Page 2857 of 3383

RSU-18
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: November 20092006 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. Disconnect suspension control unit connector B3 and height sensor C8.
2. Check the terminals for deformation, disconnection, looseness or damage.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace as necessary.
4. CHECK HEIGHT SENSOR POWER
1. Reconnect the suspension control unit connector.
2. Turn the ignition switch ON.
3. Check voltage between height sensor connector C8 terminal 1 and ground.
OK or NG
OK >> GO TO 5.
NG >> Check harness or connector for open or short. If OK, replace suspension control unit. Refer to RSU-47,
"CONTROL UNIT" .
Self-diagnosis results
C1801
C1806
C1807
HEIGT SEN 0.2V - 4.8V
Voltage: Approx. 5V
WEIA0084E
Page 2858 of 3383

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMSRSU-19
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
5. CHECK HEIGHT SENSOR GROUND
1. Turn ignition switch OFF.
2. Check continuity between height sensor connector C8 terminal 3 and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.
6. CHECK HEIGHT SENSOR SIGNAL CIRCUIT
1. Disconnect suspension control unit connector.
2. Check continuity between height sensor connector C8 terminal 2 and suspension control unit connector B3 terminal 3.
3. Check continuity between height sensor connector C8 terminal 2 and ground.
OK or NG
OK >> Replace the height sensor. Refer to RSU-45, "HEIGHT
SENSOR" .
NG >> Repair harness or connector.
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. 3 - Ground
Continuity should exist.
WEIA0085E
2 - 3 Continuity should exist.
WEIA0086E
2 - GroundContinuity should not exist.
WEIA0087E
Self-diagnosis results
C1803
C1805
Page 2859 of 3383

RSU-20
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: November 20092006 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 "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.
5. EXHAUST VALVE SOLENOID INSPECTION
Apply 12V to suspension air compressor terminal 2 and ground to
suspension air compressor terminal 1.
OK or NG
OK >> GO TO 6.
NG >> Replace the suspension air compressor. Refer to RSU-
43, "REAR LOAD LEVELING AIR SUSPENSION COM-
PRESSOR ASSEMBLY" .
System air pressure should vent.
WEIA0063E
Page 2860 of 3383

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMSRSU-21
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
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 and ground.
4. Turn ignition switch OFF.
5. Check continuity between suspension air compressor connector C9 terminal 1 and ground.
OK or NG
OK >> Replace the suspension control unit. Refer to RSU-47,
"CONTROL UNIT" .
NG >> Repair harness or connector.
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.
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. Voltage
: Approx. 12V
WEIA0088E
1 - GroundContinuity should exist.
WEIA0089E
Self-diagnosis results
C1802
C1804
C1808
Page 2861 of 3383

RSU-22
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMS
Revision: November 20092006 QX56
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 terminal 2 and ground to
suspension air compressor terminal 1.
OK or NG
OK >> GO TO 6.
NG >> Replace the suspension air compressor. Refer to RSU-
43, "REAR LOAD LEVELING AIR SUSPENSION COM-
PRESSOR ASSEMBLY" .
System air pressure should vent.
WEIA0066E
Page 2862 of 3383
TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMSRSU-23
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
6. CHECK SUSPENSION AIR COMPRESSOR POWER AND GROUND
1. Connect suspension control unit connector B3.
2. Turn the ignition switch ON.
3. Check voltage between suspension air compressor connector C9 terminal 2 and ground.
4. Turn ignition switch OFF.
5. Check continuity between suspension air compressor connector C9 terminal 1 and ground.
OK or NG
OK >> Replace the suspension control unit. Refer to RSU-47,
"CONTROL UNIT" .
NG >> Repair harness or connector. Voltage
: Approx. 12V
WEIA0090E
1 - GroundContinuity should exist.
WEIA0091E
Page 2863 of 3383

RSU-24
TROUBLE DIAGNOSES FOR SYMPTOMS
Revision: November 20092006 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 AND FUSIBLE LINK
Check that the following fuses and fusible link are not blown.
OK or NG
OK >> GO TO 3.
NG >> If fuse or fusible link is blown, be sure to eliminate cause of malfunction before installing new fuse or fusible link. 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 and ground and between suspension control unit con-
nector B3 terminal 7 and ground.
3. Turn the ignition switch OFF.
4. Check continuity between suspension control unit connector B3 terminal 16 and ground.
OK or NG
OK >> GO TO 4.
NG >> Repair harness or connector.
Unit Terminals Signal nameFuse and fusible link No.
Suspension control unit 6
Ignition switch ON or START 12 (10A)
7 Battery power 29 (10A)
Compressor motor relay 5 g (30A)
Combination meter 24
Ignition switch ON or START 14 (10A)
8 Battery power 19 (10A)
Voltage: Approx. 12V
WEIA0069E
16 - Ground Continuity should exist.
WEIA0070E
Page 2864 of 3383
TROUBLE DIAGNOSES FOR SYMPTOMSRSU-25
C
DF
G H
I
J
K L
M A
B
RSU
Revision: November 2009 2006 QX56
4. CHECK GENERATOR SIGNAL INPUT
1. Start the engine.
2. Check voltage between suspension control unit connector B3 terminal 15 and ground.
OK or NG
OK >> Replace the suspension control unit. Refer to RSU-47,
"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-31, "
WARNING LAMPS" .
Voltage : Approx. 12V
WEIA0071E