Does the ecm use O2 mv for something? If so/not then why does the aldl spit out O2 mv?

 

Yes, it's used in closed loop.
the ecm looks at it only during certain periods. So while to humans that O2 looks to be all over the place the ecm has an agenda as to when to look at it.

It's included so that humans can see it's working somewhat normally.

 

That's what I though, it's for diagnostics. But how does the ecm use mv? It is how the ecm calculates crosscounts? Is that it/all?

 

Ya gotta sit down with some commented code and just read thru it. Several times. The simple explaination is the ecm makes a fueling change, then depending on RPM waits to see a response. The time it waits is in the table area. If it's not within a parameter, for so long then a code 44 or 45 is set.

There's ALOT of stuff going on in this area.

 

Download the ANHT hac and search on "008E". I hope I get this following statement technically correct ...
This address is the RAM address containing the filtered O2 value. It is also the EXACT value that is spit out on the ALDL.
... So, searching the hac for 008E (L008E to be more specific) will yield every place that this value is being used by the code. Note all of the load commands (LDAA, LDAB, and LDX). The mV value located in 008E is being loaded into a section of memory so that the ECM can do work on that value ... analysis ... for a particular purpose. So, YES, it absolutely is being used.

Tim

 

thanks, I'll check that ANHT..