DESCRIPTION
WIRING DIAGRAM
INSPECTION PROCEDURE
INSPECT FUSE (MPX-B)
CHECK WIRE HARNESS (FRONT CONTROLLER - BATTERY AND BODY GROUND)
CHECK RESISTANCE OF COMMUNICATION LINE
DTC B1296 Front Light ECU Communication Stop
DESCRIPTION
This DTC is detected when communication between the front controller and gateway ECU stops for more than 10 seconds.
| DTC No. | DTC Detection Condition | Trouble Area |
| B1296 | Front controller communication stops | Front controller
Wire harness
|
WIRING DIAGRAM
INSPECTION PROCEDURE
- When "+B of GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1296, repair the "+B or GND short malfunction of communication bus" DTCs first.
Remove the MPX-B fuse from the engine room J/B No. 1.
Measure the resistance of the fuse.
- Standard resistance:
- Below 1 Ω
| 2.CHECK WIRE HARNESS (FRONT CONTROLLER - BATTERY AND BODY GROUND) |
Disconnect the 2E and 2F ECU connectors.
Measure the voltage and resistance of the wire harness side connectors.
- Standard voltage:
| Tester Connection | Condition | Specified Condition |
| 2E-4 - Body ground | Always | 10 to 14 V |
- Standard resistance:
| Tester Connection | Specified Condition |
| 2F-1 - Body ground | Below 1 Ω |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
| 3.CHECK RESISTANCE OF COMMUNICATION LINE |
Disconnect the 2F, A30 and J55 ECU connectors.
Measure the resistance between the specified terminals on the wire harness side connectors.
- Standard resistance:
| Tester Connection | Specified Condition |
| 2F-6 - MPX2 (A30-17) | Below 1 Ω |
| 2F-5 - MPX2 (J55-24) | Below 1 Ω |
- Result:
| Result | Proceed to |
| Both are OK | A |
| One is OK | B |
| Both are NG | C |
| | REPAIR OR REPLACE HARNESS OR CONNECTOR AND REPLACE FRONT CONTROLLER |
|
|
| | REPAIR OR REPLACE HARNESS OR CONNECTOR |
|
|
LEXUS IS250, IS220d / GSE20 ALE20
