking wire had no faults .do you know what is the bmw diagnostic code troubleshooting procedure
Expert:  Juan Crespo replied 1 year ago.

Which alternator, Bosch or Valeo?

Expert:  Juan Crespo replied 1 year ago.

Oops, forgot to ask the most important question; what are you using to communicate with the DME, ISTA-d or O.S.S.?

Customer: replied 1 year ago.
It's a Bosch and I just have launch Bluetooth scanner . With the code 281d intermittently
Expert:  Juan Crespo replied 1 year ago.

I'm afraid all I've got on BMW procedures for this kind of issue is based on data obtained through either ISTAd or OSS (see attached graphic). I just can't see how that's going to help you if you don't have access to either software. Would you like me to opt out and re-open the question to the field to see if another expert has a way of working with the tool you do have? - optionally you could just ask customer service for a refund.

Best Regards.

Customer: replied 1 year ago.
it looks like at this point I would really need the software to troubleshoot this .one other question I saw in the attachmentl you sent it said that this code will not turn on the mil is that the same light as the battery light.thanks for your input