2015 Chevrolet Silverado 1500 High Country 6.2L (J L86) 8-spd (8L90)
This is a known good initial key on cycle signal circuit self test from the SDM for the drivers door impact sensor. This was tested at the sensor with the sensor disconnected. This self test waveform is similar to many late model General Motors impact sensor signal circuits that I have tested . Roughly 7 volt feed pulsed to ground a couple times to verify circuit integrity and and trying to communicate with the sensor.