DTC B1556: Extension Module Malfunction 2 [09/2020 - ]: Procedure

1. Clear the DTCs.

   Body Electrical > Navigation System > Clear DTCs 

2. Recheck for DTCs and check that no DTCs are output.

   Body Electrical > Navigation System > Trouble Codes 

   OK

   No DTCs are output.

   Result

   Proceed to
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2020 - 11/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [11/2021 - 09/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [09/2022 - ] 

Result: 

NG 

REPLACE NAVIGATION ECU. Refer to  REMOVAL [09/2020 - ]