Thanks for your comments.
When i had gone to this truck the engineer had already bypassed the switch with a standard microswitch. I looked like it was simply an on and off position switch.
The strange issue is the truck sometimes works but at slow speed then most of the time it does not work.

This one does not have a zapi or a sauer controller, to be honest i think i have seen something similar to these units on the ac cat counterbalance trucks.

I also think its brake related but cannot proceed any further as i dont have any wiring diagrams/codes etc to help work from.

Thank You for all your comments

my guess is the machine might be in what we call 'limp mode'. This is set when there is a problem with the machine and until the problem is corrected the 'limp mode' will remain. It's like a self protection mode the truck goes into to help cool or keep the operator from driving too fast.

After pondering those brake and foot switch codes i'm thinking there may be an issue with the foot switches under the deadman pedal. Here the mfca built trucks had alot of issues with those switches, mfca came out with updated parts for those switches so now when we run across one giving issues related to the deadman circuit we always replace those switches first. One switch is a brake release switch and the other triggers the controller(s) to turn on.

You might want to check the brake unit and make sure it is releasing, the slow drive might be the brake dragging? Unlikely but it's something to check also. If an electric brake you should clearly hear it pop when it applies and also hear it when it releases.

As for changing the speeds, on certain models the mfca trucks had dash has buttons on it allowing the operator to change operation modes... does this unit have any button indicators? Some models didnt though and the speeds could only be changed using the software program. The one version (first gen AC drive) of that truck with the buttons on the dash had the zapi system in it, the other with the plain display used a sauer danfoss system. I'm thinking the newer models now have a danaher system in it?

Just a few thoughts on this....

Hi mate. Thank you for checking for me.
These units do not have led lights on them. The truck is driving agsin now but stuck in turtle (slow) mode. Would you know how I can get it out of this mode by any chance.

I checked all the code lists for the us mcfa trucks and that code doesn't exist.
Does the controller have a led on it? It might so see if its flashing any codes.

Perhaps someone might have a diffetent AC cat reach with a list of error codes. There is a good chance the codes will be the same as the truck I'm working on.

Thanks in advance