2008 INFINITI QX56 relay

SCS-12
< COMPONENT DIAGNOSIS >
C1804 HEIGHT ADJUSTING MALFUNCTION (COMPRESSOR)
C1804 HEIGHT ADJUSTING MA LFUNCTION (COMPRESSOR)
DescriptionINFOID:0000000001731969
The compressor motor relay is controlled by the sus pension control unit. The suspension control unit supplies
voltage to the coil side of the relay to activate it. T he compressor motor relay, when activated, supplies power
to the suspension air compressor.
DTC LogicINFOID:0000000001731970
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000001731971
1.CHECK COMPRESSOR MOTOR RELAY OPERATION
CAUTION:
The "COMPRESSOR" active test will remain ON until it is turned off using CONSULT-III. Allowing the
compressor to run for an extended period of time may cause damage to the air levelizer system com-
ponents due to excessive air pressure.
CONSULT-III
1. Turn ignition ON.
2. Select "COMPRESSOR" of AIR LEVELIZER active test items.
3. While operating test item, check that the suspension air compressor turns ON.
Does the suspension air compressor operate properly?
YES >> Compressor motor relay and suspension air compressor are operating normally.
NO >> Refer to SCS-20, "
Diagnosis Procedure"
DTCDisplay contents of CON-
SULT-III Diagnostic item is detected when ...
Probable malfunction location
C1804 VEHICLE HEIGHT AD-
JUSTING MALFUNC-
TION (COMPRESSOR) Continuous compressor relay ON time is more
than 120 seconds.
Compressor motor relay. Refer to
SCS-20,
"Component Function Check"
ON : Compressor turns ON
OFF : Compressor turns OFF
Revision: March 2010 2008 QX56

SCS-16
< COMPONENT DIAGNOSIS >
C1808 INTEGRAL TIME MALFUNCTION SUPPLYING AIR
C1808 INTEGRAL TIME MALFUNCTION SUPPLYING AIR
DescriptionINFOID:0000000001731981
The suspension air compressor is supplied power by the compressor motor relay. The suspension control unit
supplies power to the compressor motor relay in order to activate the relay and subsequently activate the sus-
pension air compressor.
DTC LogicINFOID:0000000001731982
DTC DETECTION LOGIC
Diagnosis ProcedureINFOID:0000000001731983
1.CHECK COMPRESSOR MOTOR RELAY OPERATION
CAUTION:
The "COMPRESSOR" active test will remain ON until it is turned off using CONSULT-III. Allowing the
compressor to run for an extended period of time may cause damage to the air levelizer system com-
ponents due to excessive air pressure.
CONSULT-III
1. Turn ignition ON.
2. Select "COMPRESSOR" of AIR LEVELIZER active test items.
3. While operating test item, check that the suspension air compressor turns ON.
Does the suspension air compressor operate properly?
YES >> Compressor motor relay and suspension air compressor are operating normally.
NO >> Refer to SCS-20, "
Diagnosis Procedure"
DTCDisplay contents of CON-
SULT-III Diagnostic item is detected when ...
Probable malfunction location
C1808 INTEGRAL TIME MAL-
FUNCTION SUPPLYING
AIR A suspension air compressor ON request has
been in effect for 180 seconds and the suspen-
sion air compressor has not activated during
that time. • Compressor motor relay. Refer to
SCS-20,
"Diagnosis Procedure"
• Suspension air compressor. Refer to SCS-
17, "SUSPENSION AIR COMPRESSOR :
Diagnosis Procedure"
ON : Compressor turns ON
OFF : Compressor turns OFF
Revision: March 2010 2008 QX56

POWER SUPPLY AND GROUND CIRCUITSCS-17
< COMPONENT DIAGNOSIS >
C
DF
G H
I
J
K L
M A
B
SCS
N
O P
POWER SUPPLY AND GROUND CIRCUIT
SUSPENSION CONTROL UNIT
SUSPENSION CONTROL UNIT : Diagnosis ProcedureINFOID:0000000001731984
1.CHECK FUSES
Check that the following fuses of the sus pension control unit are not are not blown.
Are the fuses OK?
YES >> GO TO 2
NO >> If fuse is blown, be sure to eliminate cause of malfunction before installing new fuse.
2.POWER SUPPLY CIRCUIT CHECK
1. Disconnect suspension control unit connector B3.
2. Check voltage between the suspension control unit connector B3 and ground.
Are the voltage results as specified?
YES >> GO TO 3
NO >> • Check connector housings for disconnected or loose terminals. • Repair harness or connector.
3.GROUND CIRCUIT CHECK
1. Turn ignition switch OFF.
2. Check continuity between suspension control unit harness con- nector B3 and ground.
Is continuity present?
YES >> Inspection End.
NO >> Repair harness or connector.
SUSPENSION AIR COMPRESSOR
SUSPENSION AIR COMPRESSOR : Diagnosis ProcedureINFOID:0000000001731985
1.CHECK COMPRESSOR MOTOR RELAY OPRATION
CONSULT-III
Unit Terminals Signal name Fuse No.
Suspension control unit 7
Battery power 29
6 Ignition switch ON or START 12
(+)
(-) OFF ACC ON START
Connector Terminal
B3 7Ground
Battery
voltage Battery
voltage Battery
voltage Battery
voltage
6Ground0V 0V Battery
voltage Battery
voltage
ALEIA0027GB
Connector Terminal —Continuity
B3 16Ground Yes
ALEIA0028GB
Revision: March 2010 2008 QX56

SCS-18
< COMPONENT DIAGNOSIS >
POWER SUPPLY AND GROUND CIRCUIT
1. Disconnect the suspension air compressor connector C9.
2. Turn ignition switch ON.
3. Select "COMPRESSOR" under AIR LEVELIZER active testitems.
4. While operating the test item, check voltage at the suspension
air compressor connector C9 terminal 4.
Is battery voltage present?
YES >> GO TO 3.
NO >> GO TO 2.
2.COMPRESSOR MOTOR RELAY POWER SUPPLY CIRCUIT CHECK
1. Turn ignition switch OFF.
2. Disconnect the compressor motor relay connector.
3. Check continuity between compressor motor relay connector E131 (A) terminal 3 and suspension air compressor connector
C9 (B) terminal 4.
4. Check continuity between compressor motor relay connector E131 (A) terminal 3 and ground.
Are the continuity test results as specified?
YES >> Check compressor motor relay. Refer to SCS-20, "Diagnosis Procedure"
NO >> Repair harness or connector.
3.GROUND CIRCUIT CHECK
1. Turn ignition switch OFF.
2. Check continuity between suspension air compressor connector C9 terminals 1 and 3 and ground.
Is continuity present?
YES >> Inspection End.
NO >> Repair harness or connector.
HEIGHT SENSOR
HEIGHT SENSOR : Dia gnosis ProcedureINFOID:0000000001731986
1.POWER SUPPLY CIRCUIT CHECK
(+)
(-)Voltage
Connector Terminal
C9 4Ground Battery Voltage
ALEIA0021GB
AB
Continuity
Connector Terminal Connector Terminal
E131 3 C9 4 Yes
A —Con tin uit y
Connector Terminal
E131 3Ground No
ALEIA0022GB
Connector Terminal —Continuity
C9 1
Ground Yes
3
ALEIA0023GB
Revision: March 2010 2008 QX56

SCS-20
< COMPONENT DIAGNOSIS >
COMPRESSOR MOTOR RELAY
COMPRESSOR MOTOR RELAY
DescriptionINFOID:0000000001731987
Receives suspension air compressor ON signal from suspension control unit. When activated, the compressor
motor relay supplies power to the suspension air compressor.
Component Function CheckINFOID:0000000001731988
1.CHECK COMPRESSOR MOTOR RELAY OPERATION
CAUTION:
The "COMPRESSOR" active test will remain ON until it is turned off using CONSULT-III. Allowing the
compressor to run for an extended period of time may cause damage to the suspension control sys-
tem components due to excessive air pressure.
CONSULT-III
1. Turn ignition ON.
2. Select "COMPRESSOR" of AIR LEVELIZER active test items.
3. While operating test item, check that the suspension air compressor turns ON.
Does the suspension air compressor operate properly?
YES >> Compressor motor relay and suspension air compressor are operating normally.
NO >> Refer to SCS-20, "
Diagnosis Procedure"
Diagnosis ProcedureINFOID:0000000001731989
1.CHECK COMPRESSOR "ON" SIGNAL FROM SUSPENSION CONTROL UNIT
CONSULT-III
1. Turn ignition switch ON.
2. Disconnect compressor motor relay connector E130.
3. Select "COMPRESSOR" of AIR LEVELIZER active test items.
4. While operating test item, check voltage to compressor motor relay connector E130 terminal 2.
Is battery voltage present while operating test item?
YES >> GO TO 3.
NO >> GO TO 2.
2.CHECK COMPRESSOR "ON" SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect suspension control unit connector B3.
3. Check continuity between suspension control unit connector B3 (A) terminal 1 and compressor motor relay connector E130 (B)
terminal 2.
4. Check continuity between suspension control unit connector B3 (A) terminal 1 and ground.ON : Compressor turns ON
OFF : Compressor turns OFF
(+)
(-)Voltage
Connector Terminal
E130 2Ground Battery voltage
ALEIA0030GB
AB
Continuity
Connector Terminal Connector Terminal
B3 1E 1302 Y es
ALEIA0031GB
Revision: March 2010 2008 QX56

COMPRESSOR MOTOR RELAYSCS-21
< COMPONENT DIAGNOSIS >
C
DF
G H
I
J
K L
M A
B
SCS
N
O P
Are the continuity test results as specified?
YES >> Replace the suspension control unit. Refer to RSU-25, "Removal and Installation"
NO >> Repair harness or connector.
3.CHECK COMPRESSOR MOTOR RELAY GROUND
1. Turn ignition switch OFF.
2. Check continuity between compressor motor relay connector E130 terminal 1 and ground.
Is continuity present?
YES >> GO TO 4.
NO >> Repair harness or connector.
4.CHECK COMPRESSOR MOTOR RELAY POWER SUPPLY
1. Disconnect compressor motor relay connector E131.
2. Check voltage between compressor motor relay E131 terminal 5 and ground.
Is battery voltage present?
YES >> GO TO 5.
NO >> Inspect fuse and repair harness or connector.
5.CHECK COMPRESSOR MOTOR RELAY OUTPUT
1. Connect compressor motor relay connectors E130 and E131.
2. Disconnect suspension air compressor connector C9.
3. Turn ignition ON.
4. Select "COMPRESSOR" of AIR LEVELIZER active test items.
5. Check voltage between compressor motor relay C9 terminal 4 and ground.
Is battery voltage present?
YES >> Compressor motor relay is functioning properly.
NO >> GO TO 6.
6.CHECK AIR COMPRESSOR POWER SUPPLY CIRCUIT
Check the air compressor power supply circuit. Refer to SCS-17, "
SUSPENSION AIR COMPRESSOR : Diag-
nosis Procedure"
Does the power supply circuit test OK?
YES >> Replace the compessor motor relay.
NO >> Repair harness or connector.
A — Continuity
Connector Terminal
B3 1 Ground No
Connector Terminal —Continuity
E130 1Ground Yes
ALEIA0032GB
(+)
(-)Voltage
Connector Terminal
E131 5Ground Battery voltage
ALEIA0033GB
(+)
(-)Voltage
Connector Terminal
C9 4Ground Battery voltage
ALEIA0034GB
Revision: March 2010 2008 QX56

SUSPENSION CONTROL UNITSCS-27
< ECU DIAGNOSIS >
C
DF
G H
I
J
K L
M A
B
SCS
N
O P
ECU DIAGNOSIS
SUSPENSION CONTROL UNIT
Reference ValueINFOID:0000000001731999
TERMINAL LAYOUT
PHYSICAL VALUES
ALNIA0660GB
Te r m i n a l
(Wire color) Description
ConditionReference value
(Approx.)
+ – Signal nameInput/
Output
1
(V) Ground Compressor relay output Output Ignition
switch
ON Air levelizer ra
ising vehicle
ride height Battery voltage
3
(W) Ground Height sensor input
InputIgnition
switch ON —
0.2V - 4.8V
5
(R) Ground VREF output (height sen-
sor) OutputIgnition
switch ON —5
V
6
(G/R) Ground IGN power supply
InputIgnition
switch
ON or
START —
Battery voltage
7
(W/L) Ground BAT power supply
InputIgnition
switch
OFF —
Battery voltage
8
(G/W) Ground Diagnostic K-line Input/
Output ——
—
9
(SB) Ground Exhaust valve output Output Ignition
switch ON Air levelizer lo
wering vehi-
cle ride height (venting) Battery voltage
10
(BR) Ground Warning lamp output Output Ignition
switch ON Warning lamp ON
0V
Warning lamp OFF Battery voltage
14
(L) Ground Height sensor ground Output Ignition
switch
ON —
Less than 0.2V
15
(BR/W) Ground Generator input
InputIgnition
switch ON Charge light ON
0V
Charge light OFF Battery voltage
16
(B) Ground Suspension control unit
ground InputIgnition
switch ON —
Less than 0.2V
Revision: March 2010 2008 QX56

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