Warning: Autel MD802 + Ultragauge (UG) = ???

I recently received an OBDII 'splitter' cable that I hoped would allow me to keep my UG connected while checking for codes, doing some 'live data' recording & investigating other operation options of my MD802.

Unfortunately, the MD802 was unable to determine the ECU type & returned some weird codes when both the UG & MD802 were connected to the OBDII Port. I unplugged the UG & the MD802 operated OK, detecting the correct Sprinter ECU.

So, either bus loading, or conflicting communication between the UG, the MD802 & the ECU caused problems. Beware!!

OTOH, the 'splitter' cable connector is low profile, so I was able to return the MB socket to its original position , remove the black OBDII socket cover & have the UG connected. This makes it easier for me to disconnect the UG & connect the MD802.
(To get a clean installation of the UG, I had unlatched the OBDII socket, connected the UG & tucked the connection in behind the panel just under the light switch. This meant that I had to remove the panel every time I needed to connect the MD802.)

I've used a splitter with mixed results to sniff the k-line for transmission and ecm. I've read somewhere that you can not use a splitter.

I get better results when tapping into the k-line (no splitter cable).

Edit, there could also be a conflict of tester address. Both the Autel and UG may have the same address. I was using (not at the same time) two testers; DAD and ScanGauge. ScanGauge uses address F1 while DAD uses F3.