I had the same error on both machines "CK L COIN DETCTR".
I decided to take one out and clean it and the coin hopper. I really did not know what to do. I just knew neither changer worked. I also dumped the coins out of the coin dispenser assembly. I concentrated on the coin leds and censor.
It seems to work but I will have to check tomorrow. Also, I love the Rowe instructions it seems to always boil down to replace the CCC.