281 c & 281 d

**JCF076** · 04-22-2019, 11:53 AM

Good morning to you all,

I have an issue that I have been having for a while now. So my battery is not charging. I've replaced my battery 3 times within this year alone and I have replaced the alternator as well. My 2005 BMW 325i Sedan with an M56 engine struggles to start. I have scanned the car and get these two codes. 281-C bit serial data interface signal and 281-D DME. I have searched and searched and still i have no clear answer on what the problem is and how it can be fixed. I've read multiple posts on here and hopefully you guys can be my saviors.

Thanks to all in advance.

**dworthy** · 04-23-2019, 05:03 AM

Welcome to the Forum!

What system are you using to scan the car? What ECU are you scanning?

As for the codes, did you clear them, and they come right back?

Have you done a voltage drop to see how much the starter is pulling?

Now when you say it struggles to start:

1) Is that from a slow spinning starter?
2) Does it take several rotations of the motor before starting?
3) Does the car even start?

**MarcoZandrini** · 04-23-2019, 07:25 AM

Three new batteries in a year if very definitely not right. Are the batteries losing their charge when the car sits? Have you checked to see if the car has a parasitic drain? A parasitic drain means the car is using too much current (amps) when it’s off. Typically, an E46’s electrical system will draw about 50 milliamperes (0.05 amps) when it’s shut off and asleep. Yes, these cars go into a sleep mode after about 15 minutes after you’ve exited the car. How many miles do you typically drive the car in a week? What brand is the new alternator? Is it new or rebuilt?

**JCF076** · 04-30-2019, 08:38 PM

@dworthy I had scanned the car becuase a check engine light came on. The code was for the secondary air injection valve. But once I cleared that code the check engine light didnt come on. Once I scanned it again to see if the valve code was there the 281C and 281 D codes came up. The Check engine doesnt light up though. As for the scanner I am using a Creator C110 V4.4 Auto OBDII Fault Code Reader BMW/Mini Diagnostic Scan Tool. The does not start anymore. It wants to though. Before It went out It would struggle but after like 4 spins it would turn on.

**JCF076** · 04-30-2019, 08:46 PM

@MarcoZandrini I haven't done a parasitic drain test? I would do so. I typically drive it around 20 miles per week. I mainly use it for school transportation. It's a 150 amp duralsat alternator that i bought from autozone. It is a remanufactured alternator.