Toyota Sequoia (2005). Manual — part 241

F19437

Height Control Valve
Connector Front View:

3 2 1

F19457

Height Control Compressor
Connector Front View:

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

DI–759

953

3

Inspect height control valve (Gate solenoid valve, Leveling solenoid valve) or
height control compressor (Exhaust solenoid valve).

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

AIR SUSPENSION:

Item

Vehicle Condition / Test Details

Diagnostic Note

LEVEL SOL REAR

Turn leveling solenoid valve / ON or OFF

Operation sound of solenoid (clicking sound) can

be heard

GATE SOL REAR

Turn gate solenoid valve / ON or OFF

Operation sound of solenoid (clicking sound) can

be heard

HINT:
The exhaust solenoid valve cannot be tested in ACTIVE TEST.
CHECK:
(a)

Check whether the solenoid makes a sound.

(b)

Check whether the height control solenoid valve has continuity (will vibrate).

OK:

The solenoid makes a sound, and the height control solenoid valve has continuity. (It will vi-
brate.)

When not using hand–held tester:
PREPARATION:
Disconnect the valve connector.
CHECK:
Check the operating sound of the valves when battery positive
voltage is applied to the terminals as shown below.

Solenoid valve

Battery positive

Battery negative

Height control valve
(Gate solenoid valve)

1

2

Height control valve
(Leveling solenoid valve)

3

2

Height control compressor
(Exhaust solenoid valve)

1

2

OK:

It make an operating sound (click).

HINT:

When a malfunction is found in the gate solenoid valve,
replace the leveling valve and the height control valve.

When a malfunction is found in the exhaust solenoid
valve, replace the height control compressor assy.

DI–760

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

954

NG

Replace height control valve assy
(See page

SA–162

).

NG

Replace height control compressor assy
(See page

SA–162

).

OK

4

Inspect height control sensor sub–assy.

CHECK:
Inspect and adjust the height control sensor sub–assy (See page

SA–156

).

NEXT

5

Reconfirm DTC.

CHECK:
Clear the DTC and repeat the procedure to re–check it (See page

DI–729

).

HINT:
If the DTC C1751/51 is still output, proceed to the next step.

NEXT

Check and repair or replace malfunctioning
parts.

(a)

Air tube is clogged (See page

SA–156

).

(b)

Compressor is faulty (See page

SA–162

).

(c)

Relief valve is faulty (See page

SA–166

).

(d)

Height control sensor sub–assy is faulty (See page

SA–156

).

(e)

Foreign material entered the height control solenoid valve (gate solenoid valve) and the exhaust sole-
noid valve.

(f)

Air leakage due to damage to the height control cylinder assy (pneumatic cylinder).

(g)

Suspension control ECU malfunctions (See page

IN–35

).

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

DI–761

955

DTC

C1761/61 ECU Malfunction

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

C1761/61

Suspension control ECU malfunction

Power source circuit

Suspension control ECU

Communication circuit

INSPECTION PROCEDURE

HINT:

If DTC C1774/74 (power source circuit) is displayed, perform the inspection necessary for DTC
C1774/74 first (See page

DI–763

).

If DTC U0122/67, U0100/65, U0132/71 and C1761/61 (ECU malfunction) are output at the same time,
perform the inspection necessary for the CAN communication system first.

The suspension control ECU, controlling the air suspension system, is activated when the ignition
switch is turned ON.
After 2 seconds, the ”MAIN RELAY” built in the ECU is activated and the system is driven by +B power
source.
Vehicle height may increase after turning the ignition switch off and unloading the vehicle/letting
people get out of the vehicle. In order to adjust the vehicle height, vehicle height control will continue
for a while from then.

DIDDY–01

F16805

S25

Wire Harness View:

BAT

B

GND

DI–762

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

956

1

Inspect suspension control ECU (ECU power source).

PREPARATION:
Disconnect the ECU connector.
CHECK:
Measure the voltage according to the value(s) in the table be-
low.
OK:

Tester connection

(Symbol)

Condition

specified condition

S25–24 (B) –

S25–22 (GND)

Always

10 to 14 V

S25–25 (BAT) –

S25–22 (GND)

Always

10 to 14 V

NG

Check power source circuit
(See page

DI–761

).

OK

Replace suspension control ECU
(See page

IN–35

).