MPVI2 Protocol Fail for E38

attempted to read a customers LS Swap 2010 Silverado 5.3 E38 and I keep getting Protocol Failure message. I attempted to hook up to my personal truck E67 ECU and had not issues, worked as advertised. I also swapped out the E38 ECU with a known good spare and got the same failure message. I attempted the resync and it didn't fix anything.

How do manually push a firmware update?
Could it be a wiring issue with the LS swap truck? only needs constant power to PSI conversions harness (starter wires) and cranking power, easily found in fuse panel. So wiring is straight forward and not a hack job, all professionally done with good products.

I submitted a ticket (228943) but highly doubt its my interface as it reads fine on one vehicle and not another. Anyone else run into a vehicle specific issue not allowing hook up?

Sounds like a wiring issue with the vehicle to me.

Thanks for the reply, did some troubleshooting tonight and eliminated any wiring issues. The PSI Harness conversion simply applies 12V Constant power to the ECU via the starter lug, one additional power wire while in run position and cranking, simply put constant 12V power to it for troubleshoot purposes. Still getting the Detect Protocol Failure message! Super frustrating

Is there power at the OBD2 plug though?

Yes just confirmed 12V at the OBD2 port. I have dumb down the wiring so it’s absolutely simplistic for troubleshooting and I’m still getting the Detect Protocol Failure message. HPTuners sent an email saying it’s the vehicle not the interface. Well now I’m confused.

Try reading via bench harness.

Here's the thing, you were able to read a GMPP ecm(E67) without issue using our product so this tells us our product is functioning properly on CAN based ecm's

E38 is a CAN based ecm so you are having trouble with 2 E38 CAN based ecm's which we've already determined our product is functioning properly on CAN based ecm's even by your own accord which leads us to believe its either a wiring or an ecm issue on your end.

Now, you've tried 2 different ecm's so the odds of both of those ecm's having issues is VERY slim so we can narrow it to to probably a 99% chance its the wiring 1% chance of it being related to BOTH of the ecm's you tested.

Soooooooo pulled all connectors and reseated them, but the culprit was the 6l90e plug��*♂️, good to go! Thanks for the help and I always put the fix for others.

Glad to hear it always happy to help :)