Toyota Sequoia (2005). Manual - part 529

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DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

DI–1911

2105

DTC

B1212

Front passenger door ECU commu-
nication stop

CIRCUIT DESCRIPTION

This DTC is indicated when communication fails between the passenger door ECU and body ECU.

DTC No.

DTC Detecting Condition

Trouble Area

B1212

No communication from passenger door ECU for more than 10

Passenger door ECU

Wi

h

B1212

No communication from  assenger door ECU for more than 10

seconds.

Wire harness

Body ECU

DIDFC–01

I28468

MPX2

MPX1

D22
Driver Door ECU

Back Door ECU

IB1

F18
Passenger 
Door ECU

J/C

II2

BF1

BD2

B11

J37

J38

J/C

J34

J33

II2

II2

MPX2

MPX1

SIG

BDR

GND

F18 F18

F18 F18

F18 F18

F18 F18

F18 F18

F18 F18

G–B

B

B–R

G–B

G–B

B

B

B

B

B–R

B–R

B–R

B–Y

W–L

L–Y

L–Y

B

W–R

W–R

W–R

W–R

W–B

A

J12
J/C

Battery

IF

II2

II2

Sub J/B No. 3

3D

3A

1

1

6

11

13

8

(*1)

(*2)

23

12

(*1)

(*2)

25

20

(*1)

(*2)

21

19

(*1)

(*2)

20

10

(*1)

(*2)

8

11

(*1)

(*2)

Engine Room J/B

ECU–B

Short Pin

2D

2C

1

8

Instrument Panel J/B

1E

1J

2

3

II2

F10
Fusible Link Block

ALT

4

8

5

Instrument Panel J/B

ECU–IG

AM1

PWR No. 2

1F

1C

1L

1C

1F

4

4

1

17

6

1

2

Sub J/B No. 3

3C

3A

8

8

I18
Ignition SW

IG1

AM1

4

8

8

2

1

14

A

G

2

7

(*1): w/ Driving Position Memory
(*2): w/o Driving Position Memory

20

A

A

3

B

1

W–B

CPUB

W

DI–1912

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DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

2106

WIRING DIAGRAM

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DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

DI–1913

2107

INSPECTION PROCEDURE

1

Check passenger door ECU.

CHECK:
Check if the passenger door window glass auto up function operates normally through the front passenger
door window switch.
HINT:
With this inspection, the passenger door ECU CPU can be diagnosed if it works normally or not.
OK:

Front passenger side power window auto up function operates normally.

NG

Go to power source circuit (See page 

DI–1826

).

OK

2

Check wire harness and connector (Passenger door ECU – driver door ECU,
back door ECU).

PREPARATION:
Disconnect connector ”D22” of the driver door ECU, ”F18” of the passenger door ECU and ”B11” of the back
door ECU.
CHECK:
Measure the resistance according to the values in the table below.
OK:

Symbols (Tester connection)

Condition

Specified condition

MPX1 (D22–20) – MPX2 (F18–8) (*1)

Always

Below 1 

Ω

MPX1 (D22–20) – MPX2 (F18–11) (*2)

Always

Below 1 

Ω

MPX2 (B11–1) – MPX1 (F18–20) (*1)

Always

Below 1 

Ω

MPX2 (B11–1) – MPX1 (F18–10) (*2)

Always

Below 1 

Ω

MPX1 (D22–20) – Body ground

Always

10 k

Ω 

or higher

MPX1 (B11–1) – Body ground

Always

10 k

Ω 

or higher

*1: w/ Driving Position Memory
*2: w/o Driving Position Memory

NG

Repair or replace wire harness.

OK

Replace the passenger door ECU.

If the problem reoccurs even after replacement, replace the body ECU.

DI–1914

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DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

2108

DTC

B1214

Communication bus malfunction
(Short to B+)

DTC

B1215

Communication bus malfunction
(Short to ground)

CIRCUIT DESCRIPTION

DTC B1214 or B1215 is detected when a short to +B or short to ground occurs on the multiplex communica-
tion bus (BEAN). Detecting this condition will disable the multiplex communication bus (BEAN) and output
the corresponding DTC.

DTC NO.

DTC detecting condition

Trouble area

B1214

Short to B+ in multiplex communication system communica-

tion circuit

Driver door ECU

Passenger door ECU

Back door ECU

A/C ECU (Integration control panel)

Combination meter

Memory seat ECU & switch

Wire harness

Body ECU

B1215

Short to ground in multiplex communication system commu-

nication circuit

Driver door ECU

Passenger door ECU

Back door ECU

A/C ECU (Integration control panel)

Combination meter

Memory seat ECU & switch

Wire harness

Body ECU

DI94Y–07