Error Code Occurs During ECU Upgrade (5021-10-7005)

Symptom:  Error code [5021-10-7005] occurs during an ECU upgrade.

Cause:  A CAN BUS fault occurs in response to the ECU upgrade communication open command.

Solution: 

1. Check whether any aftermarket equipment is installed in the vehicle.
2. Verify that the diagnostic tool is properly connected and that the sensor output from the target control unit is displayed normally.
3. If the connection and sensor output are normal, retry the ECU upgrade.