Page 2489 of 4323
I28479
Steering
Pad Switch
Spiral Cable
Sub±assyRadio and Navigation Assy
SW2
SWG SW1 R27
EAUAU2
AU1
EAUAU2
AU1C9±11 GR±R
LG±R
BR±W C9±12
C9±10 11
12
108
7
6 R27
R27
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2287
2481 Author: Date:
2005 SEQUOIA (RM1146U)
Steering pad switch circuit
CIRCUIT DESCRIPTION
This circuit sends an operation signal from the steering pad switch assy to the radio and navigation assy.
If there is an open in the circuit, the audio system cannot be operated by the steering pad switch assy.
If there is a short in the circuit, the resulting condition is the same as if the switch were continuously de-
pressed. Therefore, the radio and navigation assy cannot be operated by the steering pad switch assy, and
the radio and navigation assy itself cannot function.
WIRING DIAGRAM
DIDDO±01
Page 2490 of 4323

I28299SW1 SW2SWG
R27
DI±2288
± DIAGNOSTICSNAVIGATION SYSTEM
2482 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
NOTICE:
The vehicle is equipped with SRS (Supplemental Restraint System) such as airbags. Before servic-
ing (including removal or installation of parts), be sure to read the precautionary notice for the sup-
plemental restraint system (See page RS±1).
1 Inspect radio and navigation assy.
PREPARATION:
Disconnect the radio and navigation assy connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Symbol
(Tester connection)ConditionSpecified condition
SW1 (R27±7) ±
SWG (R27±6)No switch is pushedApprox. 100 kW
SW1 (R27±7) ±
SWG (R27±6)SEEK+ switch: pushApprox. 0 W
SW1 (R27±7) ±
SWG (R27±6)SEEK± switch: pushApprox. 0.3 kW
SW1 (R27±7) ±
SWG (R27±6)VOL+ switch: pushApprox. 1 kW
SW1 (R27±7) ±
SWG (R27±6)VOL± switch: pushApprox. 3.2 kW
SW2 (R27±8) ±
SWG (R27±6)No switch is pushedApprox. 100 kW
SW2 (R27±8) ±
SWG (R27±6)MODE switch: pushApprox. 0 W
NG Go to step 2.
OK
Proceed to next circuit inspection shown in problem symptoms table (See page DI±2184).
Page 2491 of 4323
I28724
EAUAU2AU1
C9
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2289
2483 Author: Date:
2005 SEQUOIA (RM1146U)
2 Inspect steering pad switch assy.
PREPARATION:
Disconnect the steering pad switch assy connector.
CHECK:
Measure the resistance according to the value(s) in the table below.
OK:
Symbol (Tester connection)ConditionSpecified condition
AU1 (C9±12) ± EAU (C9±10)No switch is pushedApprox. 100 kW
AU1 (C9±12) ± EAU (C9±10)SEEK+ switch: pushApprox. 0 W
AU1 (C9±12) ± EAU (C9±10)SEEK± switch: pushApprox. 0.3 kW
AU1 (C9±12) ± EAU (C9±10)VOL+ switch: pushApprox. 1 kW
AU1 (C9±12) ± EAU (C9±10)VOL± switch: pushApprox. 3.2 kW
AU2 (C9±11) ± EAU (C9±10)No switch is pushedApprox. 100 kW
AU2 (C9±11) ± EAU (C9±10)MODE switch: pushApprox. 0 W
NG Replace steering pad switch assy.
OK
Page 2492 of 4323
I28340
Steering Pad Switch Assy Side:
EAUAU2
AU1
Vehicle Side:
EAUAU2
AU1
C9
DI±2290
± DIAGNOSTICSNAVIGATION SYSTEM
2484 Author: Date:
2005 SEQUOIA (RM1146U)
3 Inspect spiral cable sub±assy.
PREPARATION:
Disconnect the steering pad switch assy and spiral cable sub±
assy connectors.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Tester connectionSpecified condition
EAU ± EAUBelow 1 W
AU1 ± AU1Below 1 W
AU2 ± AU2Below 1 W
NG Replace spiral cable sub±assy.
OK
Repair or replace harness or connector (Radio and navigation assy ± spiral cable).
Page 2493 of 4323
I28480
Combination Meter
SPD G±O 25
C53
R29 J17
J/C
BRadio and Navigation Assy
BG±O
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2291
2485 Author: Date:
2005 SEQUOIA (RM1146U)
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
Page 2494 of 4323

I28748SPD
Wire Harness View:
R29
4.5 to 14 V
0
Turn the wheel Below 2 V
DI±2292
± DIAGNOSTICSNAVIGATION SYSTEM
2486 Author: Date:
2005 SEQUOIA (RM1146U)
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
Page 2495 of 4323
I28748
Radio and Navigation Assy:
SPD
R29
I28569
Combination Meter Assy:
C5±25
± DIAGNOSTICSNAVIGATION SYSTEM
DI±2293
2487 Author: Date:
2005 SEQUOIA (RM1146U)
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 connectionConditionSpecified condition
SPD (R29±3) ± C5±25Ignition switch OFFBelow 1 W
SPD (R29±3) ±
Body groundIgnition switch OFF10 kW or higher
HINT:
If the resistance between terminal SPD and body ground is less
than 10 kW, there may be a short in a wire harness, connector,
or ECU.
NG Repair or replace harness or connector.
OK
Replace combination meter assy.
Page 2496 of 4323
I28481
Radio and Navigation Assy
P1
Park/Neutral Position Switch
Instrument Panel J/BREV
IG4J/C
J51 J52
From Ignition
SwitchR29
IPORAD No. 2
1D 1CRB
RL L±R B±Y5 FH
L±R B±Y
L±R7
1
8
6 9
1 2 DI±2294
± DIAGNOSTICSNAVIGATION SYSTEM
2488 Author: Date:
2005 SEQUOIA (RM1146U)
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