2020 3500 dash disco

[JustAnotherDude]

Just picked up a 2020 3500 6.7 w/Aisin. Dash intermittently turns into a Christmas tree with all systems going offline and ding ding ding. Happens randomly. Shop had numerous ABS "lost communication" codes with a few TCM "lost communication" codes. Any chance this is similar to the ABS/HCU issues 2017/2018's were having? Anyone have schematics showing where the ABS and TCM can-bus connections are?

 

[mtnrider]

Are you having issues starting as well? Have you load tested the batteries?

./

 

[JustAnotherDude]

No starting issues. Shop had same thought and would have checked that though I did not verify.

 

[mtnrider]

No starting issues. Shop had same thought and would have checked that though I did not verify.

Not all shops are created equal.... I would ask them directly if they load tested them (individually), and to be clear checking the voltage level is Not an adequate test, they need to be load tested.

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[2003F350]

With multiple modules throwing 'lost communications' codes, I would be inspecting wiring harnesses and connectors if the batteries are checking out good. Bad grounds will cause issues like this as well. If it were just one module I would suspect the module, but multiple usually means wiring.

 

[JustAnotherDude]

That's what I've been leaning towards, connections. Not looking forward to trying to just FIND all the damn wires and grounds.