Canon CLC 1120 error message

[gerwhoa]

Hi, Our cust is getting an E020 0181 error during initialization. I have replaced the environment pcb and sensor because the test for those parts was way off, per the repair manual specs. No fix. I have the repair manual, and have much experience on laser printers, but I have zero experience on this copier. This is a good customer & I am trying to help them out.

[SCREWTAPE]

The black ATR toner sensor is probably dirty with yellow stray toner.
This might be occuring because of your yellow developer is weak.