Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM000001EFZ004X
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: CELLULAR COMMUNICATION: LEXUS LINK SYSTEM: 4-1; Red LED Error; 2007 MY LX470 [08/2006 -        ]

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 map light plate assembly (mayday switch assembly) is open or short.

DTC No.

DTC Detection Condition

Trouble Area

4 - 1

Communication or communication line is abnormal between mayday ECU and map light plate (mayday switch)
  • Mayday ECU assembly
  • Map light plate assembly
  • Mayday switch assembly
  • Wire harness

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK WIRE HARNESS (ECU - MAP LIGHT PLATE ASSEMBLY (MAYDAY SWITCH ASSEMBLY))

(a) Disconnect the M15 ECU connector.

(b) Disconnect the O4 map light plate connector.

(c) Measure the resistance of the wire harness side connectors.

Standard resistance:

Tester Connection

Specified Condition

M15-4 (IND1) - O4-4 (IND1)

Below 1 Ω

M15-4 (IND1) or O4-4 (IND1) - Body ground

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS AND CONNECTOR THEN CLEAR HISTORIC DTC

OK

2.

CHECK OPERATION OF MAYDAY SWITCH ASSEMBLY (RED LED)

(a) Temporarily replace the mayday switch assembly with a new or normally functioning one.

(b) Check that the system operates normally.

OK:

Red LED operates normally.

OK

END (MAYDAY SWITCH ASSEMBLY (RED LED) IS FAULTY; CLEAR HISTORIC DTC)

NG

3.

CHECK OPERATION OF MAP LIGHT PLATE ASSEMBLY

(a) Temporarily replace the map light plate assembly with a new or normally functioning one.

(b) Check that the system operates normally.

OK:

Red LED operates normally.

NG

REPLACE MAYDAY ECU ASSEMBLY TOGETHER WITH MAYDAY BATTERY AND THEN PERFORM REGISTRATION

OK

END (MAP LIGHT PLATE ASSEMBLY IS FAULTY; CLEAR HISTORIC DTC)