Electrical Issues?

shadowx360 · 06-01-2013, 01:12 AM

Hi, I've been having some electrical issues with my 2006 330i lately. It started when my car wouldn't crank one day. Checked battery, voltage was 10.6 V. Charged it externally to 12.6 V and got the battery changed to a 700 CCA battery from Advance Auto Parts since the car is about time for a battery change. Alternator tested fine at 13.6-13.9V

During the next 3 weeks, my car wouldn't start twice, both times due to voltage dropping to around 11.6V after not using my car for two days. After I got my OBD cable, I noticed the car was throwing an error code, IBS communications issue. Apparently my IBS module was unplugged. Plugged it back in. Coded the CAS/FRM modules for the new battery specs and then also registered a new battery to the IBS. I know from the specs that the IBS is supposed to send a kill signal to the DME when battery gets low to cut all power, but even after I did all of this, I often come out in the morning and my car's battery is around 12.00 V after leaving it overnight. This seems to be a very high draw to me and I've been too scared to leave it off for more than two days to see if it drops any further. The IBS is supposed to send the kill signal but I'm not sure if it does or if the kill signal actually stops the power draw.

A second related issue, when I crank the car, all the interior/gauge lights and radio shut off and I can hear the starter pause as if it's stuck or out of juice, leading to very rough starts.

Any advice on this? On a maybe-related sidenote, I'm getting an SOS Systems Failure error, which is most likely a failing TCU module (I also can't connect to the TCU when I try to code it, so I'm guessing it's gone bad). I'm not aware of any relationship between the TCU and power draw though.

PINeely · 06-01-2013, 05:13 PM

Has the battery been registered? Unfortunately you can't just drop in a new one and charge it up... the car stores data on battery usage and voltages and cannot apply the correct voltage with a new battery until that old data is removed and the battery registered.

shadowx360 · 06-01-2013, 10:45 PM

Yep, I registered using Toolset 32 and also coded it using NCSExpert.

johngrossi · 06-09-2013, 02:04 PM

Pull your negative battery cable and put a ammeter in series and monitor current draw. IIRC acceptable current draw should be no more than 150ma. Try unplugging the ibs and tcu and see if you observe a change in parasitic draw.

06-01-2013, 01:12 AM	#1
shadowx360 Private First Class 41 Rep 146 Posts Drives: BMW 340i Join Date: Apr 2013 Location: United States iTrader: (0)	Electrical Issues? Hi, I've been having some electrical issues with my 2006 330i lately. It started when my car wouldn't crank one day. Checked battery, voltage was 10.6 V. Charged it externally to 12.6 V and got the battery changed to a 700 CCA battery from Advance Auto Parts since the car is about time for a battery change. Alternator tested fine at 13.6-13.9V During the next 3 weeks, my car wouldn't start twice, both times due to voltage dropping to around 11.6V after not using my car for two days. After I got my OBD cable, I noticed the car was throwing an error code, IBS communications issue. Apparently my IBS module was unplugged. Plugged it back in. Coded the CAS/FRM modules for the new battery specs and then also registered a new battery to the IBS. I know from the specs that the IBS is supposed to send a kill signal to the DME when battery gets low to cut all power, but even after I did all of this, I often come out in the morning and my car's battery is around 12.00 V after leaving it overnight. This seems to be a very high draw to me and I've been too scared to leave it off for more than two days to see if it drops any further. The IBS is supposed to send the kill signal but I'm not sure if it does or if the kill signal actually stops the power draw. A second related issue, when I crank the car, all the interior/gauge lights and radio shut off and I can hear the starter pause as if it's stuck or out of juice, leading to very rough starts. Any advice on this? On a maybe-related sidenote, I'm getting an SOS Systems Failure error, which is most likely a failing TCU module (I also can't connect to the TCU when I try to code it, so I'm guessing it's gone bad). I'm not aware of any relationship between the TCU and power draw though.
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06-01-2013, 05:13 PM	#2
PINeely Lieutenant Colonel 1086 Rep 1,912 Posts Drives: 2013 535i, 2015 Tundra 1794 Join Date: Jul 2009 Location: Jackson, MS iTrader: (2)	Has the battery been registered? Unfortunately you can't just drop in a new one and charge it up... the car stores data on battery usage and voltages and cannot apply the correct voltage with a new battery until that old data is removed and the battery registered.
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06-01-2013, 10:45 PM	#3
shadowx360 Private First Class 41 Rep 146 Posts Drives: BMW 340i Join Date: Apr 2013 Location: United States iTrader: (0)	Yep, I registered using Toolset 32 and also coded it using NCSExpert.
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06-09-2013, 02:04 PM	#4
johngrossi Second Lieutenant 9 Rep 234 Posts Drives: 2011 135i e82 Join Date: May 2013 Location: Illinois iTrader: (1)	Pull your negative battery cable and put a ammeter in series and monitor current draw. IIRC acceptable current draw should be no more than 150ma. Try unplugging the ibs and tcu and see if you observe a change in parasitic draw.
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