I have a question. I was reading in a service book that when the ECM is put into diagnostic mode with the 10K resistor the ECM uses a different set of calibration tables.

there was also a warning not to drive while in this mode.


so how can using a scan tool like craigs work when the data it is reading isnt the same as when there is no scan tool hooked up?

maybe I am missing some thing but I definently notice a difference in how my car runs when I am scanning it



my 2 cents

 

On SD there is a specific "Normal Mode' of operation to ensure the ECM does not "override" certain parameters as it might in ALDL Mode. This is one of my reasons for preferring SD.

I have noticed on the MAF cars I have played with that I did have to run in ALDL Mode with my Diacom+. I would say the effects of "overriding" on the 165 MAF (with ARAP BIN derivative) did not seem as pronounce as it was on a some other ECMs (e.g. 7747) that I've played with.

I haven't studied the" MAF hac" enough to see what exactly is "overridden" by the MAF ECM. That is something you MAF guys might want to undertake and possibly change.