actually on the contrary just giving the 180D tells us nothing
we would need the complete model and serial number to determine whats what. Yes the earlier series I, II and III trucks had EV100 systems in them but they were also fitting in a new system at that time during the transition to the Series IV. So if its a Series III it could have either control system in it.
A quick look in the rear would tell you right off if its the GE control or the newer one.
If it is in fact a GE system though the 04 is the start switch low voltage at start up, so like was mentioned , check the accelerator box. The code 06 is the accelerator being pressed without a direction selected.
I myself don't think its the accelerator start switch because your getting the code 06 which is saying the control card is getting a signal to activate the contactors from the accelerator circuit.
You may want to take a close look at the directional switch assy and also check the park brake switch.