Ecm communication

Having a bit of an issue here. I was able to read tune file alter tune file write changes and start vehicle while scanning. After about 30 seconds scanner lost communication and I can?t seem to regain it. My little bs 50$ scanner connects reads and clear codes and does everything it?s supposed to do but my hptuner device just will not connect. Can?t load any scan data as I wasn?t able to collect any. I can load the tune file if it may be of some use. I have confirmed battery volts and grounds are good at obd connector and data wire must be functioning for my other scanner to operate. I have restarted my laptop and resynced my device as well.

Vehicle MMY?

Really sounds more like a scanner/cable/computer issue to me. Can you read the file that is now loaded back out?

Vehicle is 2002 trans am ws6 has a built 5.7 but original ecm wasn?t there. Ordered a replacement online and it?s a 99 sierra 5.3 ecm but has been flashed for the 02 settings and tune. It allowed me to go in and make some changes and log the car a few times then all of a sudden my hptuners device just won?t connect. When I plug it in it lights up for power but nothing else and as I said before the other scanner I have will connect and scan no problem.

No it won?t let me do anything through hptuners now. I have checked my device cable and computer by connecting to another vehicle and seems to work just fine which has left me completely baffled. It can?t be the car because my other scan tool works just fine. Can?t be my device cable or computer because it works fine on other vehicles but when I combine the two it won?t work at all 🤦*♂️

As a test do you have another vehicle you can hook the MPVI to? Preferably another Gen 3? That would verify an MPVI issue or a vehicle issue.

02 Fbodys never have issues because of aftermarket radios. Does by any chance have an aftermarket alarm or remote start that taps into the purple wire on the ALDL connector?

Already tested mpvi on another gen3 it?s dbw but still gen 3. No aftermarket radio or alarm but has factory keyless entry setup. Gonna get a bench tune harness and try that next.

First thing you need to do is connect to the vehicle and with the key on collect an infolog. That will let us know if it is or isn't actually connecting to the vehicle. Read up on how to collect and save an infolog. Post it here. You're going to need an infolog anyway if you end up contacting tech support about this. That's the first thing they'll ask for. That and the dat debug file.

Once you have that post it here.

I would still look under the dash at the ALDL wiring and make sure there is no monkey business going on with the purple data wire. Although with the MPVI3 there in no telling what the problem might be.