Hello Zhan, the symbol means that you have a travel problem (tire icon), for the error 3012:
1. Disconnect the battery connector and leave the
vehicle for 10 minutes.
2. Disconnect the motor cable from the U, V and W
terminals and measure with the tester between the
motor cable and P terminal and between motor
cable and N terminal. If leaked, remove or repair.
3. Confirm that no foreign matters exist on the P and N
terminals and around the U, V and W terminals.
(Check visually foreign matters on the CPU board.)
4. Confirm that the motor cables are correctly connected
to the U, V and W terminals of motor.
(The cables should be connected to the right and
left terminals without error.)
5. Check the travel (R) controller, travel (L) controller
and cargo handling controller. If abnormal, replace
it. (Replace the CPU board at the same time.)
6. If normal in the above check, replace the travel (R)
controller or travel (L) controller.
regards
marcb