INFINITI QX56 2010 Factory Service Manual

POWER SUPPLY AND GROUND CIRCUITSCS-19
< COMPONENT DIAGNOSIS >
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1.POWER SUPPLY CIRCUIT CHECK
1. Disconnect height sensor connector C8.
2. Turn the ignition switch ON.
3. Check voltage between the height sensor connector C8 terminal 1 and ground.
Is 5V present?
YES >> GO TO 2.
NO >> Check harness or connector for open or short. If OK, replace the suspension control unit. Refer to RSU-26, "
Removal and Installation".
2.GROUND CIRCUIT CHECK
1. Turn ignition switch OFF.
2. Check continuity between height sensor connector C8 terminal 3 and ground.
Is continuity present?
YES >> Ground circuit is OK.
NO >> Repair harness or connector.
(+) (-) Voltage
Connector Terminal
C8 1 Ground 5V
ALEIA0026GB
Connector Terminal —Continuity
C8 3Ground Yes
ALEIA0029GB
Revision: April 20092010 QX56

SCS-20
< COMPONENT DIAGNOSIS >
COMPRESSOR MOTOR RELAY
COMPRESSOR MOTOR RELAY
DescriptionINFOID:0000000005148178
Receives suspension air compressor ON signal from suspension control unit. When activated, the compressor
motor relay supplies power to the suspension air compressor.
Component Function CheckINFOID:0000000005148179
1.CHECK COMPRESSOR MOTOR RELAY OPERATION
CAUTION:
The "COMPRESSOR" active test will remain ON until it is turned off using CONSULT-III. Allowing the
compressor to run for an extended period of time may cause damage to the suspension control sys-
tem components due to excessive air pressure.
CONSULT-III
1. Turn ignition ON.
2. Select "COMPRESSOR" of AIR LEVELIZER active test items.
3. While operating test item, check that the suspension air compressor turns ON.
Does the suspension air compressor operate properly?
YES >> Compressor motor relay and suspension air compressor are operating normally.
NO >> Refer to SCS-20, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005148180
Regarding Wiring Diagram information, refer to SCS-29, "Wiring Diagram".
1.CHECK COMPRESSOR "ON" SIGNAL FROM SUSPENSION CONTROL UNIT
CONSULT-III
1. Turn ignition switch ON.
2. Disconnect compressor motor relay connector E130.
3. Select "COMPRESSOR" of AIR LEVELIZER active test items.
4. While operating test item, check voltage to compressor motor relay connector E130 terminal 2.
Is battery voltage present while operating test item?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK COMPRESSOR "ON" SIGNAL CIRCUIT ON : Compressor turns ON
OFF : Compressor turns OFF
(+)
(-)Voltage
Connector Terminal
E130 2Ground Battery voltage
ALEIA0030GB
Revision: April 20092010 QX56

COMPRESSOR MOTOR RELAYSCS-21
< COMPONENT DIAGNOSIS >
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1. Turn ignition switch OFF.
2. Disconnect suspension control unit connector B3.
3. Check continuity between suspension control unit connector B3 (A) terminal 1 and compressor motor relay connector E130 (B)
terminal 2.
4. Check continuity between suspension control unit connector B3 (A) terminal 1 and ground.
Are the continuity test results as specified?
YES >> Replace the suspension control unit. Refer to RSU-26, "Removal and Installation".
NO >> Repair harness or connector.
3.CHECK COMPRESSOR MOTOR RELAY GROUND
1. Turn ignition switch OFF.
2. Check continuity between compressor motor relay connector E130 terminal 1 and ground.
Is continuity present?
YES >> GO TO 4.
NO >> Repair harness or connector.
4.CHECK COMPRESSOR MOTOR RELAY POWER SUPPLY
1. Disconnect compressor motor relay connector E131.
2. Check voltage between compressor motor relay E131 terminal 5 and ground.
Is battery voltage present?
YES >> GO TO 5.
NO >> Inspect fuse and repair harness or connector.
5.CHECK COMPRESSOR MOTOR RELAY OUTPUT
AB Continuity
Connector Terminal Connector Terminal
B3 1E130 2Yes
A —Continuity
Connector Terminal
B3 1Ground No
ALEIA0031GB
ConnectorTerminal —Continuity
E130 1Ground Yes
ALEIA0032GB
(+)
(-)Voltage
Connector Terminal
E131 5Ground Battery voltage
ALEIA0033GB
Revision: April 20092010 QX56

SCS-22
< COMPONENT DIAGNOSIS >
COMPRESSOR MOTOR RELAY
1. Connect compressor motor relay connectors E130 and E131.
2. Disconnect suspension air compressor connector C9.
3. Turn ignition ON.
4. Select "COMPRESSOR" of AIR LEVELIZER active test items.
5. Check voltage between compressor motor relay C9 terminal 4and ground.
Is battery voltage present?
YES >> Compressor motor relay is functioning properly.
NO >> GO TO 6.
6.CHECK AIR COMPRESSOR POWER SUPPLY CIRCUIT
Check the air compressor power supply circuit. Refer to SCS-17, "
SUSPENSION AIR COMPRESSOR : Diag-
nosis Procedure".
Does the power supply circuit test OK?
YES >> Replace the compessor motor relay.
NO >> Repair harness or connector.
(+) (-)Voltage
Connector Terminal
C9 4Ground Battery voltage
ALEIA0034GB
Revision: April 20092010 QX56

HEIGHT SENSOR SIGNAL CIRCUITSCS-23
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HEIGHT SENSOR SIGNAL CIRCUIT
DescriptionINFOID:0000000005148181
Supplies vehicle height input to the suspension control unit.
Component Function CheckINFOID:0000000005148182
1.CHECK HEIGHT SENSOR OPERATION
CONSULT-III
1. Select "HEIGT SEN" of AIR L EVELIZER data monitor test item.
2. While monitoring test item, add or take away weight from the rear of the vehicle. Check that the voltage value changes with vehicle height.
Is the HEIGHT SEN data monitor responding normally?
YES >> Height sensor is operating normally.
NO >> Refer to SCS-23, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005148183
Regarding Wiring Diagram information, refer to SCS-29, "Wiring Diagram".
1.CHECK HEIGHT SENSOR POWER AND GROUND SUPPLY
Check height sensor power and ground supply. Refer to SCS-18, "
HEIGHT SENSOR : Diagnosis Procedure".
Are the inspection results normal?
YES >> GO TO 2.
NO >> Repair harness or connector.
2.CHECK HEIGHT SENSOR SIGNAL CIRCUIT
1. Disconnect suspension control unit connector B3 and height sensor connector C8.
2. Check continuity between suspension control unit connector B3
(A) terminal 3 and height sensor connector C8 (B) terminal 2.
3. Check continuity between display unit harness connector B3 (A) terminal 3 and ground.
Are the continuity results as specified?
YES >> Replace the height sensor. Refer to RSU-27, "Removal and Installation".
NO >> Repair harness or connector. HEIGHT SEN : Voltage changes with vehicle height
AB
Continuity
Connector Terminal Connector Terminal
B33C 82 Y es
A —Contin u it y
Connector Terminal
B3 3Ground No
ALEIA0035GB
Revision: April 20092010 QX56

SCS-24
< COMPONENT DIAGNOSIS >
EXHAUST VALVE SOLENOID CIRCUIT
EXHAUST VALVE SOLENOID CIRCUIT
DescriptionINFOID:0000000005148184
Receives exhaust valve solenoid signal from suspension control unit. When activated, the exhaust valve sole-
noid releases air pressure from the suspension control system.
Component Function CheckINFOID:0000000005148185
1.CHECK EXHAUST SOLENOID OPERATION
CAUTION:
While operating this active test, the suspension control system will vent air pressure and the vehicle
ride height will lower. Ensure th e area around the vehicle is free fr om obstructions before beginning
test.
CONSULT-III
1. Ensure the suspension control system has air pressure and is not drooping in the rear.
2. Select "EXHAUST SOLENOID" of AIR LEVELIZER active test items.
3. While operating test item, check that the exhaust valve solenoid opens to vent air from the system. The vehicle should lower when the exhaust valve solenoid is activated.
Does the system vent properly?
YES >> Exhaust valve solenoid is operating normally.
NO >> Refer to SCS-24, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005148186
Regarding Wiring Diagram information, refer to SCS-29, "Wiring Diagram".
1.CHECK EXHAUST VALVE SOLENOID SIGNAL
CONSULT-III
1. Connect suspension control unit connector B3.
2. Turn ignition switch ON.
3. Select "EXHAUST SOLENOID" of AIR LEVELIZER active test
items.
4. While test item is operating, check signal between suspension
air compressor connector C9 terminal 2 and ground.
Is battery voltage present?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK CONTINUITY OF EXHA UST VALVE SOLENOID CIRCUIT
ON : Air vents and vehicle ride height lowers
OFF : No air vents and vehicle ride height remains constant
(+)
(-)Voltage
Connector Terminal
C9 2Ground Battery voltage
ALEIA0036GB
Revision: April 20092010 QX56

EXHAUST VALVE SOLENOID CIRCUITSCS-25
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1. Turn ignition switch OFF.
2. Disconnect suspension control unit connector B3 and suspen- sion air compressor connector C9.
3. Check continuity between suspension control unit connector B3 (A) terminal 9 and suspension air compressor connector C9 (B)
terminal 2.
4. Check continuity between suspension control unit connector B3 (A) terminal 9 and ground.
Are the continuity test results as specified?
YES >> Replace the suspension control unit. Refer to RSU-26, "Removal and Installation".
NO >> Repair harness or connector.
3.CHECK SUSPENSION AIR COMPRESSOR GROUND
1. Turn ignition switch OFF.
2. Check continuity between suspension air compressor connector C9 terminals 1 and 3 and ground.
Is continuity present?
YES >> Replace the suspension air compressor. Refer to RSU-
24, "Removal and Installation".
NO >> Repair harness or connector.
AB Continuity
Connector Terminal Connector Terminal
B39C 92 Y es
A —Contin u it y
Connector Terminal
B3 9Ground No
ALEIA0037GB
ConnectorTerminal —Continuity
C9 1
Ground Yes
3
ALEIA0038GB
Revision: April 20092010 QX56

SCS-26
< COMPONENT DIAGNOSIS >
CK SUSP WARNING INDICATOR CONTROL CIRCUIT
CK SUSP WARNING INDICATOR CONTROL CIRCUIT
DescriptionINFOID:0000000005148187
The CK SUSP warning lamp is controlled by a ground signal provided to the combination meter by the sus-
pension control unit.
Component Function CheckINFOID:0000000005148188
1.CHECK WARNING LAMP OPERATION
CONSULT-III
1. Turn ignition ON.
2. Select "WARNING LAMP" of AI R LEVELIZER active test items.
3. While operating test item, check that the warning lamp activates.
Does the warning lamp operate properly?
YES >> Warning lamp is operating normally.
NO >> Refer to SCS-26, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005148189
Regarding Wiring Diagram information, refer to SCS-29, "Wiring Diagram".
1.PERFORM SUSPENSION CONTROL SYSTEM SELF-DIAGNOSIS
CONSULT-III
1. Turn ignition ON.
2. Perform SELF DIAGNOSIS functi on of AIR LEVELIZER system.
Are any DTC's present?
YES >> Refer to SCS-34, "DTC Index".
NO >> • If warning lamp is always ON, GO TO 2. • If warning lamp is always OFF, GO TO 3
2.CHECK SUSPENSION CONTROL UNI T WARNING LAMP CONTROL
1. Turn ignition OFF.
2. Disconnect the suspension control unit connector B3.
3. Turn ignition ON.
Does the CK SUSP warning lamp turn ON?
YES >> GO TO 3.
NO >> Replace the suspension control unit. Refer to RSU-26, "
Removal and Installation".
3.CHECK CONTINUITY OF WARNING LAMP CONTROL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect suspension control unit connector B3 and combina- tion meter connector M24.
3. Check continuity between suspension control unit connector B3 (A) terminal 10 and combination meter connector M24 (B) termi-
nal 15.ON : Warning lamp turns ON
OFF : Warning lamp turns OFF
AB
Continuity
Connector Terminal Connector Terminal
B3 10 M24 15 Yes
ALLIA0693GB
Revision: April 20092010 QX56

CK SUSP WARNING INDICATOR CONTROL CIRCUITSCS-27
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4. Check continuity between suspension control unit connector B3 (A) terminal 10 and ground.
Are the continuity test results as specified?
YES >> Replace the combination meter. Refer to MWI-100, "Removal and Installation".
NO >> Repair harness or connector.
A —Contin u it y
Connector Terminal
B3 10Ground No
Revision: April 20092010 QX56

SCS-28
< ECU DIAGNOSIS >
SUSPENSION CONTROL UNIT
ECU DIAGNOSIS
SUSPENSION CONTROL UNIT
Reference ValueINFOID:0000000005148190
TERMINAL LAYOUT
PHYSICAL VALUES
AWLIA1640ZZ
Terminal
(Wire color) Description
ConditionReference value
(Approx.)
+ – Signal nameInput/
Output
1
(V) Ground Compressor relay output Output Ignition
switch ON Air levelizer raising vehicle
ride height
Battery voltage
3
(W) Ground Height sensor input
InputIgnition
switch
ON —0
.2 V - 4 .8 V
5
(R) Ground VREF output (height sen-
sor)
OutputIgnition
switch ON —5
V
6
(G/R) Ground IGN power supply
InputIgnition
switch ON or
START —
Battery voltage
7
(W/L) Ground BAT power supply
InputIgnition
switch OFF —
Battery voltage
8
(G/W) Ground Diagnostic K-line Input/
Output ——
—
9
(SB) Ground Exhaust valve output Output Ignition
switch ON Air levelizer lowering vehi-
cle ride height (venting)
Battery voltage
10
(BR) Ground Warning lamp output Output Ignition
switch
ON Warning lamp ON
0V
Warning lamp OFF Battery voltage
14
(L) Ground Height sensor ground Output Ignition
switch ON —
Less than 0.2V
15
(BR/W) Ground Generator input
InputIgnition
switch ON Charge light ON
0V
Charge light OFF Battery voltage
16
(B) Ground
Suspension control unit
ground InputIgnition
switch
ON —
Less than 0.2V
Revision: April 20092010 QX56