Toyota Sequoia (2005). Manual - part 450

I24831

Transponder Key ECU

Sub J/B No. 3

+B

J43
J/C

5

1

O

Battery

F10
FL Block

W–R

B

4

IG

B

Engine Room J/B

W–R

3

2

1J

1E

Instrument Panel J/B

A

A

GND

O

14

T16

T16

1

2

W–R

3A

3B

8

1

2C

2D

ECU–B

SHORT PIN

–

DIAGNOSTICS

ENGINE IMMOBILISER SYSTEM

DI–1595

1789

Power source circuit

CIRCUIT DESCRIPTION

This circuit provides power to operate the transponder key ECU.

WIRING DIAGRAM

DI7TO–07

DI–1596

–

DIAGNOSTICS

ENGINE IMMOBILISER SYSTEM

1790

INSPECTION PROCEDURE

1

Check ECU–B fuse.

CHECK:
Check for continuity of the ECU–B fuse.
OK:

Continuity

NG

Replace fuse.

OK

2

Check voltage between terminals +B and GND of transponder key ECU connec-
tor.

PREPARATION:
(a)

Turn the ignition switch OFF.

(b)

Disconnect the transponder key ECU connector.

CHECK:
Measure the voltage between terminals +B and GND.
OK:

Voltage: 10 to 14 V

OK

Proceed to next circuit inspection shown in
problem symptoms table (See page 

DI–1573

).

NG

3

Check wire harness and connector between terminal GND of transponder key
ECU and body ground (See page 

IN–35

).

NG

Repair or replace wire harness or connector.

OK

Check and repair wire harness and connec-
tor between transponder key ECU and bat-
tery.

I24835

Instrument Panel J/B

6

9

BR

1F

1D

W–B

A

IE

J8
J/C

12

C6

C5

16

LG–B

7

T16 IND

Combination Meter

Transponder Key ECU

Security

–

DIAGNOSTICS

ENGINE IMMOBILISER SYSTEM

DI–1597

1791

Security Indicator Light Circuit

CIRCUIT DESCRIPTION

When the transponder key is registered, the transponder key ECU outputs the key registration condition by
illuminating, blinking or turning off the security indicator.

WIRING DIAGRAM

DIABJ–03

I24836

ON

IND

(–)

(+)

DI–1598

–

DIAGNOSTICS

ENGINE IMMOBILISER SYSTEM

1792

INSPECTION PROCEDURE

1

Check voltage between terminal IND of transponder key ECU connector and
body ground.

PREPARATION:
Turn the ignition switch to the ON position and enter diagnosis
mode.
CHECK:
Measure the voltage between terminal IND of the transponder
key ECU connector and body ground when the security indica-
tor light is on and when it is off.
OK:

Indicator light

Voltage

ON

3 to 6 V

OFF

Below 1 V

NG

Proceed to next circuit inspection shown in
problem symptoms table (See page 

DI–1573

).

OK

2

Check combination meter (See page 

DI–1610

).

NG

Replace combination meter.

OK

Check and replace wire harness and connec-
tor (See page 

IN–35

).