ABS OBD1 code

Probably.
The error icons do disappear randomly, so I have a single ride once in a while without, before they appear again (or reappear mid ride).
Next thing on my to do list, is opening the drum back up, recheck for gunk, and repeat on the other side.
This time around i'll have some ceramic grease to apply on the inside of the drums, as there's nothing there of any kind - bone dry.

Well, I came to realize how much I need a brake shoe replacement in the left side, but other than that, I just got clean brake drums and shoes, and 2 errors I cannot get rid of (error 13 + 14, both rear ABS), after testing abs sensor on the left as well. :)

I've learned one thing, pulling the grounding cable and draining power from the wiring does nothing in regards to resetting the errors, so I may have no bad parts at all, or 2 ABS sensors gone bad after testing.

I asked in local Mazda groups, and one guy mentioned a separate control box for the ABS, that needs resetting by connecting TBS with ground, turning on the ignition, and pressing the brake pedal 10 times in less than 10 seconds, then removing the connecting wire, and ABS errors should be cleared (still waiting on confirmation, as to ignition being on or off, when the connecting wire gets pulled).

I'll let you know if it works out or not.

I achieved partial success. :)

pressing the brake pedal 10 times in less than 10 seconds did the trick in resetting the errors, while TBS and ground was connected - ignition off, pull the wire out from the obd1 port, ignition back on, error free. :)
until I moved at least.
Error 13 came back (rear right), but error 14 (rear left) did not return. :)

i did also notice a big difference in AC when I tested both sides, now that I recall.
I had readings of up to around 0.1 on the left side, when I got it rotating as fast as I could by hand, but was easily achieving 1+ on the right side doing the same.

Do you think a new sensor is going to solve the problem?

I used a full 500 ml can of brake cleaner for the inside of the drums, springs, reluctor wheel and everything in between, on both sides while cleaning - there may be residual brake dust again since I have been driving, but aside from that I would say I was very thorough on that day (even the brake shoes got a bit of sandpaper). :)
adding a before and after photo, of the rear left sensor (the good one).

A sensor doesn't cost a whole lot, thankfully, but before I can replace it and give another update, i'll need to have the remaining piece of the bolt extracted, which keeps the sensor in place on the rear right (it broke, bleh!).

Been a while, honestly forgot about this :-)
i had my local mechanic drill a hole thru the old bolt, so I could get started - I have been problem free since I replaced the sensor, at least in regards to the abs :)
most wiring also seem to resemble the 95-96 Mazda 626's, while basically being '99 protege lx shells, when it comes to the European 98-00 323's.

Yup, once that was replaced, the error disappeared - didn't even have to attempt removing error codes.

Thanks, and you aswell :)