2006 INFINITI QX56 suspension

RSU-12
TROUBLE DIAGNOSIS
Revision: November 20092006 QX56
Basic InspectionEES001H6
AIR HOSES
1. Check for pinched or damaged air hoses between the suspension air reservoir and each load leveling rear
air suspension shock absorber. Reposition, repair or replace hoses as necessary.
2. Check the air hose connections at the suspension air reservoir and at the shock absorbers for leaks. If connections are leaking, repair or replace hoses as necessary.
POWER SYSTEM TERMINAL LOOSENESS AND BATTERY INSPECTION
Make sure the battery positive cable, negative cable and ground connection are not loose. In addition, make
sure the battery is sufficiently charged.
CK SUSP INDICATOR LAMP INSPECTION
1. Make sure the CK SUSP indicator lamp turns on for approximately 2 seconds when the ignition switch is
turned ON. If it does not, check the combination meter. Refer to DI-5, "
COMBINATION METERS" .
2. Make sure the lamp turns off approximately 2 seconds after the ignition switch is turned ON. If the lamp does not turn off, conduct self-diagnosis of the suspension control unit.
3. After conducting the self-diagnosis, be sure to erase the error memory. Refer to RSU-13, "
CONSULT-II
Function (AIR LEVELIZER)" .
CK SUSP Indicator Lamp TimingEES001H7
X: ON
—: OFF
Control Unit Input/Output Signal StandardEES001H8
ConditionCK SUSP
indicator lamp Remarks
Ignition switch OFF ––
Ignition switch ON X Turns off after approximately 2 seconds.
Te r m i n a l
No. Wire color
Item ConditionVoltage (V)
(Approx.)
1 V Compressor relay output
Ignition switch ON or STARTBattery voltage
3 W Height sensor signal input 0.2V - 4.8V
5 R Reference voltage 5V
6 G/R Ignition power
Battery voltage
7W /LB atte ry p ow er —
8 G/W Diagnostic K-line ——
9 SB Exhaust valve output Ignition switch ON or STARTBattery voltage
10 BR Warning lamp output ——
14 L Height sensor ground ——
15 BR/W Generator L signal input Engine running—
16 B Suspension control unit ground —0V

TROUBLE DIAGNOSISRSU-13
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CONSULT-II Function (AIR LEVELIZER)EES001H9
CONSULT-II can display each diagnostic item using the diagnostic test modes shown following.
CONSULT-II OPERATION
1. Turn ignition switch OFF.
2. Connect CONSULT-II and CONSULT-II CONVERTER to the
data link connector.
CAUTION:
If CONSULT-II is used with no connection of CONSULT-II
CONVERTER, malfunctions might be detected in self-diag-
nosis depending on control unit which carries out CAN
communication.
3. Turn ignition switch ON.
4. Touch "START (NISSAN BASED VHCL)".
5. Touch "AIR LEVELIZER" in the "SELECT SYSTEM" screen. If "AIR LEVELIZER" is not indicated, go to GI-40, "
CONSULT-II
Data Link Connector (DLC) Circuit" .
AIR LEVELIZER
diagnostic mode Description
WORK SUPPORT Supports inspections and adjustments. Commands are transmitted to the BCM for setting the status
suitable for required operation, input/output signals are received from the BCM and received data is
displayed.
SELF-DIAG RESULTS Displays suspension control unit self-diagnosis results. DATA MONITOR Displays suspension control unit input/output data in real time.ACTIVE TEST Operation of electrical loads can be checked by sending drive signal to them.
ECU PART NUMBER Suspension control unit part number can be read.
BBIA0369E
BCIA0029E
BCIA0030E

TROUBLE DIAGNOSISRSU-15
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WORK SUPPORT
Operation Procedure
1. After turning OFF the ignition switch, connect CONSULT-II and the CONSULT-II CONVERTER to the data
link connector.
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)", "AIR LEVELIZER", "WORK SUPPORT" in order on the CON- SULT-II screen.
If "AIR LEVELIZER" is not indicated, go to GI-40, "
CONSULT-II Data Link Connector (DLC) Circuit" .
CAUTION:
When "START (NISSAN BASED VHCL)" is touched immediately after starting the engine or turning
on the ignition switch, "AIR LEVELIZER" might not be displayed in the "SELECT SYSTEM" screen.
In this case, repeat the operation from step 2.
3. Select "STANDARD HEIGHT LEVEL", "ADJUST HEIGHT INI" or "CLEAR HEIGHT INI" on the "SELECT WORK ITEM" screen.
NOTE:
Read and perform screen instructions if "STANDARD HEIGHT LEVEL" or "ADJUST HEIGHT INI" is
selected.
4. Touch "START" to begin the desired work support.
Display Item List
Vehicle height adjusting trouble
(compressor)
[C1804] Continuous compressor relay ON time is more than 120 sec-
onds. Refer to
RSU-21, "Compres-
sor Motor, Compressor
Motor Relay and Circuit
Inspection" .
Vehicle height adjusting trouble
(exhaust solenoid)
[C1805] Continuous exhaust solenoid ON time is more than 120 seconds. Refer to
RSU-19, "
Exhaust
Valve Solenoid System
Inspection" .
Vehicle height sensor locking trou-
ble
[C1806] Output sensor voltage variation ±
0.02V is more than 100 hour
when vehicle height range is normal. Refer to
RSU-18, "
Height
Sensor System Inspection" .
Sensor 5V trouble
[C1807] Sensor reference voltage is less than 0.8V or more than 6V for
20 seconds. Refer to
RSU-18, "
Height
Sensor System Inspection" .
Integral time trouble by supplying
air
[C1808] Integral discontinuous time on the compressor is more than 180
seconds. Refer to
RSU-21, "
Compres-
sor Motor, Compressor
Motor Relay and Circuit
Inspection" .
Self-diagnostic item
Malfunction detecting condition Check system
ItemDescription Condition
STANDARD HEIGHT LEVEL Resets the vehicle height to the initialization flag
setting stored in the suspension control unit. Vehicle unladen
RSU-49, "
Wheelarch Height
(Unladen*1 )" , set in a horizontal position and
not moving.
NOTE:
Do not take your eyes off the vehicle while
CONSULT-II is processing.
ADJUST HEIGHT INI Sets the height initialization flag in the suspension
control unit when the control unit has been replaced
or when the initialization flag has been cleared
using the "CLEAR HEIGHT INI" procedure. Vehicle unladen
RSU-49, "
Wheelarch Height
(Unladen*1 )" . Move vehicle forward and
backward approx. 5 m (16.4 ft) and rock vehi-
cle from side to side.
NOTE:
Do not move vehicle while CONSULT-II is pro-
cessing.
CLEAR HEIGHT INI Clears the initialization flag in the suspension con-
trol unit. Vehicle unladen
RSU-49, "
Wheelarch Height
(Unladen*1 )" .

TROUBLE DIAGNOSISRSU-17
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Revision: November 2009 2006 QX56
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.
EXHAUST SOLENOIDOFF/ON
WARNING LAMP OFF/ON
Test Item
Description

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

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMSRSU-19
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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

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

TROUBLE DIAGNOSIS FOR SELF-DIAGNOSTIC ITEMSRSU-21
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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