Toyota Venza: Sliding Roof ECU Communication Stop (B1273)

Toyota Venza Service Manual / Networking / Lin Communication System / Sliding Roof ECU Communication Stop (B1273)

DESCRIPTION

This DTC is stored when LIN communication between the sliding roof ECU (sliding roof drive gear sub-assembly) and main body ECU (driver side junction block assembly) stops for more than 10 seconds.

DTC No.	DTC Detection Condition	Trouble Area
B1273	No communication between the sliding roof ECU (sliding roof drive gear sub-assembly) and main body ECU (driver side junction block assembly) for more than 10 seconds.	Sliding roof ECU (Sliding roof drive gear sub-assembly) Main body ECU (Driver side junction block assembly) Wire harness or connector S/ROOF fuse

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When the sliding roof ECU (sliding roof drive gear sub-assembly) is replaced or removed and reinstalled, it requires initialization (See page ).

When using the Techstream to troubleshoot with the ignition switch off:
Connect the Techstream to the DLC3, and turn the courtesy switch on and off at 1.5-second intervals until communication between the Techstream and vehicle begins.

PROCEDURE

1.	CHECK HARNESS AND CONNECTOR (SLIDING ROOF ECU - BATTERY AND BODY GROUND)

(a) Disconnect the P4 ECU connector.

(b) Measure the resistance and voltage according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
P4-2 (E) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Condition	Specified Condition
P4-1 (B) - Body ground	Always	11 to 14 V

Text in Illustration

*1	Front view of wire harness connector (to Sliding Roof ECU (Sliding Roof Drive Gear Sub-assembly))

REPAIR OR REPLACE HARNESS OR CONNECTOR

2.	CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - SLIDING ROOF ECU)

(a) Disconnect the D48 ECU connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
D48-10 (LIN2) - P4-4 (LIN)	Always	Below 1 Ω
P4-4 (LIN) - Body ground	Always	10 kΩ or higher

Text in Illustration

Front view of wire harness connector

(to Main Body ECU (Driver Side Junction Block Assembly))

Front view of wire harness connector

(to Sliding Roof ECU (Sliding Roof Drive Gear Sub-assembly))

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	REPLACE SLIDING ROOF ECU (SLIDING ROOF DRIVE GEAR SUB-ASSEMBLY)

(a) Replace the sliding roof ECU (sliding roof drive gear sub-assembly) (See page ).

4.	CHECK DTC OUTPUT

(a) Clear the DTC (See page ).

(b) Recheck for DTCs.

OK:

DTC B1273 is not output.

END (SLIDING ROOF ECU WAS DEFECTIVE)

REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY)

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