Nissans with this system are know to pop Transistor when a load is on them that is not normal, like pushing pallets of beer across the warehouse. I have replaced so many panels and transistors its crazy!

If you are drawing massive amperage through the system with maybe a bad battery, or even a bad Motor, The field windings of the motor or the armature, commutator all of these are potential issues. 012 being PS pump motor code first are the brushes welded to the commutator?

You have a massive draw or short in the system the power cables running through the frame and under the battery I would check first.

Diagnostic mode: Hold 1 & 4 turn key on, push 3
To run self diagnostic
Hold 1 & 4 turn key on, Put in Forward, and push 1

Programming: Use on board system with dash display
Hold 1 & 3 and turn key on
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Also don't forget the normally closed side of the Directional Contactors, the 1A , and flyback contactor.

One other thing is the main speed board in the back that covers the contactors, if that touches one of the contactor bars because someone pushed on the back door or whatever it will blow the board and the transistors immediately.