B1291

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MULTIPLEX COMMUNICATION: MULTIPLEX COMMUNICATION SYSTEM: B1291: Short to B+ in Light System Communication Bus Malfunction

DTC B1291 - Short to B+ in Light System Communication Bus Malfunction

DTC B1292 - Short to GND in Light System Communication Bus Malfunction

DESCRIPTION

DTC B1291 is detected when +B is short-circuited on the light system (steering column bus) communication bus, and DTC B1292 is detected when the body ground is short-circuited on the light system (steering column bus) communication bus. Detecting this condition will disable the light system communication bus (BEAN) and a DTC will be output.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK LUGGAGE ROOM JUNCTION BLOCK ECU




(a) Disconnect the luggage room junction block ECU connector and check for DTCs B1291 and B1292.






B -- REPLACE LUGGAGE ROOM JUNCTION BLOCK ECU
A -- Continue to next step.
2. CHECK MULTIPLEX NETWORK FRONT LIGHT ECU




(a) Disconnect the engine room No. 2 relay block (multiplex network front light ECU) connector and check for DTCs B1291 and B1292.

Result





B -- REPLACE MULTIPLEX NETWORK FRONT LIGHT ECU
A -- Continue to next step.
3. CHECK WIRE HARNESS (MULTIPLEX NETWORK FRONT LIGHT ECU - LUGGAGE ROOM JUNCTION BLOCK ECU)




(a) Disconnect the luggage room junction block ECU and multiplex network front light ECU connectors, and check for DTCs B1291 and B1292.

Result





B -- CHECK TURN SIGNAL SWITCH ASSEMBLY (COMBINATION SWITCH)
A -- Continue to next step.
4. CHECK WIRE HARNESS CONNECTED TO NETWORK GATEWAY ECU




(a) Disconnect the engine room No. 2 relay block (front light ECU) connector.
(b) Disconnect the G3 and L24 ECU connectors.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






NG -- INSPECT PASSENGER SIDE JUNCTION BLOCK
OK -- REPLACE NETWORK GATEWAY ECU
5. CHECK TURN SIGNAL SWITCH ASSEMBLY (COMBINATION SWITCH)




(a) Disconnect the turn signal switch connector and check for DTCs B1291 and B1292.






B -- REPLACE TURN SIGNAL SWITCH ASSEMBLY (COMBINATION SWITCH)
A -- Continue to next step.
6. CHECK WIRE HARNESS (TURN SIGNAL SWITCH - LUGGAGE ROOM JUNCTION BLOCK ECU)




(a) Disconnect the luggage room junction block ECU and turn signal switch connectors, and check for DTCs B1291 and B1292.






B -- REPAIR OR REPLACE HARNESS AND CONNECTOR
A -- Continue to next step.
7. CHECK MULTIPLEX TILT & TELESCOPIC ECU




(a) Disconnect the multiplex tilt & telescopic ECU connector and check for DTCs B1291 and B1292.






B -- REPLACE MULTIPLEX TILT & TELESCOPIC ECU
A -- Continue to next step.
8. CHECK WIRE HARNESS (TURN SIGNAL SWITCH - MULTIPLEX TILT & TELESCOPIC ECU)




(a) Disconnect the turn signal switch and multiplex tilt & telescopic ECU connectors, and check for DTCs B1291 and B1292.






B -- REPAIR OR REPLACE HARNESS AND CONNECTOR
A -- Continue to next step.
9. CHECK STEERING PAD SWITCH MODULATOR (STEERING PAD SWITCH)




(a) Disconnect the steering pad switch modulator connector and check for DTCs B1291 and B1292.






B -- REPLACE STEERING PAD SWITCH MODULATOR (STEERING PAD SWITCH)
A -- Continue to next step.
10. CHECK WIRE HARNESS (DRIVER SIDE JUNCTION BLOCK ECU - STEERING PAD SWITCH)




(a) Disconnect the driver side junction block ECU and steering pad switch modulator connectors, and check for DTCs B1291 and B1292.






B -- REPAIR OR REPLACE HARNESS AND CONNECTOR
A -- Continue to next step.
11. CHECK DRIVER SIDE JUNCTION BLOCK (DRIVER SIDE JUNCTION BLOCK ECU)




(a) Disconnect the driver side junction block ECU connectors and check for DTCs B1291 and B1292.






B -- REPLACE DRIVER SIDE JUNCTION BLOCK ECU
A -- Continue to next step.
12. CHECK WIRE HARNESS (DRIVER SIDE JUNCTION BLOCK ECU - MULTIPLEX TILT & TELESCOPIC ECU)




(a) Disconnect the driver side junction block ECU and multiplex tilt & telescopic ECU connectors, and check for DTCs B1291 and B1292.






B -- REPAIR OR REPLACE HARNESS AND CONNECTOR
A -- Continue to next step.
13. CHECK AFS ECU




(a) Disconnect the AFS ECU connector and check for DTCs B1291 and B1292.






B -- REPLACE AFS ECU
A -- Continue to next step.
14. CHECK WIRE HARNESS (DRIVER SIDE JUNCTION BLOCK ECU - AFS ECU)




(a) Disconnect the driver side junction block ECU and AFS ECU connectors, and check for DTCs B1291 and B1292.






B -- REPAIR OR REPLACE HARNESS AND CONNECTOR (DRIVER SIDE JUNCTION BLOCK ECU - AFS ECU)
A -- REPAIR OR REPLACE HARNESS AND CONNECTOR (MULTIPLEX NETWORK FRONT LIGHT ECU - AFS ECU)
15. INSPECT PASSENGER SIDE JUNCTION BLOCK
(a) Disconnect the 3C and 3E connectors from the passenger side junction block.




(b) Measure the resistance of the junction block connectors.
Standard resistance:






NG -- REPLACE PASSENGER SIDE JUNCTION BLOCK
OK -- REPAIR OR REPLACE HARNESS AND CONNECTOR