I have a MXM7570 that keeps throwing a L4-43 code every day or two. First I replaced paper exit cooling fans 5 and 6, no change. Then I replace the whole paper exit unit. It came back in 2 days. I called Sharp and started a ticket but they were of little help and didn't acknowledge any of the items I did before calling them. I then replaced the PCU board and it went about a week and a half but now I am back today. My question for Sharp and reason for calling was that on the old MX-3500 series we would get a paper exit cooling fan error code but the failure was the toner cooling fans and it seemed logical that perhaps there was another fan as the culprit. Has anyone had this failure that can shed some light on a possible cause. All the fans work when I test them in SIM 6. Power is clean with filter attached. The unit has about 1.6M on it.