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clinebarger · 10-19-2015, 06:47 PM

What year 5.3L? .450 MV is "Threshold" Voltage, Thats what will read all the time if there is a open circuit in the Ground or Signal circuits, Both O2's having this issue would lead me to a Ground issue, A lot of the early LS engines have a Case Ground for the O2's, Later ones use the Low Reference bus it the PCM.

10-19-2015, 06:47 PM	#2
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: No 02 activity What year 5.3L? .450 MV is "Threshold" Voltage, Thats what will read all the time if there is a open circuit in the Ground or Signal circuits, Both O2's having this issue would lead me to a Ground issue, A lot of the early LS engines have a Case Ground for the O2's, Later ones use the Low Reference bus it the PCM.