Hi
Mod 5 is the AC2 pump controller
VMH high(48V) possible causes

A, there is a problem in the motor cables or the motor power curciuts check the 3 phases are correctly connected also check for earth faults
B, faulty invertor

to check the invertor the pump and drive invertors are exactly the same the only difference is one of them has a link cable on one of the plugs they only take about 20mins to swap around aslo check the wiring to the multipin plug on the invertor i have had quite a few problems with broken wires where they go into the pins

another thing to check that might sound daft but on all the hyster matrix range it is critical that the beacon is ok a faulty or incorrect beacon will throw up all sorts of errors on these trucks i always disconnect it first and a lot of times the error disapears