DTC B1209 Driver Side Outer Mirror

DESCRIPTION

This DTC is detected when communication between the outer mirror control ECU (driver side outer mirror ECU) and gateway ECU stops for more than 10 seconds.

DTC No.	DTC Detection Condition	Trouble Area
B1209	Outer mirror control ECU (driver side) Communication stops	Outer mirror control ECU LH (driver side) Wire harness

WIRING DIAGRAM

Dtc B1209 Driver Side Outer Mirror. 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 B1209, repair the "+B or GND short malfunction of communication bus" DTCs first.

1.INSPECT FUSE (FR DOOR LH (LHD), FR DOOR RH (RHD), MPX-B)

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

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

Remove the MPX-B fuse from the engine room J/B No. 1.

Measure the resistance of the fuse.

Standard resistance:
Below 1 Ω

NG

REPLACE FUSE

OK

2.CHECK HARNESS AND CONNECTOR (OUTER MIRROR CONTROL ECU - BATTERY AND BODY GROUND)

Disconnect the M10 ECU connector (for LHD).

Dtc B1209 Driver Side Outer Mirror. MULTIPLEX COMMUNICATION. Lexus IS250 IS220d GSE20 ALE20

Disconnect the L10 ECU connector (for RHD).

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

Standard voltage:
Tester Connection Condition Specified Condition
^*1BDR (M10-6) - Body ground
^*2BDR (L10-6) - Body ground Always 10 to 14 V

Standard resistance:
Tester Connection Specified Condition
^*1GND (M10-1) - Body ground
^*2GND (L10-1) - Body ground Below 1 Ω

HINT:

*1: LHD

*2: RHD

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.CHECK RESISTANCE OF COMMUNICATION LINE

Disconnect the M10 and J55 ECU connectors (for LHD).

Disconnect the L10 and P33 ECU connectors (for RHD).

Dtc B1209 Driver Side Outer Mirror. 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 (M10-8) - MPX2 (J55-24)
^*1MPX1 (L10-8) - MPX1 (P33-27) Below 1 Ω
^*1MPX1 (M10-8) - Body ground
^*1MPX1 (L10-8) - Body ground Below 1 Ω

HINT:

*1: LHD

*2: RHD

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

REPLACE OUTER MIRROR CONTROL ECU (DRIVER SIDE)

LEXUS IS250, IS220d / GSE20 ALE20

MULTIPLEX COMMUNICATION

Lexus IS250 IS220d GSE20 ALE20

MULTIPLEX COMMUNICATION SYSTEM

Tester Connection	Condition	Specified Condition
^1BDR (M10-6) - Body ground ^2BDR (L10-6) - Body ground	Always	10 to 14 V

Tester Connection	Specified Condition
^1GND (M10-1) - Body ground ^2GND (L10-1) - Body ground	Below 1 Ω

Tester Connection	Specified Condition
^1MPX1 (M10-8) - MPX2 (J55-24) ^1MPX1 (L10-8) - MPX1 (P33-27)	Below 1 Ω
^1MPX1 (M10-8) - Body ground ^1MPX1 (L10-8) - Body ground	Below 1 Ω