hi Donald,
Note: try and make sure the battery cells are filled to the correct level and is charged up fairly well, if not then charge it before you start. This goes for any electric truck you need to troubleshoot so you can get accurate voltages when testing with a multimeter.

First off, i'm very limited on my raymond info but if the trucks between the ET-B and ET-F hold true to their operating systems this code 45 has to do with the PC Contactor not closing when commanded. And if it is pulling in and dropping out on startup it may indicate other problems such as the steering circuit.

The only suggestion it gives on this code 45 is to run test O01 to test the contactor, and then run test I14 to check the FU1 fuse if they do close on the O01 test.
This is testing for a signal through the deadman switch circuit to the PC Contactor.
Now after looking deeper into this FU1 has to do with the steering circuit. FU1 is a 150amp fuse located on the fuse panel. (there should be 2 other fuses besides this one, FU2 and FU3, they are large buss fuses so do not confuse this with the small glass fuses).
Question: does the pc contactor pull in and drop right back out real quick? (also check the contactor and make sure the tips are not stuck together).
This would explain why it would be coding out during startup. It may have a steering motor circuit problem, possibly an open fuse.

There is also a note to check the contactor tips for being burned, suggests measuring battery specific gravity and cell voltage. Adjust battery cutout if it is too low.
FYI: to run these tests you need access to the maintenance menu's in the control system, this requires a passcode, raymond tech's were trained to change that from the factory codes of RAY1 and RAY2 to a special code they regularly change from month to month. If this is the case with your unit and you do not know the passcode then you cannot run the tests and will have to do this the old fashioned way using a meter and proving out the components and wiring.
I hope this isn't too confusing and helps you somewhat.
If none of this matches up with the configuration on the truck then i'll have to dig some more and see if i can find more accurate info for you.