DTC B1206 P/W Master Switch Communication Stop

DESCRIPTION

This DTC is detected when communication between the multiplex network master switch (power window master switch) and gateway ECU stops for more than 10 seconds.

DTC No.	DTC Detection Condition	Trouble Area
B1206	Multiplex network master switch communication stops	Multiplex network master switch assembly (power window master switch) Wire harness

WIRING DIAGRAM

Dtc B1206 P/W Master Switch Communication Stop. MULTIPLEX COMMUNICATION. Lexus IS250 IS220d GSE20 ALE20

INSPECTION PROCEDURE

HINT:

When "+B of GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1206, repair the "+B or GND short malfunction of communication bus" DTCs first.

1.INSPECT FUSE (FR DOOR LH)

Remove the FR DOOR LH fuse from the main body ECU LH (cowl side J/B LH).

Measure the resistance of the fuse.

Standard resistance:
Below 1 Ω

REPLACE FUSE

OK

2.CHECK WIRE HARNESS (POWER WINDOW MASTER SWITCH - BATTERY AND BODY GROUND)

Dtc B1206 P/W Master Switch Communication Stop. MULTIPLEX COMMUNICATION. Lexus IS250 IS220d GSE20 ALE20

Disconnect the M7 switch connector (for LHD).

Disconnect the L17 switch connector (for RHD).

Turn the engine switch on (IG).

Measure the voltage and resistance of the wire harness side connector.

Standard voltage:
Tester Connection Condition Specified Condition
^*1BDR (M7-10) - Body ground
^*2BDR (L17-10) - Body ground Always 10 to 14 V

HINT:

*1: LHD

*2: RHD

Standard resistance:
Tester Connection Specified Connection
^*1GND (M7-2) - Body ground
^*2GND (L17-2) - Body ground Below 1 Ω

HINT:

*1: LHD

*2: RHD

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.CHECK RESISTANCE OF COMMUNICATION LINE

Disconnect the M7, Q3 and P33 ECU connectors (for LHD).

Disconnect the L17, RJ and P33 ECU connector (for RHD).

Dtc B1206 P/W Master Switch Communication Stop. MULTIPLEX COMMUNICATION. Lexus IS250 IS220d GSE20 ALE20

Measure the resistance between the specified terminals on the wire harness side connectors.

Standard resistance:
Tester Connection Specified Condition
^*1MPX1 (M7-7) - MPX1 (Q3-15)
^*2MPX1 (L17-7) - MPX1 (P33-27) Below 1 Ω
^*1MPX2 (M7-8) - MPX2 (P33-28)
^*2MPX2 (L17-8) - MPX1 (RJ-21) Below 1 Ω

HINT:

*1: LHD

*2: RHD

Result:
Result Proceed to
Both are OK A
One is OK B
Both are NG C

REPAIR OR REPLACE HARNESS OR CONNECTOR AND REPLACE POWER WINDOW MASTER SWITCH

REPAIR OR REPLACE HARNESS OR CONNECTOR

REPLACE POWER WINDOW MASTER SWITCH

Tester Connection	Condition	Specified Condition
^1BDR (M7-10) - Body ground ^2BDR (L17-10) - Body ground	Always	10 to 14 V

Tester Connection	Specified Connection
^1GND (M7-2) - Body ground ^2GND (L17-2) - Body ground	Below 1 Ω

Tester Connection	Specified Condition
^1MPX1 (M7-7) - MPX1 (Q3-15) ^2MPX1 (L17-7) - MPX1 (P33-27)	Below 1 Ω
^1MPX2 (M7-8) - MPX2 (P33-28) ^2MPX2 (L17-8) - MPX1 (RJ-21)	Below 1 Ω

Result	Proceed to
Both are OK	A
One is OK	B
Both are NG	C