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. 2 junction block (front controller) and 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.
NG -- INSPECT FUSE (MPX-B, D/C CUT)
OK -- REPLACE ENGINE ROOM RELAY BLOCK NO.2 (FRONT CONTROLLER)
2. INSPECT FUSE (MPX-B, D/C CUT)
(a) Remove the MPX-B and D/C CUT fuses 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 (ENGINE ROOM R/B NO. 2 (FRONT CONTROLLER) - BATTERY AND BODY GROUND)




(a) Disconnect the 2F and 2E relay block controllers from the engine room No. 1. relay block, junction block.
(b) Measure the resistance of the wire harness side connectors.
Standard voltage:






Standard resistance:






NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.

4. CHECK RESISTANCE OF COMMUNICATION LINE




(a) Disconnect the K22 switch connector.
(b) Disconnect the A30 or A29* ECU connector.
(c) Disconnect the 2F controller from the engine room relay block No. 2.
(d) Measure the resistance of the wire harness side connectors.
Standard resistance:





HINT: *: w / AFS

Result:






C -- REPAIR OR REPLACE HARNESS AND CONNECTOR
B -- REPLACE ENGINE ROOM RELAY BLOCK NO.2 AND WIRE HARNESS 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 RELAY BLOCK NO.2
OK -- REPLACE FRONT CONTROLLER