B1296

MULTIPLEX COMMUNICATION: MULTIPLEX COMMUNICATION SYSTEM: B1296: Front Light ECU Communication Stop

DTC B1296 - Front Light ECU Communication Stop

DESCRIPTION

This DTC is detected when communication between the multiplex network front light ECU and network gateway ECU stops for more than 10 seconds.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK OPERATION (DIMMER SWITCH)
(a) Turn the dimmer switch ON and check that the headlights illuminate.
OK:
Headlights illuminate.
OK -- REPLACE MULTIPLEX NETWORK FRONT LIGHT ECU
NG -- Continue to next step.
2. INSPECT FUSE (MPX-B3)
(a) Remove the MPX-B3 fuse from the passenger side junction block.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
3. CHECK WIRE HARNESS (MULTIPLEX NETWORK FRONT LIGHT ECU - BATTERY AND BODY GROUND)




(a) Measure the voltage and resistance of the wire harness side connectors.
NOTE:
The inspection should be performed from the backside of the relay block with the multiplex network front light ECU connector connected.

Standard voltage:






Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
4. CHECK RESISTANCE OF COMMUNICATION LINE




(a) Remove the front light ECU from the engine room No. 2 relay block.
(b) Disconnect the A31 and G3 ECU connectors.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:






Result





C -- REPAIR OR REPLACE HARNESS AND CONNECTOR
B -- REPLACE MULTIPLEX NETWORK FRONT LIGHT ECU AND REPAIR OR REPLACE HARNESS AND CONNECTOR
A -- REPLACE MULTIPLEX NETWORK FRONT LIGHT ECU