Aem uego reading different then aem tuner program

SO I'm trying to figure out why my aem uego wideband gauge is showing completely different then what the lap top is seeing. I have the red wire of the wide band going to a switched 12v from the ecu, black going to the chassis with the paint grinded off, and the white wire going to o2 #1. According to the aem uego instructions, with the sensor disconnected from the gauge you should get a v reading of 2.35 and a reading of 14.8. The lap top is showing me 2.42 v and a reading of 14.8 which matches the gauge. Once I plug the sensor back in it gives me a reading of 3.7v and afr 17.8, which also matches the gauge. But once I start the car the gauge will show 12.8 while the laptop shows 14.3. This is at idle, operating temp. Any suggestions? I'm thinking The gauge is what is reading incorrectly and not the ecu as my target afr's are being hit (according to the lap top)

This is a relatively common issue with analogue voltage input wideband controllers and is usually caused by a ground offset. Normally it's advisable to connect the ground or zero volt wire from the wideband controller to a sensor ground wire on the ECU to minimise the potential for these offsets. I'd suggest trying this as your first step.

I believe there are only 2 sensor grounds on the aem 6100, is there a chance of causing any ecu damage by having to many grounds hooked up to the ecu?

It's common that an ECU will only have perhaps 2-3 sensor grounds. These are different from the power grounds and are there to ensure the delicate sensors have a dedicated and accurate ground reference. You can share these grounds among all your sensors. As a matter of good house keeping I try and distribute the sensor grounds as evenly as I can among the different sensor ground pins at the ECU header.

Even with the sensor ground perfect, you may still find that some minor scaling of the calibration will be required. I've used a number of Innovate widebands and the factory calibration always needs a small amount of adjustment so that I end up with the same reading on the laptop and the gauge.

Thanks Andre! After grounding to the sensor ground I still noticed the gauge and ecu were still not accurate. Wound up adjusting the o2 cal and everything is golden now!

Glad you got it sorted. This is why I much prefer CAN-based wideband controllers, as the integrity of the data being transferred is guaranteed. I've wasted many hours attempting to get wideband calibrations to match and it's very frustrating.