GM O2 Sensor Meter Testing on Two Different Grounds

GM MAP Sensor Meter Testing

GM O2 Sensor Testing with a Meter

Testing AC Voltage On a Battery Charger

GM O2 Sensor on Chassis Ground

GM O2 Sensor on Signal Ground...Test the O2 sensor the proper way on the signal ground NOT chassis ground.

Parasitic Draw Battery Drain Check With Snap On Zeus labscope and Fluke I30s amp clamp

An EXAMPLE of a Big Voltage Drop on the ground side of an engine. We hope this explains what happens on many vehicle when there is a voltage drop.