INFINITI QX4 2005 Factory Service Manual

RSU-16
TROUBLE DIAGNOSIS
Revision: October 20052005 QX56
Display Item List
X: Applicable
–: Not applicable
ACTIVE TEST
CAUTION:

Do not perform active test while driving.
Operation Procedure
1. Connect the CONSULT-II and CONSULT-II CONVERTER to the data link connector and start the engine.
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II CONVERTER, malfunctions might be
detected in self-diagnosis depending on control unit which carries out CAN communication.
2. Touch "START (NISSAN BASED VHCL)" on the display screen.
3. Touch "AIR LEVELIZER".
If "AIR LEVELIZER" is not indicated, go to GI-39, "
CONSULT-II Data Link Connector (DLC) Circuit" .
4. Touch "ACTIVE TEST".
5. The "SELECT TEST ITEM" screen is displayed.
6. Touch necessary test item.
7. With the "MAIN SIGNALS" display highlighted, touch "START".
8. The active test screen will be displayed.
Display Item List
CAUTION:
The "COMPRESSOR" active test will remain ON until it is turned off using CONSULT-II. Allowing the
compressor to run for an extended period of time may cause damage to air suspension system com-
ponents due to excessive pressure in the air suspension system.
NOTE:

"TEST IS STOPPED" is displayed approximately 10 seconds after operation starts for all active test items
except "COMPRESSOR".

After "TEST IS STOPPED" is displayed, to perform test again, repeat Step 6.
Te s t I t e mData monitor item selection
ALL
SIGNALSSELECTION
FROM MENU
HEIGT SENXX
HEIGT CALCXX
SEN FIX TIMEXX
HEIGT INI VALXX
COMPRESSOR X X
EXH SOLENOID X X
ACG LXX
Test Item Description
COMPRESSOROFF/ON
EXHAUST SOLENOIDOFF/ON
WARNING LAMPOFF/ON

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
RSU-17
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RSU
Revision: October 20052005 QX56
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMSPFP:00000
Height Sensor System InspectionEES001HA
INSPECTION PROCEDURE
1. SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
Is the above displayed in the self-diagnosis display items?
YES >> GO TO 3.
NO >> GO TO 2.
2. DATA MONITOR CHECK
Conduct data monitor of "HEIGT SEN" to check if the status is normal.
OK or NG
OK >> Inspection End.
NG >> GO TO 3.
3. CONNECTOR INSPECTION
1. Turn ignition switch OFF.
2. Disconnect suspension control unit connector B3 and height sensor C8.
3. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace as necessary.
Self-diagnosis results
C1801
C1806
C1807
HEIGT SEN 0.2V - 4.8V

RSU-18
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: October 20052005 QX56
4. CHECK HEIGHT SENSOR POWER AND GROUND
1. Reconnect the suspension control unit connector.
2. Turn the ignition switch ON.
3. Check voltage between height sensor connector C8 terminal 1
(R) and ground.
4. Turn ignition switch OFF.
5. Check resistance between height sensor connector C8 terminal
3 (L) and ground.
OK or NG
OK >> GO TO 5.
NG >> Repair the circuit.
5. CHECK HEIGHT SENSOR SIGNAL CIRCUIT
1. Disconnect the suspension control unit.
2. Check resistance between height sensor connector C8 terminal
2 (W) and suspension control unit connector B3 terminal 3 (W).
3. Check resistance between height sensor connector C8 terminal
2 (W) and ground.
OK or NG
OK >> Replace the height sensor. Refer to RSU-44, "HEIGHT
SENSOR" .
NG >> Repair the circuit.Voltage : Approx. 5V
WEIA0084E
Continuity should exist.
WEIA0085E
Continuity should exist.
WEIA0086E
Continuity should not exist.
WEIA0087E

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
RSU-19
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RSU
Revision: October 20052005 QX56
Exhaust Valve Solenoid System InspectionEES001HB
INSPECTION PROCEDURE
1. SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
Is the above displayed in the self-diagnosis display items?
YES >> If code C1803 was retrieved during self-diagnosis, GO TO 3. If code C1805 was retrieved during
self-diagnosis, GO TO 2.
NO >> Inspection End.
2. CHECK SYSTEM OPERATION
1. Load vehicle to standard laden condition (with driver, front passenger, 2 passengers in second row seats
and no cargo).
2. Conduct active test of "COMPRESSOR" to raise vehicle ride height to +20mm.
CAUTION:
The "COMPRESSOR" active test will remain ON until it is turned off using CONSULT-II. Allowing
the compressor to run for an extended period of time may cause damage to air suspension sys-
tem components due to excessive pressure in the air suspension system.
3. Return the rear load leveling air suspension system to normal operating mode.
4. Check self-diagnostic results.
Is code C1805 displayed again?
YES >> GO TO 3.
NO >> Inspection End.
3. CONNECTOR INSPECTION
1. Disconnect suspension control unit connector B3 and suspension air compressor C9.
2. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> If code C1805 was retrieved during self-diagnosis, GO TO 4. If code C1803 was retrieved during
self-diagnosis, GO TO 6.
NG >> Repair or replace as necessary.
4. AIR HOSE INSPECTION
Inspect for pinched or damaged air hoses between the suspension air reservoir and each load leveling rear air
suspension shock absorber.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace as necessary.
Self-diagnosis results
C1803
C1805

RSU-20
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: October 20052005 QX56
5. EXHAUST VALVE SOLENOID INSPECTION
Apply 12V to suspension air compressor C9 terminal 2 and body
ground to suspension air compressor C9 terminal 1.
OK or NG
OK >> GO TO 6.
NG >> Replace the suspension air compressor. Refer to RSU-
42, "REAR LOAD LEVELING AIR SUSPENSION COM-
PRESSOR ASSEMBLY" .
6. CHECK EXHAUST VALVE SOLENOID POWER AND GROUND
1. Reconnect the suspension control unit connector.
2. Turn the ignition switch ON.
3. Check voltage between suspension air compressor connector
C9 terminal 2 (SB) and ground.
4. Check resistance between suspension air compressor connec-
tor C9 terminal 1 (B) and ground.
OK or NG
OK >> Replace the suspension control unit. Refer to RSU-46,
"CONTROL UNIT" .
NG >> Repair the circuit.
Compressor Motor, Compressor Motor Relay and Circuit InspectionEES001HC
INSPECTION PROCEDURE
1. SELF-DIAGNOSIS RESULT CHECK
Check self-diagnosis results.
Is the above displayed in the self-diagnosis display items?
YES >> If code C1802 was retrieved during self-diagnosis, GO TO 3. If code C1804 or C1808 was
retrieved during self-diagnosis, GO TO 2.
NO >> Inspection End.System air pressure should vent.
WEIA0063E
Voltage : Approx. 12V
WEIA0088E
Continuity should exist.
WEIA0089E
Self-diagnosis results
C1802
C1804
C1808

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
RSU-21
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RSU
Revision: October 20052005 QX56
2. CHECK SYSTEM OPERATION
1. Load vehicle to standard laden condition (with driver, front passenger, 2 passengers in second row seats
and no cargo).
2. Conduct active test of "EXHAUST SOLENOID" to lower vehicle ride height to -20mm.
3. Return the rear load leveling air suspension system to normal operating mode.
4. Check self-diagnostic results.
Is code C1804 or C1808 displayed again?
YES >> GO TO 3.
NO >> Inspection End.
3. CONNECTOR INSPECTION
1. Disconnect suspension control unit connector B3 and suspension air compressor C9.
2. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> If code C1804 or C1808 was retrieved during self-diagnosis, GO TO 4. If code C1802 was
retrieved during self-diagnosis, GO TO 6.
NG >> Repair or replace as necessary.
4. AIR HOSE INSPECTION
Inspect for pinched or damaged air hoses between the suspension air reservoir and each load leveling rear air
suspension shock absorber.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace as necessary.
5. SUSPENSION AIR COMPRESSOR INSPECTION
Apply 12V to suspension air compressor C9 terminal 2 and body
ground to suspension air compressor C9 terminal 1.
OK or NG
OK >> GO TO 6.
NG >> Replace the suspension air compressor. Refer to RSU-
42, "REAR LOAD LEVELING AIR SUSPENSION COM-
PRESSOR ASSEMBLY" . System air pressure should vent.
WEIA0066E

RSU-22
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: October 20052005 QX56
6. CHECK SUSPENSION AIR COMPRESSOR POWER AND GROUND
1. Turn the ignition switch ON.
2. Check voltage between suspension air compressor connector
C9 terminal 2 (SB) and ground.
3. Check resistance between suspension air compressor connec-
tor C9 terminal 1 (B) and ground.
OK or NG
OK >> Replace the suspension control unit. Refer to RSU-46,
"CONTROL UNIT" .
NG >> Repair the circuit.Voltage : Approx. 12V
WEIA0090E
Continuity should exist.
WEIA0091E

TROUBLE DIAGNOSES FOR SYMPTOMS
RSU-23
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RSU
Revision: October 20052005 QX56
TROUBLE DIAGNOSES FOR SYMPTOMSPFP:99999
Load Leveling Rear Air Suspension System Does Not OperateEES001HD
1. CHECK WARNING LAMP ACTIVATION
Make sure warning lamp remains off while driving.
OK or NG
OK >> GO TO 2.
NG >> Carry out self-diagnosis. Refer to RSU-14, "
SELF-DIAGNOSIS" .
2. CHECK FUSES
Check that the following fuses are not blown.
OK or NG
OK >> GO TO 3.
NG >> If fuse is blown, be sure to eliminate cause of blown fuse before installing new fuse. Refer to PG-
4, "POWER SUPPLY ROUTING CIRCUIT" .
3. CHECK SUSPENSION CONTROL UNIT POWER AND GROUND
1. Turn the ignition switch ON.
2. Check voltage between suspension control unit connector B3
terminal 6 (G/R) and ground and between suspension control
unit connector B3 terminal 7 (W/L) and ground.
3. Check resistance between suspension control unit connector B3
terminal 16 (B) and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair the circuit.
Unit Terminals Signal name Fuse or Fusible Link
Suspension control unit6 Ignition switch ON or START 12 (10A)
7
Battery power29 (10A)
Compressor motor relay 5 g (30A)
Combination meter24 Ignition switch ON or START 14 (10A)
8 Battery power 19 (10A)
Voltage : Approx. 12V
WEIA0069E
Continuity should exist.
WEIA0070E

RSU-24
TROUBLE DIAGNOSES FOR SYMPTOMS
Revision: October 20052005 QX56
4. CHECK GENERATOR SIGNAL INPUT
1. Start the engine.
2. Check voltage between suspension control unit connector B3
terminal 15 (BR/W) and ground.
OK or NG
OK >> Replace the suspension control unit. Refer to RSU-46,
"CONTROL UNIT" .
NG >> Repair the circuit.
CK SUSP Indicator Lamp Stays On When Ignition Switch Is Turned OnEES001HE
1. CARRY OUT SELF-DIAGNOSIS
Carry out self-diagnosis. Refer to RSU-14, "
SELF-DIAGNOSIS" .
Are malfunctions detected in self-diagnosis?
YES >> Refer to RSU-16, "Display Item List" .
NO >> Refer to DI-30, "
WARNING LAMPS" . Voltage : Approx. 12V
WEIA0071E

REAR SUSPENSION ASSEMBLY
RSU-25
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RSU
Revision: October 20052005 QX56
REAR SUSPENSION ASSEMBLYPFP:55020
ComponentsEES001HF
Rear Suspension
WEIA0092E