Toyota Sequoia (2005). Manual - part 537

–

DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

DI–1943

2137

DTC

B1271

Combination meter ECU communica-
tion stop

CIRCUIT DESCRIPTION

This DTC is indicated when communication fails between the combination meter and body ECU.

DTC No.

DTC Detecting Condition

Trouble Area

B1271

No communication from combination meter for more than 10

seconds.

Combination meter

Wire harness

Body ECU

DIDFJ–01

I28470

Back Door ECU

Combination Meter

I19
A/C ECU
(Integration Control and Panel)

Instrument Panel J/B

I18
Ignition SW

Engine Room J/B

Instrument Panel J/B

J8
J/C

F10
Fusible
Link Block

Battery

IE

C6

B11

BF1

BD2

J34

J33

C5

C5

C6

1J

1C

1D

1H

1J

1C

2C

2D

2C

1D

1F

C6

Short Pin ECU–B

AM2

IGN1

IG2

AM2

MPX1

MPX–

LG–B

LG–R

LG–R

LG–R

LG–B

W–R

B–O

W–R

B–R

W–R

W–R

W–R

W–R

W–B

BR

B

B

A

B

H

2

31

32

23

24

6

7

13

3

2

9

11

5

6

3

7

1

8

1

9

6

12

5

4

J/C

DI–1944

–

DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

2138

WIRING DIAGRAM

–

DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

DI–1945

2139

INSPECTION PROCEDURE

1

Check combination meter.

CHECK:
Start the engine and check that the speed meter and tachometer operate normally.
HINT:
With this inspection, the combination meter CPU can be diagnosed if it works normally or not.
OK:

Speed meter and tachometer operate normally.

NG

Go to combination system (See page 

DI–1610

).

OK

2

Check wire harness and connector (Combination meter – back door ECU, com-
bination meter – integration control and panel).

PREPARATION:
Disconnect connector ”B11” of the back door ECU, connector ”C5” of the combination meter and connector
”I19” of the integration control and panel.
CHECK:
Measure the resistance according to the values in the table below.
OK:

Tester connection (Symbols)

Condition

Specified condition

B11–2 (MPX1) – C5–31

Always

Below 1 

Ω

I19–13 (MPX–) – C5–32

Always

Below 1 

Ω

B11–2 (MPX1) – Body ground

Always

10 k

Ω 

or higher

I19–13 (MPX–) – Body ground

Always

10 k

Ω 

or higher

NG

Repair or replace wire harness.

OK

Replace the combination meter.

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

DI–1946

–

DIAGNOSTICS

MULTIPLEX COMMUNICATION SYSTEM

2140

DTC

B1272

Memory seat ECU communication stop (w/
Driving position memory)

CIRCUIT DESCRIPTION

This DTC is indicated when communication fails between the memory seat ECU & switch and body ECU.

DTC No.

DTC Detecting Condition

Trouble Area

B1272

No communication from memory seat ECU & switch for more

than 10 seconds.

Memory seat ECU & switch

Wire harness

Body ECU

DIDFK–01