2017 possible transmission issues? Help appreciated.

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chevyboltbb

New member
Joined
Aug 29, 2024
Messages
1
Hey everyone!

My 2017 is giving me some issues; just in time for back-to-school season :(
Any help would be amazing in diagnosing this sucker.

Here's what's going on:
  1. While driving in either L or D the transmission feels as if it disengages for a moment, then I get a couple lights thrown: Antilock Brake System (ABS) Warning Light and StabiliTrak Off.
  2. I am also shown a couple warnings on the center dash that I'm able to "Dismiss." Here they are: Transmission, Steering Assist is Reduced Drive with Care, and Park Assist Off.
  3. A couple times I've also had these lights thrown: Lane Keep Assist (LKA) Light, and Vehicle Ahead Indicator (mind you there is not a vehicle ahead to trigger this).
I also have a couple standard OBD2 codes being thrown:

  1. U0077 - Network Electrical - Reserved by Document 4
  2. P25C9 - This Generic Definition is not available
I've attached a few images for reference!
 

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Hey everyone!

My 2017 is giving me some issues; just in time for back-to-school season :(
Any help would be amazing in diagnosing this sucker.

Here's what's going on:
  1. While driving in either L or D the transmission feels as if it disengages for a moment, then I get a couple lights thrown: Antilock Brake System (ABS) Warning Light and StabiliTrak Off.
  2. I am also shown a couple warnings on the center dash that I'm able to "Dismiss." Here they are: Transmission, Steering Assist is Reduced Drive with Care, and Park Assist Off.
  3. A couple times I've also had these lights thrown: Lane Keep Assist (LKA) Light, and Vehicle Ahead Indicator (mind you there is not a vehicle ahead to trigger this).
I also have a couple standard OBD2 codes being thrown:

  1. U0077 - Network Electrical - Reserved by Document 4
  2. P25C9 - This Generic Definition is not available
I've attached a few images for reference!
Your 2017 is throwing a fit right before back-to-school season, classic timing! The issues with the transmission and those warning lights seem like they could be connected. Have you checked in with a mechanic or tried reading the OBD2 codes for more clues?
 
The. P25C9 code appears relates to the brake system control module from what I can gather from an Internet search. The U0077 code appears to be bus ecpansion module lost CAN bus communication,

My suspicion is that the U0077 code is probably caused by the other module failing. StabiliTrak, lane keep, and ABS are all braking related. There could be an electrical failure in the model or a loose connection. The most basic thing to try is to clean and re-seat all of the connectors on the brake control module. I’ve had pretty good luck removing corrosion connector pins with Caig Labs D-100 spray. That Is strictly a cleaner. Caig Labs also makes DP-5 whixh is a contact preservative spray.

I’d recommend finding a mechanic who has an advanced OBD-II scan tool such as an Autel which csn do an individual module deep scan. I’ve got the Harbor Freight Zurich scan tool which a relabeled Innova bidirectional scan tool. I’m not sure the Zurich scanner is advanced enough for your issue, but I was able to drill down into to power train control module 2 on my 2017 Bolt to find one side of the contactor in the battery was stuck in the on position. Without the fairly decent scan tool I just got the dashboard MIL lit and a generic code. The battery contactor was covered under the power train warranty. It was a free fix at the dealer even though the car was six years old at the time.
 
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