Page 937 of 4323
F16806
High (45°)Low (±45°)
Normal (0°)
Connector Front View:
SHG SHRLSHB
± DIAGNOSTICSAIR SUSPENSION SYSTEM
DI±735
929 Author: Date:
2005 SEQUOIA (RM1146U)
5 Inspect height control sensor sub±assy.
PREPARATION:
(a) Remove the height control sensor sub±assy.
(b) Connect 3 dry batteries of 1.5 V in series.
CHECK:
Connect terminal 1 (SHB) to the batteries' positive (+) terminal,
and terminal 3 (SHG) to the batteries' negative (±) terminal,
then apply approximately 4.5 V between terminals 2 (SHRL)
and 3 (SHG) in the following conditions.
OK:
PositionVoltage
High (0 to 45)Approx. 2.25 to 4.05 V
Normal (0)Approx. 2.25 V
Low (0 to ±45)Approx. 0.45 to 2.25 V
NG Replace height control sensor sub±assy.
OK
Replace suspension control ECU
(See page IN±35).
Page 938 of 4323

F19442
Suspension Control ECU H16
Gate Solenoid Valve
(Height Control Valve)
W±L8
BM1SLRL 114
IN14
S25
BI W±B 2W±LW±L DI±736
± DIAGNOSTICSAIR SUSPENSION SYSTEM
930 Author: Date:
2005 SEQUOIA (RM1146U)
DTC C1733/33 Gate Solenoid Valve Circuit
CIRCUIT DESCRIPTION
The suspension control ECU opens the gate solenoid valve (height control valve) to lead the compressed
air to the height control cylinder (pneumatic cylinder) and to raise the vehicle height.
Further, the gate solenoid valve (height control valve) opens and closes the passage between the right and
left height control cylinders (pneumatic cylinders).
The height control valve consists of a leveling solenoid valve and a gate solenoid valve.
The gate solenoid valve opens and closes the passage between the compressor and the height control cylin-
der (pneumatic cylinder).
DTC No.DTC Detecting ConditionTrouble Area
C1733/33
Either of the following conditions is detected:
1. With the height control valve inactivated, an open signal of
the height control valve is detected for 1 sec. or more.
2. With the height control valve activated, a short signal of the
valve is detected 8 times successively.
Gate solenoid valve (Height control valve)
Gate solenoid valve (Height control valve) circuit
Suspension control ECU
HINT:
Once the ECU stores DTC C1733/33 in the memory, the vehicle height control is suspended until a
normal signal is input to the ECU from the height control solenoid valves. However, control is resumed
if the ignition switch is turned OFF, then ON again.
Malfunction in the gate solenoid valve:
The height control operation is suspended, and the height control indicator lamp does not change by
operating the height control switch.
WIRING DIAGRAM
DIDDN±01
Page 939 of 4323

± DIAGNOSTICSAIR SUSPENSION SYSTEM
DI±737
931 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
If DTC C1761/61 (ECU malfunction) and/or C1774/74 (power source circuit) is displayed, perform the
inspection necessary for DTC C1761/61 (See page DI±761) and/or C1774/74 (See page DI±763) first.
(If DTC C1761/61 and the C1774/74 are output at the same time, perform the inspection necessary
for DTC C1774/74 first.)
Start the inspection from step 1 when using the hand±held tester, and start from step 2 when not using
the hand±held tester.
1 Perform active test using hand±held tester.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON, and push the hand±held tester main switch ON.
(c) Select the item ºGATE SOL REARº in the ACTIVE TEST, and operate it with the hand±held tester.
AIR SUSPENSION:
ItemVehicle Condition / Test DetailsDiagnostic Note
GATE SOL REARTurn gate solenoid valve / ON or OFFOperation sound of solenoid (clicking sound) can
be heard
CHECK:
(a) Check whether the solenoid makes sound.
(b) Check whether the height control valve has continuity (will vibrate).
OK:
The solenoid makes sound, and the height control valve has continuity (will vibrate).
RESULT:
NGA
OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE)B
OK (When troubleshooting according to the DTC chart)C
B Proceed to next circuit inspection shown in
problem symptoms table (See page DI±716).
C Replace suspension control ECU
(See page IN±35).
A
Page 940 of 4323
F19437
Connector Front View:
32 1
DI±738
± DIAGNOSTICSAIR SUSPENSION SYSTEM
932 Author: Date:
2005 SEQUOIA (RM1146U)
2 Inspect gate solenoid valve (height control valve).
PREPARATION:
Disconnect the valve connector.
CHECK:
Measure the resistance between terminals.
OK:
Solenoid valveTester connectionResistance
Gate solenoid valve1 ± 217.5 to 21.5 W
CHECK:
Check the operating sound of the valves when battery voltage
is applied to the terminals as shown below.
Solenoid valveBattery positiveBattery negative
Gate solenoid valve12
OK:
Operating sound (clicking) can be heard.
HINT:
When a malfunction is found in the gate solenoid valve, replace
the height control valve.
NG Replace height control valve
(See page SA±166).
OK
Page 941 of 4323
F16805
Suspension Control ECU
Wire Harness View:
S25
SLRL
F19436
Height Control Valve
Wire Harness View:
H16
321
± DIAGNOSTICSAIR SUSPENSION SYSTEM
DI±739
933 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check harness and connector (Height control valve ± Suspension control ECU,
Body ground).
PREPARATION:
Disconnect the ECU connector.
CHECK:
Check for an open or short circuit in the harness and the con-
nectors between terminal 1 of the height control valve and ter-
minal S25±4 (SLRL) of the suspension control ECU.
OK:
There is no open or short in the wire harness.
CHECK:
Check for an open circuit in the harness and the connectors be-
tween terminal 2 of the height control valve and body ground.
OK:
There is no open in the wire harness.
NG Repair or replace harness or connector.
OK
Replace suspension control ECU
(See page IN±35).
Page 942 of 4323

F19454
Suspension Control ECU H16
Leveling Solenoid Valve
(Height Control Valve)
LG±R4
BM1SLRR 313
IN13
S25
BI W±B 2LG±R
LG±R DI±740
± DIAGNOSTICSAIR SUSPENSION SYSTEM
934 Author: Date:
2005 SEQUOIA (RM1146U)
DTC C1734/34 Leveling Solenoid Valve Circuit
CIRCUIT DESCRIPTION
The suspension control ECU opens the leveling solenoid valve (height control valve) to lead the compressed
air to the height control cylinder (pneumatic cylinder) and to raise the vehicle height.
The height control valve consists of a leveling solenoid valve and a gate solenoid valve.
The leveling solenoid valve opens and closes the passage between the compressor and the height control
cylinder (pneumatic cylinder).
DTC No.DTC Detecting ConditionTrouble Area
C1734/34
Either of the following conditions is detected:
1. With the height control valve inactivated, an open signal of
the height control valve is detected for 1 sec. or more.
2. With the height control valve activated, a short signal of the
valve is detected 8 times successively.
Leveling solenoid valve (Height control valve)
Leveling solenoid valve (Height control valve) circuit
Suspension control ECU
HINT:
Once the ECU stores DTC C1734/34 in the memory, the vehicle height control is suspended until a
normal signal is input to the ECU from the height control solenoid valves. However, control is resumed
if the ignition switch is turned OFF, then ON again.
Malfunction in the leveling solenoid valve:
The height control operation is suspended, and the height control indicator lamp does not change by
operating the height control switch.
WIRING DIAGRAM
DIDDR±01
Page 943 of 4323

± DIAGNOSTICSAIR SUSPENSION SYSTEM
DI±741
935 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
If DTC C1761/61 (ECU malfunction) and/or C1774/74 (power source circuit) is displayed, perform the
inspection necessary for DTC C1761/61 (See page DI±761) and/or C1774/74 (See page DI±763) first.
(If DTC C1761/61 and the C1774/74 are output at the same time, perform the inspection necessary
for DTC C1774/74 first.)
Start the inspection from step 1 when using the hand±held tester, and start from step 2 when not using
the hand±held tester
1 Perform active test using hand±held tester.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON, and push the hand±held tester main switch ON.
(c) Select the item ºLEVEL SOL REARº in the ACTIVE TEST, and operate it with the hand±held tester.
AIR SUSPENSION:
ItemVehicle Condition / Test DetailsDiagnostic Note
LEVEL SOL REARTurn leveling solenoid valve / ON or OFFOperation sound of solenoid (clicking sound) can
be heard
CHECK:
(a) Check whether the solenoid makes sound.
(b) Check whether the height control solenoid valve has continuity (will vibrate).
OK:
The solenoid makes sound, and the height control solenoid valve has continuity (will vibrate).
RESULT:
NGA
OK (When troubleshooting according to the PROBLEM SYMPTOMS TABLE)B
OK (When troubleshooting according to the DTC chart)C
B Proceed to next circuit inspection shown in
problem symptoms table (See page DI±716).
C Replace suspension control ECU
(See page IN±35).
A
Page 944 of 4323
F19437
Connector Front View:
32 1
DI±742
± DIAGNOSTICSAIR SUSPENSION SYSTEM
936 Author: Date:
2005 SEQUOIA (RM1146U)
2 Inspect leveling solenoid valve (height control valve).
PREPARATION:
Disconnect the valve connector.
CHECK:
Measure the resistance between terminals.
OK:
Solenoid valveTester connectionResistance
Leveling solenoid valve2 ± 310 to 14 W
CHECK:
Check the operating sound of the valves when battery voltage
is applied to the terminals as shown below.
Solenoid valveBattery positiveBattery negative
Leveling solenoid valve32
OK:
Operating sound (clicking) can be heard.
HINT:
When a malfunction is found in the the leveling solenoid valve,
replace the height control valve.
NG Replace height control valve
(See page SA±166).
OK