Lexmark cx417de ADF detection issue

Greetings. My printer has just stopped taking source material from the ADF feeder, copies or scanning. I've updated the firmware, performed a factory default, cleanerd the rollers and the ADF in genral. The green light comes on with I put a sheet in the ADF, but paper is just not picked up, printer scans from glass every time. Considering the ADF duplex assembly is close to 1k, I'd like to do everything I can before changing it.

Any help is greatly appreciated!

Thanks.