DTC 4-1

CELLULAR COMMUNICATION: LEXUS LINK SYSTEM: 4-1: Red LED Error

DTC 4-1 - Red LED Error

DESCRIPTION

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






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

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




(a) Disconnect the U46 ECU connector.
(b) Disconnect the W8 map light 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. CHECK OPERATION OF MAYDAY SWITCH ASSEMBLY (RED LED)
(a) Temporarily replace the mayday switch with a new or normally functioning one.
(b) Check that the system operates normally.
OK:
Red LED operates normally.
OK -- END (MAYDAY SWITCH (RED LED) IS FAULTY; CLEAR HISTORIC DTC)
NG -- Continue to next step.

3. CHECK OPERATION OF MAP LIGHT ASSEMBLY
(a) Temporarily replace the map light with a new or normally functioning one.
(b) Check that the system operates normally.
OK:
Red LED operates normally.
NG -- REPLACE MAYDAY ECU TOGETHER WITH MAYDAY BATTERY AND THEN PERFORM REGISTRATION
OK -- END (MAP LIGHT IS FAULTY; CLEAR HISTORIC DTC)