The Edge is the only thing that screws up. The Smarty, and everything else works flawlessly. Anybody familiar with Smarty knows if there is any issue (even with batteries) it can deal you fits. My mechanics Snap-on scanner, a transmission mechanics scanner, a bluetooth OBDII device, and a Smarty S06. I have no issues with any of 4 other devices that have been plugged into the port. Like you, it only happens when the Edge is plugged in to the OBDII port. They then proceeded to only replace 2 of the 5 cables and the EGT. When I brought this to their attention, they hesitated, then said they would replace the cables. Then, they only asked for the unit itself to be sent to them for testing. they acted like I was the first person to report these issues. They never asked about the cables, in fact. They knew they had issues with cables and also issues with EGT sensors. I did some homework before I contacted Edge. My EGT's would read less than the IAT's OH: all my dash gauges drop to zero, a chime would sound, and the gauges would go back to normal. At times everything would read zeros, or I would have the same problem as you. It worked flawlessly for 11 months, then started going haywire. I shelled out a lot of cabbage for the CTS2 with the starter cable, EGT setup, 2 additional sensor cables, and 2 pressure sensors for oil pressure and horn boost. Do a search on here, and you can see for yourself. Its a known issue in our trucks, and other brands even.