DTC 4-7

CELLULAR COMMUNICATION: LEXUS LINK SYSTEM: 4-7: EMERGENCY, VOL+ or VOL- Button has Connection Error

DTC 4-7 - EMERGENCY, VOL+ or VOL- Button has Connection Error

DESCRIPTION

This DTC is output when one of the following occurs: 1) the mayday ECU is malfunctioning; 2) the mayday switch on the map light assembly is malfunctioning; or 3) the wire harness between the mayday ECU and the map light is open.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (MAYDAY ECU - MAP LIGHT (MAYDAY SWITCH))




(a) Disconnect the R23 ECU connector.
(b) Disconnect the X4 map light 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. INSPECT MAP LIGHT ASSEMBLY (MAYDAY SWITCH)




(a) Remove the map light for standard body Removal or long body Removal.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE MAP LIGHT ASSEMBLY (MAYDAY SWITCH) THEN CLEAR HISTORIC DTC
OK -- REPLACE MAYDAY ECU TOGETHER WITH MAYDAY BATTERY AND THEN PERFORM REGISTRATION