Tech > Tech Help

2019 FXS precharge failure, help wanted

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Tymck7:
TL:DR - why would a 2019 FXS fail to precharge/close the contactor, and how do I fix this?

Long version:
I put a gen 4 size 6 controller and a 75-7 motor on my 2019 FXS and have been fiddling with the config files in DVT on the controller to get it to run right (with some helpful guidance).  I tried a new firmware and .dcf file on the controller last week, and immediately after what I thought was a successful update to the controller (DVT said the .dld load was complete and then I uploaded the .dcf without any abnormal occurrences), the bike ceased being able to precharge and hence, won't close the contactor.  Plugging into the onboard charger will not charge either.

I subsequently switched to my stock gen4 size4 controller with essentially stock config settings, and the first time I keyed on the bike, it precharged and the contactor closed!  After a few seconds though of me trying to adjust the settings in DVT on my size 4 controller, DVT said the controller had disconnected, and all subsequent attempts to key on the bike fail to precharge or close the contactor, with either controller.  I also am consistently getting errors 25, 27, 48 and 49 on the dash. 

When keyed on, the bike initially would blink the green circle on the dash, then add a constant check engine light, sit there for a while blinking the green light trying to precharge, and then give up and sleep after 15 seconds or so.  However, after trying that a few times, the bike has started to sleep much more quickly, after ~5 seconds.  I cannot access the bike/battery logs, as the bike sleeps way too quickly to extract anything over the app.

Checked all three high voltage fuses (but not the 100A one) and they are good.  Reset the BMS, no improvement.  I'm thinking about resetting the MBB as the next step.

Few questions:
I ordered a TTL to USB and a OBD2 connector to hopefully communicate with the MBB as per the unofficial manual (https://zeromanual.com/wiki/How_to_build_a_cable_to_access_the_MBB).  Will the MBB respond in this situation? 

Will resetting the MBB mess anything else important up?

Any other ideas?

Just want to get my bike up and running again in some form. 
Thanks!!

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