3rd gen ECU AFR read out

Specifically talking AFR. Is this commanded read out or actual from the O2 sensors?

 

Not sure what you’re asking exactly. Are you asking if the voltage from O2 sensor is read directly vs it being interpreted by ECU and “sent” on the canbus upon request?

 

To clarify, is the AFR an actual read out or is the ECU reading another element besides exhaust gases and calculating what the AFR should be? Just trying to understand how the ECU is arriving at the number shown. I know after market set ups measure pre cat exhaust via a sensor (that would be an example of actual reading)

 

Depending on the PID you've selected, it could be the actual AFR measured by the factory wideband sensors pre-cat or the target AFR commanded by the ECU.

If it oscillates a bit at idle/cruise, it'll be one of the actual observed AFRs at that bank measured by one of the factory widebands. If it's a stable/fixed value, it'll likely be the target AFR set by the ECU for the particular conditions/load/RPM present.