RomRaider

I've been doing P0420 and P0430 fixes by replacing the 00 A0 00 A0 with 00 00 00 00 for years with no issues and I noticed another person's file with P0420/P0430 fix is also all 00 00 00 00.

What does the A0 mean and what does 20 mean? What would 20 do differently to 00 which also seems to fix these codes?

Thanks in advance!

I'm not sure what you're referring to exactly. The way A33B handles it is setting the table values to 1. Are you referring to making changes to the physical code rather than to the table value? All you really need to do is adjust the table value. It's the mTCNGM table in the A2L. (Not defined in my public repo)

Changing these values are a means of changing the behavior when the DTC is triggered. This keeps the emissions code active, but prevents the CEL from illuminating. 00 00 will also work to accomplish this but also toggles another bit, I'm not 100% certain of each bits function.

I've since learned how to disable certain DTCs entirely. (for off-road / dedicated race purposes of course!)