Infiniti QX56 (Z62). Manual - part 1108

C1801 VHCL HEIGHT SENSOR

SCS-69

< DTC/CIRCUIT DIAGNOSIS >

[AIR LEVELIZER CONTROL SYSTEM]

C

D

F

G

H

I

J

K

L

M

A

B

SCS

N

O

P

DTC/CIRCUIT DIAGNOSIS

C1801 VHCL HEIGHT SENSOR

DTC Logic

INFOID:0000000006256062

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If “DTC CONFIRMATION PROCEDURE” has been previously conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.

>> GO TO 2.

2.

CHECK DTC DETECTION

 With CONSULT-III

1.

Turn ignition switch ON and wait 60 seconds or more.

2.

Perform “Self Diagnostic Results” in “E-SUS”.

Is “C1801” detected ?

YES

>> Go to 

SCS-69, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006256063

1.

CHECK APPEARANCE

Visually check for malfunction of suspension components, installing malfunction, or deformation of vehicle
height sensor.
Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repaire or replace damaged parts. 

2.

CHECK POWER SUPPLY CIRCUIT (PART 1)

1.

Disconnect vehicle height sensor connector.

2.

Turn ignition switch ON.

CAUTION:

Never start the engine.

3.

Check voltage between vehicle height sensor harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 3.

3.

CHECK POWER SUPPLY CIRCUIT (PART 2)

1.

Turn ignition switch OFF.

2.

Disconnect air levelizer control module connector.

DTC

Display itemI

Malfunction detected condition

Possible cause

C1801

VHCL HEIGHT SENSOR

Signal voltage of the vehicle height sensor remains 0.2 
V or less or 4.6 V or more continuously for 60 seconds 
during sensor voltage (4.5 – 5.5 V) output by the air lev-
elizer control module.

• Harness or connectors

(Sensor circuit is open.)

• Vehicle height sensor
• Air levelizer control module
• Rear suspension component parts

Vehicle height sensor

—

Voltage

Connector Terminal

C13

1

Ground

4.5 – 5.5 V

SCS-70

< DTC/CIRCUIT DIAGNOSIS >

[AIR LEVELIZER CONTROL SYSTEM]

C1801 VHCL HEIGHT SENSOR

3.

Check continuity between air levelizer control module harness connector and vehicle height sensor har-
ness connector.

4.

Check continuity between air levelizer control module harness connector and ground.

Is the inspection result normal?

YES

>> 1.

Check intermittent incident. Refer to 

GI-40, "Intermittent Incident"

.

2.

If inspection result is OK, replace the air levelizer control module. Refer to 

SCS-94, "Removal

and Installation"

.

NO

>> Repair or replace damaged parts.

4.

CHECK HARNESS BETWEEN AIR LEVELIZER CONTROL MODULE AND VEHICLE HEIGHT SENSOR

1.

Turn ignition switch OFF.

2.

Disconnect air levelizer control module connector.

3.

Check continuity between air levelizer control module harness connector and vehicle height sensor har-
ness connector.

4.

Check continuity between air levelizer control module harness connector and ground.

Are the inspection results normal?

YES

>> GO TO 5.

NO

>> Repair or replace damaged parts.

5.

CHECK VEHICLE HEIGHT SENSOR

Check the vehicle height sensor. Refer to 

SCS-70, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Replace the vehicle height sensor. Refer to 

SCS-98, "Removal and Installation"

.

6.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> Replace the air levelizer control module. Refer to 

SCS-94, "Removal and Installation"

.

NO

>> Repair or replace damaged parts.

Component Inspection

INFOID:0000000006256064

1.

CHECK VEHICLE HEIGHT SENSOR

Air levelizer control module

Vehicle height sensor

Continuity

Connector

Terminal

Connector

Terminal

B84

13

C13

1

Existed

Air levelizer control module

—

Continuity

Connector

Terminal

B84

13

Ground

Not existed

Air levelizer control module

Vehicle height sensor

Continuity

Connector

Terminal

Connector

Terminal

B84

5

C13

2

Existed

4

3

Air levelizer control module

—

Continuity

Connector

Terminal

B84

5

Ground

Not existed

4

C1801 VHCL HEIGHT SENSOR

SCS-71

< DTC/CIRCUIT DIAGNOSIS >

[AIR LEVELIZER CONTROL SYSTEM]

C

D

F

G

H

I

J

K

L

M

A

B

SCS

N

O

P

1.

Remove the vehicle height sensor. Refer to 

SCS-98, "Removal and Installation"

.

2.

Check resistance between vehicle height sensor connector ter-
minals.

Are the inspection results normal?

YES

>> 1.

Install the vehicle height sensor. Refer to 

SCS-94, "Removal and Installation"

.

2.

Perform “STANDARD VEHICLE HEIGHT SETTING”. Refer to 

SCS-67, "Work Procedure"

.

NO

>> Replace the vehicle height sensor. Refer to 

SCS-98, "Removal and Installation"

.

Vehicle height sensor

Condition

Resistance (Approx.)

Terminal

1

2

A position

1.9 – 3.0 k

Ω

B position

320 – 680 

Ω

1

3

Always

1.6 – 2.4 k

Ω

2

3

A position

320 – 680 

Ω

B position

1.9 – 3.0 k

Ω

JSEIA0249ZZ

SCS-72

< DTC/CIRCUIT DIAGNOSIS >

[AIR LEVELIZER CONTROL SYSTEM]

C1802 AIR SUS COMPRS RELAY

C1802 AIR SUS COMPRS RELAY

DTC Logic

INFOID:0000000006256065

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If “DTC CONFIRMATION PROCEDURE” has been previously conducted, always turn ignition switch OFF
andwait at least 10 seconds before conducting the next test.

>> GO TO 2.

2.

CHECK DTC DETECTION

 With CONSULT-III

1.

Turn ignition switch ON and wait 10 seconds or more.

2.

Select “COMPRESSOR” in “Active Test” in “E-SUS”.

3.

Touch “ON” and wait 5 seconds or more.

4.

Select “Self Diagnostic Result” in “E-SUS”.

Is “C1802” detected ?

YES

>> Go to 

SCS-72, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006256066

1.

CHECK AIR COMPRESSOR ON SIGNAL FROM AIR LEVELIZER CONTROL MODULE

 CONSULT-III

1.

Disconnect air compressor relay connector.

2.

Turn ignition switch ON.

CAUTION:

Never start the engine.

3.

Select “COMPRESSOR” in “Active Test” in “E-SUS”.

4.

Touch “ON”.

5.

While operating test item, check voltage between air compressor relay harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 2.

2.

CHECK HARNESS BETWEEN AIR LEVELIZER CONTROL MODULE AND AIR COMPRESSOR RELAY

1.

Turn ignition switch OFF.

2.

Disconnect air levelizer control module connector.

DTC

Display item

Malfunction detected condition

Possible cause

C1802

AIR SUS COMPRS RELAY

• Output voltage of the air compressor relay remains 

9 V or less continuously for 5 seconds during air 
compressor ON signal output by the air levelizer 
control module.

• Output voltage of the air compressor relay remains 

2 V or more continuously for 10 seconds during air 
compressor OFF signal output by the air levelizer 
control module.

• Harness or connector
• Air compressor relay
• Air levelizer control module

Air compressor relay

—

Voltage

Connector

Terminal

E116

2

Ground

9 – 16 V