Toyota Sequoia (2005). Manual - part 230

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

DI–715

909

Test mode (input signal check) table:

Check Item

Operation (A)

Operation (B)

Stop light switch signal

OFF (Brake pedal not depressed)

ON (Brake pedal depressed)

Door courtesy light switch signal

ON (Each door opened)

OFF (All doors closed)

Height control switch signal

–

Press the height control switch ”UP” first and

then press ”DOWN”

Height control mode select switch signal

OFF (Height control mode select switch not

pushed in)

ON to OFF (Height control mode select switch

pushed in and released)

HINT:
In step (6), all signals can be checked together.

(7)

Read the test mode DTCs by following the prompts
on the tester screen.

HINT:
Refer to the hand–held tester operator’s manual for further de-
tails.

(8)

Check the malfunction using the code table below.

DTC of air suspension system test mode (input signal check) function:
If a trouble code is displayed during the test mode DTC check, check the circuit listed for that code. For details
of each code, refer to ”See page” under the respective DTC No. in the chart.

DTC No.

(See Page)

Detection Item

Trouble Area

C1782/82

(

DI–767

)

Stop light switch circuit malfunction

Stop light switch assy

Stop light switch circuit

Suspension control ECU

C1783/83

(

DI–770

)

Door courtesy switch circuit malfunction

Door courtesy light switch assy

W/ Motor back door assy

Door courtesy light switch circuit

Body ECU

Back door ECU

Suspension control ECU

C1786/86

(

DI–774

)

Height control switch circuit malfunction

Height control switch

Height control switch circuit

Suspension control ECU

C1788/88

(

DI–778

)

Height control mode select switch circuit malfunction

Height control mode select switch

Height control mode select switch circuit

Suspension control ECU

(9)

After completing the test mode, disconnect the tes-
ter and turn the ignition switch off.

DIDCZ–01

DI–716

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

910

PROBLEM SYMPTOMS TABLE

HINT:

If a normal system code is displayed during the DTC check but the problem still occurs, check the cir-
cuits for each problem symptom in the order given in the table below and proceed to the relevant trou-
bleshooting page.

Inspect the fuse before inspecting the suspected areas as shown in the chart below.

Inspect each malfunction circuit in numerical order for the corresponding symptom.

If the malfunction still exists even after checking and confirming that all the circuits are normal, replace
the suspension control ECU.

Symptom

Suspected Area

See page

Vehicle height control function does not operate.

If the compressor remains on for an excessive period of

time or turns on and off repeatedly, the system control will

be halted for up to 70 minutes, after which the system will

return to normal operation.

1. Air tube is seized

2. Power source circuit

3. IG signal circuit

4. Crankshaft position sensor circuit

5. Height control mode select switch circuit

6. Height control switch circuit

7. Height control sensor circuit

8. Leveling solenoid valve circuit

9. Gate solenoid valve circuit

10.Exhaust solenoid valve circuit

11.AIR SUS relay circuit

12.Height control compressor circuit

13.Suspension control ECU

–

DI–761

DI–793

DI–210

DI–778

DI–774

DI–731

DI–740

DI–736

DI–744

DI–747

DI–752

IN–35

Illuminated position of height control indicator lamp does not

change by the height control switch operation.

1. Power source circuit

2. Crankshaft position sensor circuit

3. Height control mode select switch circuit

4. Height control switch circuit

5. Height control sensor circuit

6. Leveling solenoid valve circuit

7. Gate solenoid valve circuit

8. Exhaust solenoid valve circuit

9. AIR SUS relay circuit

10.Height control compressor circuit

11.Speed sensor circuit

12.CAN communication circuit

13.Suspension control ECU

DI–763

DI–761

DI–793

DI–210

DI–778

DI–774

DI–731

DI–740

DI–736

DI–744

DI–783

DI–1065

IN–35

Hunting of vehicle height occurs.

1. Air leakage

 

(Height control cylinder assy rear)

2. Height control sensor circuit

3. Suspension control ECU

SA–156

DI–731

IN–35

Vehicle height control operates, but vehicle height is uneven.

1. Air leakage

2. Clogging of the air tube

3. Height control sensor link sub–assy

4. Height control sensor circuit

5. Gate solenoid valve circuit

6. Suspension control ECU

SA–156

–

SA–156

DI–731

DI–736

IN–35

Vehicle height control operates, but vehicle height is high or

low (Vehicle height in NORMAL mode differs from the standard

value).

1. Height control sensor link sub–assy

2. Height control sensor circuit

3. Suspension control ECU

SA–156

DI–731

IN–35

When vehicle height control is adjusted, it stops at extremely high

or low position.

1. Height control sensor circuit

2. Height control sensor link sub–assy

3. Suspension control ECU

DI–731

SA–156

IN–35

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

DI–717

911

Height control manual indicator lamp condition is abnormal.

1. Power source circuit

2. Height control mode select switch circuit

3. Height control manual indicator lamp circuit

4. Suspension control ECU

DI–763

DI–778

DI–789

IN–35

Height control indicator lamp condition is abnormal.

1. Power source circuit

2. Height control indicator lamp circuit

3. Suspension control ECU

DI–763

DI–785

IN–35

DTC check cannot be completed.

1. Power source circuit

2. CAN communication system

3. Height control manual indicator lamp circuit

4. Suspension control ECU

5. ECM

DI–763

DI–782

DI–789

IN–35

IN–35

Input signal check (test mode) cannot be completed.

1. Power source circuit

2. CAN communication system

3. Suspension control ECU

4. Translate ECU

DI–763

DI–783

IN–35

IN–35

Vehicle height is extremely low when vehicle is parked.

Although, especially in a cold district, the vehicle height
may become lower due to a drop in air temperature in the
height control cylinder assy, but this is not abnormal.
1. Air leakage

2. Height control cylinder assy

3. Height control sensor link sub–assy

4. Leveling solenoid valve circuit

5. Exhaust valve circuit

SA–156

–

SA–156

DI–740

DI–744

Compressor motor continues to operate.

Due to the air tube freezing, vehicle height may not rise.
1. Air leakage

2. Air tube clogged

3. Height control cylinder assy

4. Height control sensor link sub–assy

5. Height control sensor circuit

6. Leveling solenoid valve circuit

7. Exhaust valve circuit

8. AIR SUS relay circuit

9. Height control compressor circuit

10.Suspension control ECU

SA–156

–

–

SA–156

DI–731

DI–740

DI–744

DI–747

DI–752

IN–35

DIDD3–01

F16803

S25

DI–718

–

DIAGNOSTICS

AIR SUSPENSION SYSTEM

912

TERMINALS OF ECU

Symbols (Terminal No.)

Wiring Color

Terminal 

Description

Condition

Specified Condition

SLEX (S25–1) – 

L R

W B

Exhaust Sole-

id V l

Si

IG switch ON 

→

E

i

idli

b tt

f h i ht

t l

it h i

h d

Below 1.0 V 

→

SLEX (S25 1)   

GND (S25–22)

L–R – W–B

noid Valve Sig-

nal

Engine idling, button of height control switch is pushed

from ”UP” to ”DOWN”

Below 1.0 V 

→

9 V or more

SLRR (S25–3) – 

LG R

W B

Leveling Sole-

id V l

Si

IG switch ON 

→

E

i

idli

b tt

f h i ht

t l

it h i

h d

Below 1.0 V 

→

SLRR (S25 3)   

GND (S25–22)

LG–R – W–B

noid Valve Sig-

nal

Engine idling, button of height control switch is pushed

from ”DOWN” to ”UP”

Below 1.0 V 

→

9 V or more

SLRL (S25–4) – 

W L

W B

Gate Solenoid

IG switch ON 

→

E

i

idli

b tt

f h i ht

t l

it h i

h d

Below 1.0 V 

→

SLRL (S25 4)   

GND (S25–22)

W–L – W–B

Gate Solenoid

Valve Signal

Engine idling, button of height control switch is pushed

from ”DOWN” to ”UP”

Below 1.0 V 

→

9 V or more

RC (S25–5) – 

G Y

W B

AIR SUS Relay

IG switch ON 

→

E

i

idli

b tt

f h i ht

t l

it h i

h d

Below 1.0 V 

→

RC (S25 5)   

GND (S25–22)

G–Y – W–B

AIR SUS Relay

Signal

Engine idling, button of height control switch is pushed

from ”N” to ”UP”

Below 1.0 V 

→

9 V or more

HI (S25–8) – 

GR R

W B

Height Control

I di

t

”HI”

Engine idling, vehicle height is ”NORMAL” 

→

P

i

th ”UP” b tt

f th

t l

it h t

10 V or more 

→

HI (S25 8)   

GND (S25–22)

GR–R – W–B

Indicator ”HI”

Signal

Pressing the ”UP” button of the control switch turns on

the ”HI” indicator lamp (*1)

10 V or more 

→

Below 5 V

NR (S25–9) – 

B L

W B

Height Control

I di

t

”N”

Engine idling, vehicle height is ”NORMAL” 

→

P

i

th ”UP” b tt

f th

t l

it h t

Below 5 V 

→

NR (S25 9)   

GND (S25–22)

B–L – W–B

Indicator ”N”

Signal

Pressing the ”UP” button of the control switch turns on

the ”HI” indicator lamp (*1)

Below 5 V 

→

10 V or more

IG (S25–10) – 

GND (S25–22)

B–R – W–B

Ignition Switch

IG switch ON

10 to 14 V

VN (S25–11) – 

LG

W B

Height Control

M

l I di

IG switch ON, height control manual indicator lamp ON

→

 Pressing and releasing the height control mode select

Below 5 V 

→

VN (S25 11)   

GND (S25–22)

LG – W–B

Manual Indica-

tor Lamp Signal

→

 Pressing and releasing the height control mode select

switch turns off the height control manual indicator lamp

(*1)

Below 5 V 

→

10 V or more

TD (S25–12) – 

BR B

W B

Height Control

M d S l

t

IG switch ON, height control mode select switch pushed

i

Below 1.5 V 

→

TD (S25 12)   

GND (S25–22)

BR–B – W–B

Mode Select

Switch

in

 

→

 Height control select switch released

Below 1.5 V 

→

10 to 14 V

UPSW (S25–13) – 

L B

W B

Height Control

S it h ”UP”

IG switch ON, ”UP” button of height control switch

h d i

Below 1.5 V 

→

UPSW (S25 13)   

GND (S25–22)

L–B – W–B

Switch ”UP”

Signal

pushed in 

→

”UP” button of height control switch released

Below 1.5 V 

→

10 to 14 V

SBL (S25–15) – 

SGL (S25–19)

G–O – L–R

Height Control

Sensor Power

Source

IG switch ON

4.5 to 5.5 V

SHRL (S25–17) – 

GR L

L R

Height Control

S

I

t

IG switch ON 

→

E

i

idli

hi l h i ht i

h

d f

”HIGH” t

0.5 to 4.5 V 

→

SHRL (S25 17)   

SGL (S25–19)

GR–L – L–R

Sensor Input

Signal

Engine idling, vehicle height is changed from ”HIGH” to 

”NORMAL” by pressing the height control switch

0.5 to 4.5 V 

→

Approx. 2.5 V

SGL (S25–19) – 

GND (S25–22)

L–R – W–B

Height Control

Sensor Ground

Always

Below 1.0 V