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 telephone ECU assembly does not recognize the mayday battery (backup battery), this DTC is stored.
HINT:
This DTC is only a historic DTC.





WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (TELEPHONE ECU ASSEMBLY - MAYDAY BATTERY)





(a) Disconnect the P3 ECU connector.
(b) Disconnect the P4 battery connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR THEN CLEAR HISTORIC DTC
OK -- Continue to next step.
2. REPLACE MAYDAY BATTERY (BACKUP BATTERY)
(a) Replace the mayday battery Removal.
(b) Perform registration Programming and Relearning.
(c) Check for DTC again Reading and Clearing Diagnostic Trouble Codes.
OK:
No DTCs output.
NG -- REPLACE TELEPHONE ECU ASSEMBLY THEN PERFORM REGISTRATION
OK -- END (MAYDAY BATTERY IS FAULTY; CLEAR HISTORIC DTC)