DRV8873HEVM: Fault pulled low

Hi team,

Here's an issue from the customer may need your help:

The DRV8873HPWPR is driving a push-bar (brushed DC) using PH/EN mode to signal EN.

Without the motor, the motor is enabled, commutated, and the voltage across OUT1 OUT2 is the same as the truth table. When the motor is connected, Sometimes the motor works properly (during normal operation, the current starts at about 3.5A and runs at 2A), and sometimes nfault pulls down directly and does not work properly. When enabled, the chip immediately enters protection when the motor is commutating during operation. 

1) What could be the possible cause of the above issue?

2) How to set the ITRIP hardware version (non-SPI version)? 

3) Is it related to open load detection? How does this feature turn off? 

Thanks.

Best Regards,

Cherry