2005 equinox with voltage spikes on 02 sensor signal wire and ground wire.

I have a few communication codes but while I was testing the harness side of the o2 sensor, I got voltage spikes over 1.5 and averaging 450mv. The same was on the ground side, I got voltage spikes on the ground side up to 2.5v, koeo. I know the sensor is bad because the heater circuit fault and I had good power and ground. Just wanted to know if the spikes in voltage was normal. It is sensor1 and I had a lean command -21 on the long term.

3.4L engine?

Do you happen to have a capture of the 2.5V spikes on the ground side of the O2? If the engine were running, I wouldn't be surprised. But KOEO is abnormal.

I didn't capture it. I was using my probe 4 and it was capturing min and max voltage. Its hard to find class 2 data splice so I can isolate the modules. My guess is a short to power somewhere.

I don't trust my Power Probe 4 for accurate voltage measurements.

Did you refresh the min-max scales with the tool connected to the circuit to eliminate any readings that may have been recorded while connecting to the circuit?

No I didn't. That's a good point. I will put the scope on it and verify. Thanks for the reply

When I used a multimeter I got the 447 mv this is how it looked on my scope battery negative and 02 signal wire.