Inline speedo calibrator - Check Engine light

[rainadog23]

I have a 2019 Silverado RST with 6in lift with 35in nittos and have hypertech inline speedo. I have gone through 6 inline speedo's thinking they were the calibrators fault. I would be on cruise and it would malfunciton droping from 65 mph to 55 mph and jump back and forth. Once day it was parked and stared the engine and my check engine light came on along with low oil pressure. I had to take the inline speedo out to get it the truck to work properly. All this time I kept thinking it was the inline speedo but last night I came out to the truck and my parking brake was engaged. This happened to me twice yesterday and finally a check engine light came on. Ran the codes and got P0700 (Transmission Control System), P25A2, U0073 (Control Module Communication Bus A Off), U0101(Lost communication with Transmission control module) , U0129 (Lost communication with brake system control module), U2413, P25A2.

 

This morning I check and the check engine light is now off. I have 6500 miles but since 3000 miles some wacky things have been happening. Does anyone have any ideas? What do I tell the dealership if the check engine light is now off?

 

Thanks

[ict_wildcat]

Did you ever get to the bottom of this?  I know it's been a while since you posted.  I'm running an inline speedo calibrator as well (rough country, not hypertech) and all has been fine until a CEL this morning with diagnostic code U0129.  Curious what you ended up doing.  Thanks!