B1272

MULTIPLEX COMMUNICATION SYSTEM: B1272: Power Seat ECU Communication Stop

DTC B1272 - Power Seat ECU Communication Stop

DESCRIPTION

This DTC is detected when communication between the position control ECU and switch (driver seat ECU) and multiplex network gateway ECU stops for more than 10 seconds.






WIRING DIAGRAM





INSPECTION PROCEDURE
HINT: When "+B or GND short malfunction of communication bus" DTCs (B1214 and B1215) are detected at the same time as "communication stop" DTC B1272, repair the "+B or GND short malfunction of communication bus" DTCs first.

PROCEDURE

1. CHECK OPERATION
(a) Check that the switch of the front power seat can move the driver side seat normally.
HINT: With this inspection, the position control ECU & switch assembly (driver seat ECU) CPU can be diagnosed if it works normally or not.

OK:
Switch of the front power seat can move driver side seat normally.
OK -- CHECK RESISTANCE OF COMMUNICATION LINE
NG -- Continue to next step.
2. INSPECT FUSE (P/SEAT)
(a) Remove the P/SEAT fuse from the instrument panel junction block.
(b) Measure the resistance of the fuse.
Standard resistance:
Below 1 Ohms
NG -- REPLACE FUSE
OK -- Continue to next step.
3. CHECK HARNESS AND CONNECTOR (POSITION CONTROL ECU AND SWITCH - BATTERY AND BODY GROUND)





(a) Disconnect the P33 ECU connector.
(b) Measure the resistance and voltage of the wire harness side connector.
Standard voltage:






Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
4. CHECK RESISTANCE OF COMMUNICATION LINE
(a) Disconnect the P32, P22 and T4 ECU connectors (with Driving position memory).
(b) Disconnect the P32, P22 and G3 ECU connectors (without Driving position memory, without Tire pressure warning system).
(c) Disconnect the P32, P22 and T23 ECU connectors (with Tire pressure warning system, without Driving position memory).





(d) Measure the resistance of the wire harness side connectors.
Standard resistance:





*1: with Driving Position Memory
*2: without Driving Position Memory, without Tire Pressure Warning System
*3: with Tire Pressure Warning System, without Driving Position Memory
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE POSITION CONTROL ECU AND SWITCH ASSEMBLY