Power Source / Network

Sliding Roof ECU Communication Stop (B1273)

~3min read
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
  1. CLEAR DTC

(a) Clear the DTCs (See page ).


NEXT
  1. CHECK FOR DTC

(a) Check for DTCs (See page ).


OK:

DTC B1273 is not output.


OK

USE SIMULATION METHOD TO CHECK

NG
  1. 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.

(c) Disconnect the S10 sliding roof ECU (sliding roof drive gear sub-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


NG

GO TO STEP 8

OK
  1. 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

(c) Measure the voltage according to the value(s) in the table below.

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))


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK
  1. 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
).

NEXT
  1. CLEAR DTC

(a) Clear the DTCs (See page ).


NEXT
  1. CHECK FOR DTC

(a) Check for DTCs (See page ).


OK:

DTC B1273 is not output.


OK

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


NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

  1. 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


OK

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


NG

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY

Test yourself

A quick Toyota 4Runner quiz: every answer comes with an explanation and a link to the manual page.