Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM0000017WW005X
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: MULTIPLEX COMMUNICATION: MULTIPLEX COMMUNICATION SYSTEM: B1272; Power Seat ECU Communication Stop; 2007 MY LX470 [08/2006 -        ]

DTC

B1272

Power Seat ECU Communication Stop

DESCRIPTION

HINT:

"Power seat ECU" refer to the position control ECU (driver seat ECU).

  • This DTC is output when communication between the position control ECU (driver seat ECU) and multiplex network body ECU (main).

DTC No.

DTC Detection Condition

Trouble Area

B1272

No signal from position control ECU assembly (Driver seat ECU) for more than 10 seconds.
  • Position control ECU assembly (Driver seat ECU)
  • Wire harness

WIRING DIAGRAM

  • Refer to DTC B1214 and 1215 2007 MY LX470 [08/2006 -        ]; MULTIPLEX COMMUNICATION: MULTIPLEX COMMUNICATION SYSTEM: B1214,B1215; Short to B+ in Door System Communication Bus Malfunction+ .

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK POSITION CONTROL ECU ASSEMBLY (DRIVER SEAT ECU)

(a) Check that the seat's front vertical and rear vertical operations are normal.

HINT:

With this inspection, whether or not the position control ECU (driver seat ECU) CPU functions normally can be diagnosed.

NG

REPLACE POSITION CONTROL ECU ASSEMBLY (DRIVER SEAT ECU)

OK

2.

CHECK WIRE HARNESS (POSITION CONTROL ECU ASSEMBLY - MULTIPLEX NETWORK BODY ECU (MAIN) AND MIRROR CONTROL ECU)

(a) Disconnect the ECU connectors mentioned in the table below.

(b) Check the continuity of the wire harness between the connectors.

Wire harness side connector of ECU

Terminal

Position control ECU assembly (Driver seat ECU) - Multiplex network body ECU (Main)

S28-4 (MPX1) - B7-23 (MPX2)

Position control ECU assembly (Driver seat ECU) - Outer mirror control ECU

S28-9 (MPX2) - R30-25 (MPX1)

OK:

There is continuity between the connectors.

HINT:

If there is an open in any wire harness, repair it.

NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

REPLACE POSITION CONTROL ECU ASSEMBLY (DRIVER SEAT ECU)