DTC C1789: Vehicle Identification Malfunction [08/2019 - ]: Procedure

1. Perform registration.

   Refer to REGISTRATION [08/2015 - ]

   Result

   Result
   NEXT

Result: 

NEXT 

See step  2

1. Clear the DTC.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

2. Check if DTC C1789 is output.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

   OK

   DTC C1789 is not output.

   Result

   Result
   OK
   NG

Result: 

OK 

END 

Result: 

NG 

See step  3

1. Check that the part number of the installed ECM is correct.

   Refer to REMOVAL [08/2015 - ]

   NOTE:

   When removing the ECM to check the part number, or when replacing the ECM, be sure to follow the appropriate procedures and precautions.

   OK

   ECM with correct part number is installed.

   Result

   Result
   OK
   NG

Result: 

NG 

REPLACE ECM. Refer to  REMOVAL [08/2015 - ] 

Result: 

OK 

See step  4

1. Clear the DTC.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

   Result

   Result
   NEXT

Result: 

NEXT 

See step  5

1. Check if DTC C1789 is output.

   Refer to DTC CHECK / CLEAR [08/2019 - ]

   OK

   DTC C1789 is not output.

   HINT: 

   If no parts are replaced and DTC C1789 is output, there may be an internal malfunction in the suspension control ECU. In this case, replace the suspension control ECU.

   Result

   Result
   OK
   NG

Result: 

OK 

USE SIMULATION METHOD TO CHECK. Refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2019 - 08/2020]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2020 - 08/2021]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2021 - 08/2022]  , or refer to  HOW TO PROCEED WITH TROUBLESHOOTING [08/2022 - ] 

Result: 

NG 

REPLACE SUSPENSION CONTROL ECU. Refer to  REMOVAL [08/2015 - ]