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 engine room No. 1 relay block, junction block (front controller) and network gateway ECU stops for more than 10 seconds.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK OPERATION
(a) Turn the headlight dimmer switch ON and check that the headlights illuminate.
OK:
Headlights illuminate.
OK -- REPLACE ENGINE ROOM NO. 1 RELAY BLOCK, JUNCTION BLOCK (FRONT CONTROLLER)
NG -- Continue to next step.
2. INSPECT FUSE (MPX-B)
(a) Remove the MPX-B fuse from the engine room No. 1 relay block, junction block.
(b) Measure the resistance of the fuses.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
3. CHECK WIRE HARNESS (FRONT CONTROLLER - BATTERY AND BODY GROUND)





(a) Disconnect the 1X and 1Y engine room No. 1 junction block connectors.
(b) Measure the voltage and resistance of the wire harness side connectors.
Standard voltage:
Standard resistance










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





(a) Disconnect the K22 switch connector.
(b) Disconnect the A29 ECU connector.
(c) Disconnect the 1X engine room No. 1 junction block connector.
(d) Measure the resistance of the wire harness side connectors.
Standard resistance:






Result





C -- REPAIR OR REPLACE HARNESS OR CONNECTOR
B -- REPAIR OR REPLACE ENGINE ROOM NO. 1 RELAY BLOCK, JUNCTION BLOCK AND WIRE HARNESS OR CONNECTOR
A -- Continue to next step.
5. CHECK OPERATION OF FRONT CONTROLLER
(a) After replacing the front controller with a normally functioning controller, check that the headlights illuminate.
OK:
Headlights illuminate.
NG -- REPLACE ENGINE ROOM NO. 1 RELAY BLOCK, JUNCTION BLOCK
OK -- REPLACE FRONT CONTROLLER