U0100 Lost Communication With ECM/PCM "A" ?

crazyinp · 09-22-2012, 05:19 PM

I was running some errants today and was doing frequent stops. I pressed the start/stop button and the car started for few seconds then suddenly died. Engine Malfunction Power reduce came on. I tried to start the it again without luck. The engine kept trying to start for 5-6secs without any luck, I had to press the start/stop again to stop it. I let the car sit for 20secs and tried again. This time it started without any issues with SES on the dash. When I got home I read the ECU with the following error code -
U0100 Lost Communication With ECM/PCM "A". I didn't have any issues and the car ran just fine. What do you think might have cause it?
I do have JBD on default setting.

GreekboyD · 09-22-2012, 05:52 PM

Air flow sensor?

Vreimann · 09-22-2012, 06:44 PM

Do you have the convenience package for your car?

crazyinp · 09-22-2012, 07:31 PM

Quote:

Originally Posted by GreekboyD

Air flow sensor?

Don't see how air flow should be related.

Quote:

Originally Posted by Vreimann

Do you have the convenience package for your car?

No convenience package. Car seems fine now. No difference.

FRMTL2_335i · 03-13-2016, 03:35 PM

Any updates on this? Did it happen again?

MykD · 07-31-2016, 11:19 AM

I'd love to know what was up with this. My 07 328i is throwing that code after valvetronic motor replacement and won't start.

Mik325tds · 08-01-2016, 06:21 PM

Those faults are hard to find. Could be a bad connection or corrosion on CAN connections. It could also be a software bug. U0100 also is set if the application layer CRC is incorrect. Unfortunately, U0100 is a collector DTC for many different faults. Without subfault description it's a needle in a haystack. Try to read "is memory" in ediabas.

09-22-2012, 05:19 PM	#1
crazyinp Major 299 Rep 1,246 Posts Drives: BMW Join Date: Jul 2011 Location: Bay Area iTrader: (5) Garage List 2022 BMW X5e [0.00] 2023 BMW X5M [0.00]	U0100 Lost Communication With ECM/PCM "A" ? I was running some errants today and was doing frequent stops. I pressed the start/stop button and the car started for few seconds then suddenly died. Engine Malfunction Power reduce came on. I tried to start the it again without luck. The engine kept trying to start for 5-6secs without any luck, I had to press the start/stop again to stop it. I let the car sit for 20secs and tried again. This time it started without any issues with SES on the dash. When I got home I read the ECU with the following error code - U0100 Lost Communication With ECM/PCM "A". I didn't have any issues and the car ran just fine. What do you think might have cause it? I do have JBD on default setting.
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09-22-2012, 05:52 PM	#2
GreekboyD Brigadier General 411 Rep 3,049 Posts Drives: 2009 BMW 335d Join Date: Jan 2012 Location: Toronto, ON, Canada iTrader: (0) Garage List 2009 BMW 335d [8.00]	Air flow sensor?
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09-22-2012, 06:44 PM	#3
Vreimann Private First Class 10 Rep 199 Posts Drives: N/A Join Date: Mar 2012 Location: N/A iTrader: (0)	Do you have the convenience package for your car? __________________ 2011 335D
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03-13-2016, 03:35 PM	#5
FRMTL2_335i Major 76 Rep 1,071 Posts Drives: E92 335i Join Date: Mar 2013 Location: ohio iTrader: (1)	Any updates on this? Did it happen again?
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07-31-2016, 11:19 AM	#6
MykD New Member 2 Rep 7 Posts Drives: 07 328i & a Benz E300 Join Date: Mar 2014 Location: West Bradenton, FL iTrader: (0)	I'd love to know what was up with this. My 07 328i is throwing that code after valvetronic motor replacement and won't start.
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08-01-2016, 06:21 PM	#7
Mik325tds Major 807 Rep 1,191 Posts Drives: 335d M-Sport Join Date: Jul 2014 Location: Greater Detroit iTrader: (0)	Those faults are hard to find. Could be a bad connection or corrosion on CAN connections. It could also be a software bug. U0100 also is set if the application layer CRC is incorrect. Unfortunately, U0100 is a collector DTC for many different faults. Without subfault description it's a needle in a haystack. Try to read "is memory" in ediabas.
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