Loss of Comms BCM codes
#1
07-30-2017, 11:10 PM
Loss of Comms BCM codes
I wanted to share my ordeal with you all so maybe someone will not have to deal with the frustration I dealt with trying to figure this nightmare out. Ok, it started with bcm codes u0001 (canbus fault), u0140 (loss of comms with bcm), u0141 (loss of comms lhcm), u0142 (loss of comms rhcm) and u0156 (loss of comms with speedo). Of course the check engine light would come on and go out . This was happening over the last year and I just couldnt figure out what it was. So one day , thinking it had to be in the apehanger bars i installed about 3 years ago I removed all wiring from the bars and found nothing wrong. Checked the left and right hand control switches and wiring and found nothing. Checked all connectors relating to codes in the fairing and under the seat. Nothing. So a few months later I decided to tackle it again because I was on vacation and bored with nothing to do. I removed the tank and checked the wiring under the tank in the wire way. They all looked good. Finally, I decided to start the bike . While idling I turned the bars left and right to the stops. Low and behold, the codes came back. Found about 5 wires pinched from flexing all the time at the right side neck area. I could literally pull the wires apart . They were broken inside the insulation and barely making contact. A classic intermittent nightmare was exposed finally. I was so happy. I spliced the wires back together and the bike has been running code free for a couple months. My frustration with the MoCo is enormous as they used the smallest wire gauge they could get away with. These wires are so fragile and easy to break. Shame on them for doing this. Ok Im finally done venting. If you reached this sentence, thanks for listening. Hope to help someone out someday.
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#2
07-31-2017, 04:37 AM
#3
08-01-2017, 12:34 AM
#4
01-29-2019, 04:42 AM
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Location: Paris tx
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I wanted to share my ordeal with you all so maybe someone will not have to deal with the frustration I dealt with trying to figure this nightmare out. Ok, it started with bcm codes u0001 (canbus fault), u0140 (loss of comms with bcm), u0141 (loss of comms lhcm), u0142 (loss of comms rhcm) and u0156 (loss of comms with speedo). Of course the check engine light would come on and go out . This was happening over the last year and I just couldnt figure out what it was. So one day , thinking it had to be in the apehanger bars i installed about 3 years ago I removed all wiring from the bars and found nothing wrong. Checked the left and right hand control switches and wiring and found nothing. Checked all connectors relating to codes in the fairing and under the seat. Nothing. So a few months later I decided to tackle it again because I was on vacation and bored with nothing to do. I removed the tank and checked the wiring under the tank in the wire way. They all looked good. Finally, I decided to start the bike . While idling I turned the bars left and right to the stops. Low and behold, the codes came back. Found about 5 wires pinched from flexing all the time at the right side neck area. I could literally pull the wires apart . They were broken inside the insulation and barely making contact. A classic intermittent nightmare was exposed finally. I was so happy. I spliced the wires back together and the bike has been running code free for a couple months. My frustration with the MoCo is enormous as they used the smallest wire gauge they could get away with. These wires are so fragile and easy to break. Shame on them for doing this. Ok Im finally done venting. If you reached this sentence, thanks for listening. Hope to help someone out someday.
#5
01-29-2019, 12:38 PM
Cruiser
Same kind of problem I had but the problem was actually in the connectors. I put different bars on. Removed the wires from the connectors and then re-installed them. Everything looked good but I was getting an intermittent trouble. After about 30 hours I finally traced it to loose connections within the connectors. the new M8 connectors are a little smaller than the older connectors and don't seem to support the wires from movement. Nothing broke, just not making a good connection on two of the wires. Pulled them out and checked them and wires and everything was good. Put them back in and connected up, boom, trouble. I cut the wires out of the connectors and re-spliced and troubles gone for good. When I cut the connectors off I verified no broken wires inside the sheath. PITA
#6
07-21-2019, 03:54 PM
Stage IV
Join Date: Jan 2016
Location: Maine
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Thank you so much.. similar problems on my 2017 Street glide
This stuff is amazing when you have to strip off all the other wiring harness.
And I also put a video on YouTube
And I also put a video on YouTube
And I also put a video on YouTube
I wanted to share my ordeal with you all so maybe someone will not have to deal with the frustration I dealt with trying to figure this nightmare out. Ok, it started with bcm codes u0001 (canbus fault), u0140 (loss of comms with bcm), u0141 (loss of comms lhcm), u0142 (loss of comms rhcm) and u0156 (loss of comms with speedo). Of course the check engine light would come on and go out . This was happening over the last year and I just couldnt figure out what it was. So one day , thinking it had to be in the apehanger bars i installed about 3 years ago I removed all wiring from the bars and found nothing wrong. Checked the left and right hand control switches and wiring and found nothing. Checked all connectors relating to codes in the fairing and under the seat. Nothing. So a few months later I decided to tackle it again because I was on vacation and bored with nothing to do. I removed the tank and checked the wiring under the tank in the wire way. They all looked good. Finally, I decided to start the bike . While idling I turned the bars left and right to the stops. Low and behold, the codes came back. Found about 5 wires pinched from flexing all the time at the right side neck area. I could literally pull the wires apart . They were broken inside the insulation and barely making contact. A classic intermittent nightmare was exposed finally. I was so happy. I spliced the wires back together and the bike has been running code free for a couple months. My frustration with the MoCo is enormous as they used the smallest wire gauge they could get away with. These wires are so fragile and easy to break. Shame on them for doing this. Ok Im finally done venting. If you reached this sentence, thanks for listening. Hope to help someone out someday.
Last edited by Randy Redman; 07-21-2019 at 03:59 PM.
#7
07-23-2019, 06:01 PM
Seasoned HDF Member
Trending Topics
#8
03-27-2020, 03:30 AM
#9
06-17-2020, 01:52 PM
Stage I
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#10
04-29-2021, 05:34 PM
Cruiser
I just had bars installed on my 2020 Street Glide Special and I'm getting a bcm code U0125. The bike runs great though. I've been researching it and this seems to be an uncommon code. Supposedly a loss of comms code. It won't clear and comes right back. Anyone know anything about this? Thanks
