Toyota Sequoia (2005). Manual - part 245

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

DI–775

969

INSPECTION PROCEDURE

HINT:
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

Read value of the hand–held tester.

PREPARATION:
(a)

Connect the hand–held tester to the DLC3.

(b)

Turn the ignition switch ON, and turn the hand–held tester main switch ON.

(c)

Select the item ”HEIGHT SW DOWN” or ”HEIGHT SW UP” in the DATA LIST, and read its value dis-
played on the hand–held tester.

AIR SUSPENSION:

Item

Measurement Item / Range (Dis-

play)

Normal Condition

Diagnostic Note

HEIGHT SW DOWN

Height control switch (DOWN) /

ON or OFF

ON: Height control switch

”DOWN” button is pressed

OFF: –

–

HEIGHT SW UP

Height control switch (UP) / ON or

OFF

ON: Height control switch ”UP”

button is pressed

OFF: –

–

CHECK:
Check that the value displayed on the hand–held tester changes by pressing the height control switch ”UP”
or ”DOWN”.
OK:

Height control switch value changes.

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

F19433

3

UP Button

DOWN Button

Height Control 
Switch

1 2

4 5

DI–776

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

970

2

Inspect height control switch.

PREPARATION:
Remove the height control switch connector.
CHECK:
Check continuity between each terminal of the height control
switch when the height control switch ”UP” or ”DOWN” button
is pressed.
OK:

Tester connection

Switch condition

Specification

”UP” button

2 – 3

Continuity

”DOWN” button

2 – 3

No continuity

”UP” button

2 – 4

No continuity

”DOWN” button

2 – 4

Continuity

NG

Replace height control switch.

OK

F16805

Suspension Control ECU
Wire Harness View:

S25

UPSW

DNSW

F19462

Height Control Switch Wire Harness
Side Connector Front View:

H12

E

LWS

HSW

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

DI–777

971

3

Check harness and connector (Height control switch – Suspension control ECU,
Body ground).

PREPARATION:
Disconnect the ECU connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Tester connection

(Symbol)

Condition

Specified condition

S25–13 (UPSW) – 

H12–3 (HSW)

Always

Below 1 

Ω

S25–32 (DNSW) –

H12–4 (LWS)

Always

Below 1 

Ω

H12–2 (E) – Body ground

Always

Below 1 

Ω

S25–13 (UPSW) –

Body ground

Always

10 k

Ω

 or higher

S25–32 (DNSW) –

Body ground

Always

10 k

Ω

 or higher

NG

Repair or replace harness or connector.

OK

Replace suspension control ECU
(See page 

IN–35

).

F19449

H17
Height Control Mode
Select Switch

Suspension Control
ECU

W–B

IM

4

BR–B

3

12

S25 TD

DI–778

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

972

DTC

C1788/88 Height Control Mode Select Switch Circuit

(Test Diagnosis)

CIRCUIT DESCRIPTION

Height control can be operated or suspended by pressing the height control mode select switch.
By pressing the switch once, height control can be suspended.
By pressing the switch one more time, height control can be operated.
HINT:
The DTC is output only when the sensor signal check is done.

DTC No.

DTC Detecting Condition

Trouble Area

C1788/88

Height control mode select switch signal does not change.

Height control mode select switch

Height control mode select switch circuit

Suspension control ECU

WIRING DIAGRAM

DIDEF–01