Toyota 4Runner: Sliding Roof ECU Communication Stop (B1273)

Toyota 4Runner Service Manual / Power Source / Network / 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 (multiplex network body ECU) stops for 10 seconds or more.

DTC Code	DTC Detection Condition	Trouble Area
B1273	No communication between the sliding roof ECU (sliding roof drive gear sub-assembly) and main body ECU (multiplex network body ECU) for 10 seconds or more.	Sliding roof ECU (sliding roof drive gear sub-assembly) Driver side junction block assembly Main body ECU (multiplex network body ECU) Harness or connector

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When using the Techstream with the ignition switch off to troubleshoot:
Connect the Techstream to the vehicle and turn a courtesy light switch on and off at 1.5 second intervals until communication between the Techstream and vehicle begins.
Inspect the fuses and bulbs for circuits related to this system before performing the following inspection procedure.

HINT:

When communication between the sliding roof ECU (sliding roof drive gear sub-assembly) and main body ECU (multiplex network body ECU) stops, DTC B2325 is also stored.

PROCEDURE

CLEAR DTC

(a) Clear the DTCs (See page ).

2.	CHECK FOR DTC

(a) Check for DTCs (See page ).

OK:

DTC B1273 is not output.

USE SIMULATION METHOD TO CHECK

3.	CHECK HARNESS AND CONNECTOR (MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) - SLIDING ROOF ECU (SLIDING ROOF DRIVE GEAR SUB-ASSEMBLY))

(a) Remove the main body ECU (multiplex network body ECU) from the driver side junction block assembly (See page ).

(b) Connect the 2B driver side junction block assembly connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A-16 (LIN2) - S10-11 (MPX1)	Always	Below 1 Ω
A-16 (LIN2) or S10-11 (MPX1) - Body ground	Always	10 kΩ or higher

GO TO STEP 8

4.	CHECK HARNESS AND CONNECTOR (SLIDING ROOF ECU (SLIDING ROOF DRIVE GEAR SUB-ASSEMBLY) - BATTERY AND BODY GROUND)

(a) Disconnect the S10 sliding roof ECU (sliding roof drive gear sub-assembly) connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
S10-12 (E) - Body ground	Always	Below 1 Ω

Standard Voltage:

Tester Connection	Switch Condition	Specified Condition
S10-8 (B) - Body ground	Always	11 to 14 V
S10-1 (IG) - Body ground	Ignition switch ON	11 to 14 V

Text in Illustration

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

REPAIR OR REPLACE HARNESS OR CONNECTOR

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

(a) Temporarily replace the sliding roof ECU (sliding roof drive gear sub-assembly) with a new or normally functioning one (See page
).

CLEAR DTC

(a) Clear the DTCs (See page ).

7.	CHECK FOR DTC

(a) Check for DTCs (See page ).

OK:

DTC B1273 is not output.

END (SLIDING ROOF ECU (SLIDING ROOF DRIVE GEAR SUB-ASSEMBLY) IS DEFECTIVE)

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

8.	CHECK DRIVER SIDE JUNCTION BLOCK ASSEMBLY

(a) Remove the main body ECU (multiplex network body ECU) from the driver side junction block assembly (See page ).

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
A-16 (LIN2) - 2B-11	Always	Below 1 Ω
A-16 (LIN2) or 2B-11 - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVER SIDE JUNCTION BLOCK ASSEMBLY - SLIDING ROOF ECU (SLIDING ROOF DRIVE GEAR SUB-ASSEMBLY))

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY

LIN Communication Bus Malfunction (B2325)

DESCRIPTION The main body ECU (multiplex network body ECU) intermittently monitors the LIN communication bus between the components related to the doors and sliding roof ECU (sliding roof drive g ...

Air Conditioning Control Panel does not Operate

DESCRIPTION When a switch of the air conditioning control assembly is operated, the air conditioning control assembly uses LIN communication to communicate with the air conditioning amplifier. If ...

Other materials about Toyota 4Runner:

Auto Up Operation does not Fully Close Power Window (Jam Protection Function is Activated)
DESCRIPTION If any door glass or a power window regulator motor does not operate smoothly, the jam protection function may be triggered automatically, resulting in the auto up function being unable to fully close the window. HINT: This symptom may occur ...

Precaution
PRECAUTION 1. IGNITION SWITCH EXPRESSION HINT: The type of ignition switch used on this model differs depending on the specifications of the vehicle. The expressions listed in the table below are used in this section. Expression Ign ...