MPC2551 with internal finisher - Jam Code 27

[kannuki2]

Jam Code 27 please help

MPC 2551 with the D429 finisher installed. Machine has been onsite for months. Identical machine in the same office.
When you run a duplexed copy the paper seems to go out to the finisher and throws a jam 27 duplex entrance sensor not actuated. The firmware has been updated and the exit unit replaced. If you remove the finisher the duplex works perfectly.
Not sure what to try next HELP PLEASE

[rsyarcia]

Re: MPC2551 with internal finisher - Jam Code 27

check the connector of the inverter unit and the internal finisher. the inverter unit is not detected properly.

[ccfc87]

Re: MPC2551 with internal finisher - Jam Code 27

What was the outcome of this fault?

I have the same issue. Internal finisher and exit unit are connected properly. I'm going to go back to machine with inverter sensor and refresh the firmware but I'm not convinced this will cure the problem