B1266

MULTIPLEX COMMUNICATION: MULTIPLEX COMMUNICATION SYSTEM: B1266: Short to B+ in Instrument Panel System Communication Bus Malfunction

DTC B1266 - Short to B+ in Instrument Panel System Communication Bus Malfunction

DTC B1267 - Short to GND in Instrument Panel System Communication Bus Malfunction

DESCRIPTION

When a +B or body ground short circuit is detected on the instrument panel system communication bus (BEAN), the instrument panel system communication bus (BEAN) is disabled and a DTC is output.






WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK DIAGNOSTIC TROUBLE CODE (A ECU)
(a) Disconnect the A ECU connector and check for DTCs B1266 and B1267.





OK:
DTCs B1266 and B1267 are not output.
NOTICE:
Reconnect the connector before starting the next check.
HINT:
- The A ECU in the instrument panel system bus represents the combination switch (windshield wiper switch).
- If the result is as specified, the disconnected A ECU (combination switch (windshield wiper switch)) is malfunctioning.

NG -- CHECK DIAGNOSTIC TROUBLE CODE (B ECU)
OK -- REPLACE A ECU
2. CHECK DIAGNOSTIC TROUBLE CODE (B ECU)
(a) Disconnect the A ECU and B ECU connectors and check for DTCs B1266 and B1267.





OK:
DTCs B1266 and B1267 are not output.
NOTICE:
Disconnect the connectors one by one. Reconnect the connectors before starting the next check.
HINT:
- The B ECU in the instrument panel system bus represents one of the following: airbag sensor assembly center, A/C amplifier No. 2 cowl side junction block RH, center junction block RH.
- If the result is as specified, the disconnected B ECU (one of the ECUs from the above list) or the wire harness between the A ECU and B ECU is malfunctioning.

NG -- CHECK WIRE HARNESS BETWEEN A ECU AND B ECU
OK -- Continue to next step.
3. CHECK WIRE HARNESS BETWEEN A ECU AND B ECU
(a) Disconnect the B ECU connector and check for DTCs B1266 and B1267.





OK:
DTCs B1266 and B1267 are not output.
NOTICE:
Reconnect the connector before starting the next check.
HINT:
If the result is as specified, the wire harness between the A ECU and B ECU is functioning normally but the disconnected B ECU is malfunctioning.

NG -- REPAIR OR REPLACE WIRE HARNESS BETWEEN A ECU AND B ECU
OK -- REPLACE B ECU
4. CHECK DIAGNOSTIC TROUBLE CODE (C ECU)
(a) Disconnect the B ECU and C ECU connectors and check for DTCs B1266 and B1267.





OK:
DTCs B1266 and B1267 are not output.
NOTICE:
Disconnect the connectors one by one. Reconnect the connectors before starting the next check.
HINT:
- The C ECU in the instrument panel system bus represents the integration control and panel assembly.
- If the result is as specified, the disconnected C ECU (integration control and panel assembly) or the wire harness between the B ECU and C ECU is malfunctioning.

NG -- CHECK WIRE HARNESS BETWEEN GATEWAY ECU AND A ECU OR C ECU
OK -- Continue to next step.
5. CHECK WIRE HARNESS BETWEEN B ECU AND C ECU
(a) Disconnect the C ECU connector and check for DTCs B1266 and B1267.





OK:
DTCs B1266 and B1267 are not output.
NOTICE:
Reconnect the connector before starting the next check.
HINT:
If the result is as specified, the wire harness between the B ECU and C ECU is functioning normally but the disconnected C ECU is malfunctioning.

NG -- REPAIR OR REPLACE WIRE HARNESS BETWEEN B ECU AND C ECU
OK -- REPLACE C ECU
6. CHECK WIRE HARNESS BETWEEN GATEWAY ECU AND A ECU OR C ECU
(a) Check for a short circuit in B+ or body ground.





(1) Disconnect the A ECU, C ECU and gateway ECU connectors.
(2) Measure the resistance and voltage of the wire harness side connectors.
Standard voltage:






Standard resistance:





HINT:
- The A ECU in the instrument panel system bus represents the combination switch (windshield wiper switch).
- The C ECU in the instrument panel system bus represents the integration control and panel assembly.

NG -- REPAIR OR REPLACE WIRE HARNESS BETWEEN GATEWAY ECU AND A ECU OR C ECU
OK -- REPLACE NETWORK GATEWAY ECU