DTC C1789: Vehicle Identification Malfunction [08/2015 - 08/2018]: Procedure

1. Perform registration (Refer to REGISTRATION [08/2015 - 08/2019] ).

Result: 

NEXT 

See step  2

1. Clear DTC (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).
2. Check if DTC C1789 is output (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

   OK

   DTC C1789 is not output.

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 - ] for 3UR-FE, Refer to REMOVAL [08/2015 - 08/2018] for 3UR-FBE).
   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		Proceed to
   OK		A
   NG	for 3UR-FE	B
   	for 3UR-FBE	C

Result: 

B 

REPLACE ECM 

(Refer to REMOVAL [08/2015 - ] )

Result: 

C 

REPLACE ECM 

(Refer to REMOVAL [08/2015 - 08/2018] )

Result: 

A 

See step  4

1. Clear the DTC (Refer to DTC CHECK / CLEAR [08/2015 - 08/2019] ).

Result: 

NEXT 

See step  5

1. Check if DTC C1789 is output (Refer to DTC CHECK / CLEAR [08/2015 - 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: 

OK 

USE SIMULATION METHOD TO CHECK 

(Refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2015 - 08/2017] , or refer to HOW TO PROCEED WITH TROUBLESHOOTING [08/2017 - 08/2018] )

Result: 

NG 

REPLACE SUSPENSION CONTROL ECU 

(Refer to REMOVAL [08/2015 - ] )