2004 INFINITI QX56 suspension

RSU-18
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: August 20072004 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. Check resistance between height sensor connector C8 terminal
2 (W) and suspension control unit connector B3 terminal 3 (W).
2. Disconnect suspension control unit connector.
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.
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Continuity should exist.
WEIA0086E
Continuity should not exist.
WEIA0087E

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
RSU-19
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Revision: August 20072004 QX56
Exhaust Valve Solenoid System InspectionEES0011B
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. Turn ignition switch OFF.
2. Disconnect suspension control unit connector B3 and suspension air compressor C9.
3. 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: August 20072004 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. Turn ignition switch OFF.
5. 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 InspectionEES0011C
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
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Revision: August 20072004 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. Turn ignition switch OFF.
2. Disconnect suspension control unit connector B3 and suspension air compressor C9.
3. 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: August 20072004 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. Turn ignition switch OFF.
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.Voltage : Approx. 12V
WEIA0090E
Continuity should exist.
WEIA0091E

TROUBLE DIAGNOSES FOR SYMPTOMS
RSU-23
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Revision: August 20072004 QX56
TROUBLE DIAGNOSES FOR SYMPTOMSPFP:99999
Load Leveling Rear Air Suspension System Does Not OperateEES0011D
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. Turn ignition switch OFF.
4. 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: August 20072004 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 OnEES0011E
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-31, "
WARNING LAMPS" . Voltage : Approx. 12V
WEIA0071E

REAR SUSPENSION ASSEMBLY
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Revision: August 20072004 QX56
REAR SUSPENSION ASSEMBLYPFP:55020
ComponentsEES0011F
Rear Suspension
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