04 Dodge Ram 1500 5.7 02 P0038

The pcm is throwing a code for the heater circuit high downstream bank 1. I checked the signal return on the bank 2 downstream and their was a few squarewaves at ken on engine off and then constant squarewaves as soon as i started the engine. the side that the code was for had a sqarewave that was dropping out at key on engine off and nothing at key on engine on. this is a power side switched pwm circuit. Ive attached a picture of the squarewave dropping to zero. this is my first scope and im sort of confused. to me it seems like the key on engine off pattern is a test that is failing and the the the dropping out causing it is either a short to ground on the wire or a bad pcm shorting the circuit? Am i right at all? the 02 has been replaced

I just looked at mitchell diagram and it looks like the pwm lines are on only on bank 2 o2 sensors... ck. it out, it maybe a misprint. & don't know why Dodge would do this. But if its legit it may explain why your getting drop out from bad heater or circuit wiring, good luck!

check the wires, they tend to rub through near the front drive shaft. an intermittent short can cause what you're seeing on the scope.