Toyota Sequoia (2005). Manual - part 235

F16806

High (45

°)

Low (–45

°)

Normal (0

°)

Connector Front View:

SHG

SHRL

SHB

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

DI–735

929

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:

Position

Voltage

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

).

F19442

Suspension Control ECU

H16 
Gate Solenoid Valve
(Height Control Valve)

W–L

8

BM1

SLRL

1

14

IN1

4

S25

BI

W–B

2

W–L

W–L

DI–736

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

930

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 Condition

Trouble 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

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

DI–737

931

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 ”GATE SOL REAR” in the ACTIVE TEST, and operate it with the hand–held tester.

AIR SUSPENSION:

Item

Vehicle Condition / Test Details

Diagnostic Note

GATE SOL REAR

Turn gate solenoid valve / ON or OFF

Operation 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:

NG

A

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

F19437

Connector Front View:

3 2 1

DI–738

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

932

2

Inspect gate solenoid valve (height control valve).

PREPARATION:
Disconnect the valve connector.
CHECK:
Measure the resistance between terminals.
OK:

Solenoid valve

Tester connection

Resistance

Gate solenoid valve

1 – 2

17.5 to 21.5 

Ω

CHECK:
Check the operating sound of the valves when battery voltage
is applied to the terminals as shown below.

Solenoid valve

Battery positive

Battery negative

Gate solenoid valve

1

2

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