Pre-Crash Safety. Dtc B2075 Passenger Side Seat Belt Buckle Switch Circuit Malfunction

CHECK HARNESS AND CONNECTOR (SEAT BELT CONTROL ECU - FRONT SEAT INNER BELT ASSEMBLY)

DTC B2075 Passenger Side Seat Belt Buckle Switch Circuit Malfunction

DESCRIPTION

This DTC is stored when there is a malfunction in the front seat inner belt buckle switch circuit for the passenger side. The seat belt control ECU receives buckle switch condition information from the front seat inner belt and controls the pre-crash safety system.

DTC Code	DTC Detection Condition	Trouble Area
B2075	A malfunction in the front seat inner belt (buckle switch) circuit.	Front seat inner belt assembly (for passenger side) Harness or connector Seat belt control ECU

WIRING DIAGRAM

Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Pre-Crash Safety.Pre-Crash Safety System.
Dtc
B2075 Passenger Side Seat Belt Buckle Switch Circuit Malfunction

INSPECTION PROCEDURE

1.CHECK FOR DTC

Clear the DTCs (LandCruiser RM0000043K500GX.html).

Check for DTCs (LandCruiser RM0000043K500GX.html).

OK:: DTC B2075 is not output.

Go to step 2

USE SIMULATION METHOD TO CHECK (LandCruiser RM000003YMJ00XX.html)

2.CHECK SEAT BELT CONTROL ECU

Remove the seat belt control ECU, but do not disconnect the connector (LandCruiser RM000003UX700KX.html).

Using an oscilloscope, check the waveform.
Measurement Condition
Item
Content
Tester Connection
G118-5 (PBK+) - G118-6 (PBK-)
Tool Setting
2 V/DIV., 20 ms/DIV.
Condition
Ignition switch ON, front seat belt (for passenger side) fastened → unfastened
OK:
Waveform is as shown in illustration.

Measurement Condition
Item	Content
Tester Connection	G118-5 (PBK+) - G118-6 (PBK-)
Tool Setting	2 V/DIV., 20 ms/DIV.
Condition	Ignition switch ON, front seat belt (for passenger side) fastened → unfastened

Go to step 3

REPLACE SEAT BELT CONTROL ECU (LandCruiser RM000003UX700KX.html)

3.CHECK HARNESS AND CONNECTOR (SEAT BELT CONTROL ECU - FRONT SEAT INNER BELT ASSEMBLY)

Disconnect the G118 ECU connector.

Disconnect the Q21*1 or R34*2 belt connector.
1. *1: for LHD
2. *2: for RHD

Measure the resistance according to the value(s) in the table below.

Standard Resistance:
for LHD
Tester Connection
Condition
Specified Condition
G118-5 (PBK+) - Q21-5 (RBE+)
Always
Below 1 Ω
G118-6 (PBK-) - Q21-4 (RBE-)
G118-5 (PBK+) - Body ground
Always
10 kΩ or higher
G118-6 (PBK-) - Body ground
for RHD
Tester Connection
Condition
Specified Condition
G118-5 (PBK+) - R34-5 (LBE+)
Always
Below 1 Ω
G118-6 (PBK-) - R34-4 (LBE-)
G118-5 (PBK+) - Body ground
Always
10 kΩ or higher
G118-6 (PBK-) - Body ground

for LHD
Tester Connection	Condition	Specified Condition
G118-5 (PBK+) - Q21-5 (RBE+)	Always	Below 1 Ω
G118-6 (PBK-) - Q21-4 (RBE-)
G118-5 (PBK+) - Body ground	Always	10 kΩ or higher
G118-6 (PBK-) - Body ground

for RHD
Tester Connection	Condition	Specified Condition
G118-5 (PBK+) - R34-5 (LBE+)	Always	Below 1 Ω
G118-6 (PBK-) - R34-4 (LBE-)
G118-5 (PBK+) - Body ground	Always	10 kΩ or higher
G118-6 (PBK-) - Body ground

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE FRONT SEAT INNER BELT ASSEMBLY (for Passenger Side) (LandCruiser RM000003RQO025X.html)