Master cylinder code - bleed system ?

[palsmith]

Following up on ABS module thread from yesterday. So I used my scanner and read codes. It showed a master cylinder low/ pressure sensor. Sure enough it was low - I guess I had ran low on fluid when bleeding brakes and hadn’t noticed. Feel pretty dumb as I have bled brakes on this car a couple dozen times.

I filled to normal level but code won’t clear. Should I bleed master cylinder and then system?

 

[palsmith]

As a follow up, the car seems fine but even with the stock ABS (not Boss race) module, I have all kinds of codes. I've reset and keep getting a C1A99 brake pressure sensor code?

 

[TMSBOSS]

Some folks have had good luck with bleeding brakes, taking the car out and activating the ABS, gravel road should be safest. Then bleed again. Air in the ABS should clear. .