Difference in O2 Sensor Readings

[Hardluck29]

Can someone tell me the most likely thing that is going on with O2 Sensors in this log. I have them disabled and running in SD mode but watching the voltage readings one is definitely doing something different, because its all over the board. I've tried swapping them so I know its not the sensors. I did find a plug wire that was suspect of grounding on the header? Not sure it was causing a problem but could it be? By the way the WB or AFR reading is on the bank 2 side. Hoping someone can tell me. Thanks!

[blindsquirrel]

If the issue did not change banks with moving the sensors, that's a wiring or ECM problem.

[5FDP]

If they both act similar in closed loop then it's fine. Open loop with everything fuel trim related off, they kinda just do whatever sometimes.

[blindsquirrel]

Oh. Well. Whatever is causing your P0641 - 5-Volt Reference 1 Circuit DTC is also taking down a bunch of other sensors and setting other DTCs. You should probably look into that before you waste time on anything else.

[blindsquirrel]

How are you putting it in SD mode? Cause I notice you are logging the MAF channels (don't do that) and at the same time you have a MAP sensor code.

Another tip, don't use the generic SAE channels unless it's a raw voltage signal. Anything that converts a sensor voltage into something else - pressure, volume, position in %, etc. - use the GM-specific version.

[Hardluck29]

It could be a wiring/ecu problem Or an actual problem in the engine which is what I was trying to determine.

[blindsquirrel]

Are the DTCs shown in that logfile real, or have you been unplugging/shorting stuff out with the key on? Clear codes and see which ones come back. The one that is a concern is the P0641 - if that one comes back after clearing, do not waste another minute worrying about anything else until it is fixed.

Where is your tune file?

Are you doing MAF tuning with a wideband in open loop (this is not 'SD')? Or VE tuning with a wideband in open loop(this is 'SD')?I ask because you say 'running in SD mode' but you are still logging MAF stuff, and do not have a P0102 and/or P0103 which usually (not always) show up when the MAF is properly failed, and it's fairly common for new people to confuse 'forcing open loop' with 'running in SD mode', and without your tune file to look at it would take about a hundred questions back and forth to see if you changed the right stuff to put it in SD or if you're just confused about terminology.

Why does speed show 158 MPH all the time? Has somebody done an oopsie and used an auto trans OS with a manual trans?

Using all those (SAE) channels will bite you in the ass eventually, there will be one or more that report values that are not real and you won't know.