AC DRIVE CONTROLLER ERROR CODE 73 OR/AND 36

Error code 73 and 36 are similar and result in the same issue. The drive systems will be very slow motor/drive movement. Almost 1 MPH. It will move for about 10 feet and stop trying. Motor will make a weird noise. Also, motor does develop heat rapidly. 

This issue is due to the speed controller not getting the correct signal from the encoder/speed sensor mounted at the rear of the drive motor. The speed controller and the encoder are a closed loop system. Without the correct signal the drive system will not operate correctly. This can be cause by:

1. Most common is a faulty encoder. These are very high pulse rate units. 64 pulses per motor/ revolution. Without correct equipment or the speed controller diagnostic tool you will not be able to test the encoder and just replacement is your best option. 
2. Faulty wiring from the speed controller to the encoder. Visually inspect wiring for signs of loose connection of corrosion. If any found either repair or replace wiring. Power can be checked to the encoder to make sure it's got its 5VDC supply. See vehicle wiring diagrams.   
3. Extremely rare but an issue with the speed controller itself.