Lexus IS250 · Service Manual COMMUNICATION SYSTEM

B1296

Diagnostic trouble codes

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
  1. Front controller
  2. Wire harness

WIRING DIAGRAM

B110908E01

INSPECTION PROCEDURE

HINT:
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.


1. INSPECT FUSE (MPX-B)

  1. Remove the MPX-B fuse from the engine room J/B No. 1.

  1. Measure the resistance of the fuse.

    Standard resistance:
    Below 1 Ω



 NG
REPLACE FUSE
OK


Go to step 3

2. CHECK WIRE HARNESS (FRONT CONTROLLER - BATTERY AND BODY GROUND)

  1. B131028E01
    Disconnect the 2E and 2F ECU connectors.

  1. 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



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3. CHECK RESISTANCE OF COMMUNICATION LINE

  1. B131029E01
    Disconnect the 2F, A30 and J55 ECU connectors.

  1. 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



B
REPAIR OR REPLACE HARNESS OR CONNECTOR AND REPLACE FRONT CONTROLLER

C
REPAIR OR REPLACE HARNESS OR CONNECTOR
A

REPLACE FRONT CONTROLLER


← B1289B1297 →