Any way to prevent power state change from ON to OFF automatically when sitting in KOEO?

Currently verifying an on-board charger repair (replacement). Previously charger set a P0D67-844 when duty-cycle shifted from 50% to 77%. Verified duty-cycle at CHST matched live data with an oscilloscope, so I ordered and installed an on-board charger. I try to be thorough, so I wanted to record the duty cycle PID and verify the issue is resolved. Which brings me to my question…

In order to view live data while charging, the power mode must be ON. Every two or three minutes, the car turns itself off and the scanner stops recording. Is there any way to force the car to stay on? I supposed I could just let the battery fully charge and view its success as proof of repair, but I'd rather actually see the duty cycle shift in data. 

Edit: no solution yet, but I did realize that I had my cause/effect relationship wrong with the original diagnosis after looking at the data with the good charger and reviewing the data from the old charger. The shift from 50% to 77% duty is a response to a decreasing output voltage. After zooming in to the output voltage and duty cycle in the data from the bad charger, I can see that the charging voltage started to decrease a fraction of a second before the duty cycle started to increase. I was thinking that the charger was crapping out when higher output was demanded, but it was the other way around; the charger was trying to increase output it saw a drop in output. I'll just leave this here for posterity.