Disclaimer: this is jeffs80s wife. I diagnosed and wrenched on my first car today taking it from not driving to driving (feeling accomplished) and I am trying to figure out the rest so my husband can get a break with this stuff for once so please bear with me. I'm sure I sound like I have no idea what I'm talking about. Thank you.

Hi my 2000 Volvo s80 broke down and read codes 1633 and p0304 (engine coil #4 misfire) I replaced the coil and it runs again but code 1633 persists.
symptoms:
intermittently says brake failure stop
abs / brake / slipping traction control lights come on intermittently (no cruise control)
engine light (code 1633)

from what I have searched that means ABS module but what does that mean? Does it need to be replaced? (I hear finding a used one to marry and work is difficult and new is 600+ and will it really fix my problem or could it be ecm or cem instead and a wasted 600?)
Is this going to end me up on the side on the road broken down again if not taken care of?


My husband and I currently have 2 Volvos the other is a 2001 s80 t6 also having abs module and/or possible CEM issues.

 

Did you repalce the ABS module? If not pull your old mod out ( very simple and send it here https://midwest-abs.com/ .......On his website it has a video on how to remove. He guarantees them for life. I sent him mine and hetested it...sent it back and said there is no problem.
I am having the same problem and get the code P1633 as well. I have not figured mine out as of yet. If you have resolved your issue, could you let me know what you did?