DTC B278D: ID Code Box Judgment Circuit [11/2021 - ]: Procedure

1. Turn the ignition switch to ON.
2. Using the GTS, perform the clear DTCs of [Keyless Access with Push Button Start(Collation)].
3. Turn the ignition switch to OFF → ON.
4. Read the DTC of [Keyless Access with Push Button Start(Collation)] using the GTS.

   Is DTC B278D displayed? (Current code)

   Result	Proceed to
   Yes	A
   No (Even if DTC is displayed, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.) HINT:  In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.	B

Result: 

B 

END 

1. Even if DTC is displayed, the circuit has returned to a normal condition at this time.
2. Reproduce the failure, and then perform the diagnosis again.

   HINT: 

   In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.

Result: 

A 

See step  2

1. Turn the ignition switch to OFF.
2. Disconnect the smart key ECU assembly connector.
3. Measure the resistance between smart key ECU assembly connector and chassis ground.

   Connector & terminal

   F8-18 (IDW) - Chassis ground

   Is the resistance less than 1 Ω?

   Result	Proceed to
   Yes (Replace the smart key ECU assembly.)	A
   No (Repair or replace the open circuit of harness.)	B

Result: 

A 

REPLACE SMART KEY ECU ASSEMBLY. Refer to  REMOVAL [11/2021 - ] 

Result: 

B 

REPAIR OR REPLACE THE OPEN CIRCUIT OF HARNESS