Toyota Sequoia (2005). Manual - part 624

I28480

Combination Meter

SPD

G–O

25

C5

3

R29

J17 
J/C

B

Radio and Navigation Assy

B

G–O

–

DIAGNOSTICS

NAVIGATION SYSTEM

DI–2291

2485

Speed signal circuit

CIRCUIT DESCRIPTION

The navigation ECU (built in the radio and navigation assy) receives a vehicle speed signal from the com-
bination meter assy and information about the GPS antenna, and then adjusts vehicle position.
HINT:

A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter. The signal
is changed to a pulse signal at the transistor in the combination meter. Each ECU controls the respec-
tive system based on the pulse signal.

If a short occurs in an ECU, all systems in the speed signal circuit will not operate normally.

WIRING DIAGRAM

DIDDP–01

I28748

SPD

Wire Harness View:

R29

4.5 to 14 V

0

Turn the wheel

Below 2 V

DI–2292

–

DIAGNOSTICS

NAVIGATION SYSTEM

2486

INSPECTION PROCEDURE

1

Check operation of speedometer.

CHECK:
Drive the vehicle and check if the function of the speedometer in the combination meter is normal.
OK:

Actual vehicle speed and the speed indicated on the speedometer and the same.

HINT:
The vehicle speed sensor is functioning normally when the indication on the speedometer is normal.

NG

Check combination meter assy 
(See page 

DI–1645

).

OK

2

Inspect combination meter assy.

PREPARATION:
Disconnect the radio and navigation assy connector.
CHECK:
(a)

Move the shift lever to the neutral position.

(b)

Jack up either one of the front wheels.

(c)

Turn the ignition switch on.

(d)

Measure the voltage between terminal SPD and body
ground of the radio and navigation assy when the front
wheels are turned slowly.

OK:

Voltage is pulses as shown below.

OK

Replace radio and navigation assy.

NG

I28748

Radio and Navigation Assy:

SPD

R29

I28569

Combination Meter Assy:

C5–25

–

DIAGNOSTICS

NAVIGATION SYSTEM

DI–2293

2487

3

Check harness and connector (Combination meter assy – Radio and navigation
assy).

PREPARATION:
Disconnect the radio and navigation assy and combination me-
ter assy connectors.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Tester connection

Condition

Specified condition

SPD (R29–3) – C5–25

Ignition switch OFF

Below 1 

Ω

SPD (R29–3) – 

Body ground

Ignition switch OFF

10 k

Ω 

or higher

HINT:
If the resistance between terminal SPD and body ground is less
than 10 k

Ω

, there may be a short in a wire harness, connector,

or ECU.

NG

Repair or replace harness or connector.

OK

Replace combination meter assy.

I28481

Radio and Navigation Assy

P1 
Park/Neutral Position Switch

Instrument Panel J/B

REV

IG4

J/C

J51

J52

From Ignition 
Switch

R29

IPO

RAD No. 2

1D

1C

RB

RL

L–R

B–Y

5

F

H

L–R

B–Y

L–R

7

1

8

6

9

1

2

DI–2294

–

DIAGNOSTICS

NAVIGATION SYSTEM

2488

Reverse signal circuit

CIRCUIT DESCRIPTION

The radio and navigation assy receives the reverse signal from the park/neutral position switch and informa-
tion about the GPS antenna, and then adjusts the vehicle position.

WIRING DIAGRAM

DIDDQ–01