B1267

MULTIPLEX COMMUNICATION: MULTIPLEX COMMUNICATION SYSTEM: B1266,B1267: Short to B+ in Instrument Panel System Communication Bus Malfunction
B1266 - Short to B+ in Instrument Panel System Communication Bus Malfunction
B1267 - Short to GND in Instrument Panel System Communication Bus Malfunction

DESCRIPTION

When a +B short circuit 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 code 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:

Neither DTC B1266 nor DTC B1267 is output.

NOTICE:
Reconnect the connector before starting the next check.

HINT
* The A ECU in the instrument panel system bus represents the air conditioning amplifier.
* If the result is as specified, the disconnected A ECU (air conditioning amplifier) is malfunctioning.
OK -- REPLACE A ECU
NG -- Continue to next step.

2. CHECK DIAGNOSTIC TROUBLE CODE (B ECU)

(a) Disconnect the A ECU and B ECU connectors and check for DTCs B1266 and B1267.





OK:

Neither DTC B1266 nor DTC B1267 is output.

NOTICE:
Disconnect the connectors one by one. Reconnect the connectors before starting the next check.

HINT
* Remove the B ECUs in the following order:
* AFS ECU
* Clearance warning ECU
* Combination meter ECU
* 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.
* After the DTC is cleared, proceed to the next step.
NG -- CHECK DIAGNOSTIC TROUBLE CODE (C 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:

Neither DTC B1266 nor DTC B1267 is 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:

Neither DTC B1266 nor DTC B1267 is 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 tire pressure warning ECU.
* If the result is as specified, the disconnected C ECU (tire pressure warning ECU) 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:

Neither DTC B1266 nor DTC B1267 is 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 multiplex network 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 air conditioning amplifier.
* The C ECU in the instrument panel system bus represents the tire pressure monitor ECU.
NG -- REPAIR OR REPLACE WIRE HARNESS BETWEEN GATEWAY ECU AND A ECU OR C ECU

OK -- REPLACE MULTIPLEX NETWORK GATEWAY ECU