Oh welcome to the joys of owning a Pole Position. I know Ian does do some repairs on them if he's not too busy. Is the board getting the proper voltage? I'd definitely start there.
I'm not sure where your abilities like, but there is a table on page 25 of the PDF that might be helpful:
http://www.arcade-museum.com/manuals-videogames/P/polepos.pdfCheck the ram at 8F, 8H, and 4F (per the table) on the video PCB for your error codes. It may be one or none of those... Perhaps some of the smarter folks will chime in!