[Error Code] L4-31

[fanasa]

I have a problem with a MX4501. It has a L4-3 code. The PCU PWB and the fans have been replaced. Code is still there.
All connections are good.
Has anyone seen this where the above haven't fixed it?
Please let me know

[OMD-227]

L4-31 is an exit fan trouble code.

Are these the fans you mentioned were replaced?

Run the fan test in sim 6 to see if they are rotating. You can also feel air exiting the vents on the upper right side cover. This fan has also had a new part number (NFANP0077FCZ1, was FCZZ). If the fans are both rotating, then one of them has no return signal. Check the cabling to the delivery unit & harness pins/plug on the PCU board.
You can also take the whole delivery unit out, and run the fan sim test while holding the delivery unit in your hand. This is a much easier way to see if a fan is either not working, or rotating too slowly.

Has this machine recently had a new main drive unit? If the machine was manufactured before January 2008, you need to cut the small loop on the harness going to the PCU board (CN9 from memory). The new main drive units have a different harness due to the extra colling fan for the black toner in machine made after January 2008. The code L4-31 will come up if that small grey wire loop on the PCU board plug is not cut/sealed off.

They are the olny causes for that code. Unless one of the other fans are pulling the 5v line down, I'm thinking you have a faulty fan/signal line or a bent pin somewhere.

[fanasa]

Thanks so much for your quick response. we will give this a try.

[S Hartleben]

Thank you

I used this information and it worked..