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 assembly is malfunctioning; 2) the red LED is malfunctioning; or 3) the wire harness between the mayday ECU assembly and the roof console box assembly (mayday switch assembly) is open or short.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK WIRE HARNESS (ECU - ROOF CONSOLE BOX ASSEMBLY (MAYDAY SWITCH ASSEMBLY))




(a) Disconnect the M16 ECU connector.
(b) Disconnect the O2 roof console box connector.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. REPLACE ROOF CONSOLE BOX ASSEMBLY
(a) Temporarily replace the roof console box assembly Removal with a new or normally functioning one.
(b) Check that the system operates normally.
OK:
Red LED operates normally.
NOTE:
If replacement of the ECU is necessary, replace the mayday battery (backup battery) together with the ECU. After the replacement, register the ECU Programming and Relearning.

NG -- REPLACE MAYDAY ECU ASSEMBLY
OK -- END