GEM 2003 - -90 Code? Help

We recently bought a used 2003 GEM. The seller had allowed batteries to dry and we only were able to drive a short test drive. We knew it needed batteries. We drove it a few blocks and began seeing -90 code (all power gone). This happened several times. Once we replaced batteries, we hoped this would be solved. It did not. We continue to drive several miles. Battery level will be 95% and with no warning, the power is gone and -90 code flashes. GEM repair guy has no idea and has never heard of -90? Book does not show this code? Has anyone seen this or have any ideas? Thanks,


90 terminal one is shorted to ground, input sensor error inspect motor controller

We had the motor re built/ The man said the coil was bad and it was in fact overheating. We thought we had problem solved until we all 4 went for a right up hill few blocks and -90 code appeared again. Does this mean the controller is bad as well?