height INFINITI QX56 2008 Factory Service Manual

SCS-34
< ECU DIAGNOSIS >
SUSPENSION CONTROL UNIT
Compressor relay [C1802]• Driving transistor for compre
ssor relay is OFF and monitor
voltage continues at a high level for more than 10 seconds.
• Driving transistor for compressor relay is ON and monitor volt-
age continues at a low level for more than 5 seconds. SCS-10, "DiagnosisProcedure"
Exhaust solenoid [C1803]
• Driving transistor for exhaust valve solenoid is OFF and mon-
itor voltage continues at a high level for more than 10 seconds.
• Driving transistor for exhaust valve solenoid is ON and monitor voltage continues at a low level for more than 5 secondsl. SCS-11, "DiagnosisProcedure"
Vehicle height adjusting malfunction
(compressor)[C1804]
Continuous compressor relay ON time is more than 120 sec-
onds. SCS-12,
"DiagnosisProcedure"
Vehicle height adjusting malfunction
(exhaust solenoid)[C1805]Continuous exhaust valve solenoid ON time is more than 120
seconds. SCS-13,
"DiagnosisProcedure"
Vehicle height sensor locking mal-
function [C1806]Output sensor voltage variation
±0.02V is more than 100 sec-
onds when vehicle height range is normal. SCS-14, "Diagnosis Pro-
cedure"
Sensor 5V malfunction [C1807]
Sensor reference voltage is less than 0.8V or more than 6V for
20 seconds. SCS-15, "DiagnosisProcedure"
Integral time malfunction by supply-
ing air [C1808]A suspension air compressor ON request has been in effect for
180 seconds and the suspension air compressor has not activat-
ed during that time. SCS-16,
"DiagnosisProcedure"
Revision: March 2010
2008 QX56

SUSPENSION CONTROL SYSTEMSCS-35
< SYMPTOM DIAGNOSIS >
C
DF
G H
I
J
K L
M A
B
SCS
N
O P
SYMPTOM DIAGNOSIS
SUSPENSION CONTROL SYSTEM
Symptom TableINFOID:0000000001732002
AIR LEVELIZER
Symptom Possible causeReference page
Inoperative • Suspension control unit
• Compressor motor relay
• Suspension air compressorSCS-36, "
Diagnosis
Procedure"
System does not raise• Suspension control unit
• Height sensor
• Compressor motor relay
• Suspension air compressor
• Leak in system
• Restriction in systemSCS-37, "Diagnosis
Procedure"
System does not lower
• Suspension control unit
• Height sensor
• Compressor motor relay
• Suspension air compressor
• Restriction in systemSCS-38, "Diagnosis
Procedure"
CK SUSP indicator lamp
always ON with key ON • CK SUSP indicator lamp control circuit
• Suspension control unit SCS-25, "Descrip-
tion"
Revision: March 2010
2008 QX56

SCS-36
< SYMPTOM DIAGNOSIS >
SUSPENSION CONTROL SYSTEM INOPERATIVE
SUSPENSION CONTROL SYSTEM INOPERATIVE
DescriptionINFOID:0000000001732003
The suspension control system does not activate. It does not raise or lower the vehicle in response to ride
height changes.
Diagnosis ProcedureINFOID:0000000001732004
1.SUSPENSION CONTROL UNIT PO WER AND GROUND INSPECTION
Check the suspension control unit power and ground supply. Refer to SCS-17, "
SUSPENSION CONTROL
UNIT : Diagnosis Procedure".
Does the suspension control unit power and ground pass inspection?
YES >> GO TO 2
NO >> Repair or replace the malfunctioning part.
2.CHECK HEIGHT SENSOR SIGNAL INPUT
CONSULT-III DATA MONITOR
1. Turn ignition switch ON.
2. Select "HEIGT SEN" of AI R LEVELIZER data monitor item.
3. Check the monitor status.
Is the height sensor voltage normal?
YES >> GO TO 3
NO >> Check height sensor signal circuit. Refer to SCS-22, "
Diagnosis Procedure" .
3.CHECK GENERATOR "L" CIRCUIT SIGNAL
CONSULT-III DATA MONITOR
1. Start the engine.
2. Select "ACG L" of AIR LE VELIZER data monitor item.
3. Check the monitor status.
Is the generator "L" signal operating normally?
YES >> GO TO 4.
NO >> Check generator L circuit. Refer to CHG-14, "
Diagnosis Procedure"
4.SUSPENSION AIR COMPRESSOR POWER AND GROUND INSPECTION
Check the suspension air compressor power and ground supply. Refer to SCS-17, "
SUSPENSION AIR COM-
PRESSOR : Diagnosis Procedure".
Does the suspension air compressor power and ground pass inspection?
YES >> System is operating normally.
NO >> Repair or replace the malfunctioning part. HEIGT SEN
: 0.2V - 4.8V
ACG L: OFF with charge light OFF
: ON with charge light ON
Revision: March 2010
2008 QX56

SUSPENSION CONTROL SYSTEM DOES NOT RAISE
SCS-37
< SYMPTOM DIAGNOSIS >
C
D F
G H
I
J
K L
M A
B
SCS
N
O P
SUSPENSION CONTROL SYST EM DOES NOT RAISE
DescriptionINFOID:0000000001732005
The suspension control system does not raise the vehicle in accordance with ride height changes.
Diagnosis ProcedureINFOID:0000000001732006
1.SUSPENSION CONTROL UNIT PO WER AND GROUND INSPECTION
Check the suspension control unit power and ground supply. Refer to SCS-17, "
SUSPENSION CONTROL
UNIT : Diagnosis Procedure".
Does the suspension control uni t power and ground pass inspection?
YES >> GO TO 2
NO >> Repair or replace the malfunctioning part.
2.CHECK HEIGHT SENSOR SIGNAL INPUT
CONSULT-III DATA MONITOR
1. Turn ignition ON.
2. Select "HEIGT SEN" of AI R LEVELIZER data monitor item.
3. Check the monitor status.
Is the height sensor voltage normal?
YES >> GO TO 3
NO >> Check height sensor signal circuit. Refer to SCS-22, "
Diagnosis Procedure" .
3.SUSPENSION AIR COMPRESSOR POWER AND GROUND INSPECTION
Check the suspension air compressor power and ground supply. Refer to SCS-17, "
SUSPENSION AIR COM-
PRESSOR : Diagnosis Procedure".
Does the suspension air compress or power and ground pass inspection?
YES >> Inspect for a weak compressor, leak or restriction in the system. Repair or replace malfunctioning
part.
NO >> Repair or replace the malfunctioning part. HEIGT SEN
: 0.2V - 4.8V
Revision: March 2010 2008 QX56

SCS-38
< SYMPTOM DIAGNOSIS >
SUSPENSION CONTROL SYSTEM DOES NOT LOWER
SUSPENSION CONTROL SYSTEM DOES NOT LOWER
DescriptionINFOID:0000000001732007
The suspension control system does not lower the vehicle in accordance with ride height changes.
Diagnosis ProcedureINFOID:0000000001732008
1.SUSPENSION CONTROL UNIT PO WER AND GROUND INSPECTION
Check the suspension control unit power and ground supply. Refer to SCS-17, "
SUSPENSION CONTROL
UNIT : Diagnosis Procedure".
Does the suspension control unit power and ground pass inspection?
YES >> GO TO 2
NO >> Repair or replace the malfunctioning part.
2.CHECK HEIGHT SENSOR SIGNAL INPUT
CONSULT-III DATA MONITOR
1. Turn ignition ON.
2. Select "HEIGT SEN" of AI R LEVELIZER data monitor item.
3. Check the monitor status.
Is the height sensor voltage normal?
YES >> GO TO 3
NO >> Check height sensor signal circuit. Refer to SCS-22, "
Diagnosis Procedure" .
3.EXHAUST VALVE SOLENOID CIRCUIT INSPECTION
Check the exhaust valve solenoid circuit. Refer to SCS-23, "
Component Function Check".
Does the exhaust valve solenoid circuit pass inspection?
YES >> Inspect for a restriction in the system . repair or replace the malfunctioning part.
NO >> Repair or replace the malfunctioning part. HEIGT SEN
: 0.2V - 4.8V
Revision: March 2010 2008 QX56

CONTROL VALVE WITH TCMTM-203
< ON-VEHICLE REPAIR >
CEF
G H
I
J
K L
M A
B
TM
N
O P
10. Remove bolts (A), (B) and (C) from control valve with TCM.
11. Remove control valve with TCM from transmission case. CAUTION:
When removing, be careful with the manual valve notch and
manual plate height. Remove it vertically.
12. Remove the A/T fluid temperature sensor 2 or plug as shown below.
a. A/T fluid temperature sensor 2
i. Remove A/T fluid temperature sensor 2 with bracket from con- trol valve with TCM.
ii. Remove bracket from A/T fluid temperature sensor 2.
b. Plug
: Front
Bolt symbol Length mm (in) Number of bolts
A 42 (1.65) 5
B 55 (2.17) 6
C 40 (1.57) 1
SCIA8074E
SCIA5142E
SCIA5253E
SCIA5264E
Revision: March 2010 2008 QX56

DISASSEMBLYTM-239
< DISASSEMBLY AND ASSEMBLY >
CEF
G H
I
J
K L
M A
B
TM
N
O P
33. Disconnect output speed sensor connector (1). CAUTION:
Do not damage connector.
34. Straighten terminal clip ( ) to free output speed sensor har- ness.
35. Remove bolts (A), (B) and (C) from control valve with TCM. • : Front
36. Remove control valve with TCM from transmission case. CAUTION:
When removing, be careful with the manual valve notch and
manual plate height. Remove it vertically.
37. Remove A/T fluid temperature sensor 2 with bracket from con- trol valve with TCM.
JSDIA1319ZZ
JSDIA1320ZZ
Bolt symbol Length mm (in) Number of bolts
A 42 (1.65) 5
B 55 (2.17) 6
C 40 (1.57) 1
SCIA8077E
SCIA5260E
SCIA5301E
Revision: March 2010 2008 QX56