DTC 6-4

CELLULAR COMMUNICATION: LEXUS LINK SYSTEM: 6-4: Backup Battery Connection Error

DTC 6-4 - Backup Battery Connection Error

DESCRIPTION

After the engine switch is turned on (IG) and 10 seconds or more have passed, if the mayday ECU does not recognize the mayday battery (backup battery), this DTC is output.
HINT: This DTC is only a historic DTC.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK WIRE HARNESS (MAYDAY ECU - MAYDAY BATTERY)




(a) Disconnect the U46 ECU connector.
(b) Disconnect the U47 battery connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR THEN CLEAR HISTORIC DTC
OK -- Continue to next step.

2. REPLACE MAYDAY BATTERY (BACKUP BATTERY)
(a) Perform registration Programming and Relearning.
(b) Check for DTC again.
OK:
No DTCs output.
NG -- REPLACE MAYDAY ECU THEN PERFORM REGISTRATION
OK -- END (MAYDAY BATTERY IS FAULTY; CLEAR HISTORIC DTC)