check engine INFINITI QX56 2004 Factory Service Manual

RSU-12
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
Basic InspectionEES00116
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 TimingEES00117
X: ON
—: OFF
Control Unit Input/Output Signal StandardEES00118
( ): Wire colorConditionCK SUSP
indicator lampRemarks
Ignition switch OFF – –
Ignition switch ON X Turns off after approximately 2 seconds.
Te r m i n a l
Item ConditionVoltage (V)
(Approx.)
+–
1 (V)
GroundCompressor 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
7 (W/L) Battery power —
8 (G/W) Diagnostic K-line — —
9 (SB) Exhaust valve output Ignition switch ON or START Battery voltage
10 (BR) Warning lamp output — —
14 (L) Height sensor ground — —
15 (BR/W) Alternator L signal input Engine running —
16 (B) Suspension control unit ground — 0V

RSU-14
TROUBLE DIAGNOSIS
Revision: August 20072004 QX56
6. Select the required operation from the "SELECT DIAG MODE"
screen.
For further information, see the CONSULT-II Operation Manual.
WORK SUPPORT
Operation Procedure
1. Touch “AIR LEVELIZER” on “SELECT SYSTEM” screen.
2. Touch “WORK SUPPORT” on “SELECT DIAG MODE” screen.
3. Touch item on “SELECT WORK ITEM” screen.
4. Touch “START”.
5. The setting will be changed and “ADJUSTMENT COMPLETE” will be displayed.
6. Touch “END”.
Display Item List
SELF-DIAGNOSIS
Description
If an error is detected in the system, perform self-diagnosis as follows:
Operation Procedure
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-diagnosis depending on control unit which carries out CAN communication.
3. Turn ignition switch ON.
4. After stopping the vehicle, with the engine running, touch “START (NISSAN BASED VHCL)”, "AIR LEVEL-
IZER", “SELF-DIAG RESULTS” in order on the CONSULT-II screen.
CAUTION:
If “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 1.
5. The self-diagnostic results are displayed. (If necessary, the self-diagnostic results can be printed out by
touching “COPY”.)

When “NO DTC IS DETECTED” is displayed, check the CK SUSP indicator lamp.
6. Conduct the appropriate inspection from the display item list, and repair or replace the malfunctioning
component.
7. Start and run the vehicle for approximately 1 minute.
8. Turn ignition switch OFF to prepare for erasing the memory.
9. Start the engine and touch “START (NISSAN BASED VHCL)”, "AIR LEVELIZER", “SELF-DIAG
RESULTS”, “ERASE” in order on the CONSULT-II screen to erase the error memory.
If "AIR LEVELIZER" is not indicated, go to GI-39, "
CONSULT-II Data Link Connector (DLC) Circuit" .
BCIA0031E
Item Description
STANDARD HEIGHT LEVEL This mode allows the vehicle height to be set to vehicle height specification within tolerance.
ADJUST HEIGHT INI The initialization value and flag can be set in the suspension control unit in this mode.
CLEAR HEIGHT INI This mode clears the initialization flag and value in the suspension control unit.

TROUBLE DIAGNOSIS
RSU-15
C
D
F
G
H
I
J
K
L
MA
B
RSU
Revision: August 20072004 QX56
CAUTION:
If the error memory is not erased, re-conduct the operation from step 7.
10. For the final inspection, start and run the vehicle for approximately 1 minute and confirm that the CK
SUSP indicator lamp is off.
Display Item List
DATA MONITOR
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", “DATA MONITOR” in order on the CON-
SULT-II screen.
If "AIR LEVELIZER" is not indicated, go to GI-39, "
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. Return to the "SELECT MONITOR ITEM" screen, and touch "ALL SIGNALS" or "SELECTION FROM
MENU". Refer to the following information.
4. When “START” is touched, the data monitor screen is displayed.
Self-diagnostic item Malfunction detecting condition Check system
Vehicle height sensor
[C1801]Vehicle height sensor voltage is less than 0.2V or greater than
4.8V for more than 60 seconds.Refer to RSU-17, "
Height
Sensor System Inspection" .
Compressor relay
[C1802]1. Driving transistor for compressor relay is off and monitor volt-
age continues high level for more than 10 seconds.
2. Driving transistor for compressor relay is on and monitor volt-
age continues low level for more than 5 seconds.Refer to RSU-20, "
Compres-
sor Motor, Compressor
Motor Relay and Circuit
Inspection" .
Exhaust solenoid
[C1803]1. Driving transistor for exhaust solenoid is off and monitor volt-
age continues high level for more than 10 seconds.
2. Driving transistor for exhaust solenoid is on and monitor volt-
age continues low level for more than 5 seconds.Refer to RSU-19, "
Exhaust
Valve Solenoid System
Inspection" .
Vehicle height adjusting trouble
(compressor)
[C1804]Continuous compressor relay ON time is more than 120 sec-
onds.Refer to RSU-20, "
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-17, "
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-17, "
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-20, "
Compres-
sor Motor, Compressor
Motor Relay and Circuit
Inspection" .

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

HEIGHT SENSOR
RSU-45
C
D
F
G
H
I
J
K
L
MA
B
RSU
Revision: August 20072004 QX56
INSTALLATION
Installation is in the reverse order of removal.
1. Start the engine.
2. Use CONSULT-II to perform "STANDARD HEIGHT LEVEL" work support function.
3. Using data monitor of CONSULT-II, verify "HEIGT CALC" is at 0 mm.
4. Check the vehicle height. Refer to RSU-48, "
Wheelarch Height (Unladen*1 )" . If vehicle height is not
within ± 10 mm (0 ± 0.39 in) of the specification, perform the initialization procedure. Refer to RSU-46,
"Initialization Procedure" .

SC-4
BATTERY
Revision: August 20072004 QX56
BATTERYPFP:AYBGL
How to Handle BatteryEKS00795
CAUTION:

If it becomes necessary to start the engine with a booster battery and jumper cables, use a 12-volt
booster battery.

After connecting battery cables, ensure that they are tightly clamped to battery terminals for good
contact.

Never add distilled water through the hole used to check specific gravity.
METHODS OF PREVENTING OVER-DISCHARGE
The following precautions must be taken to prevent over-discharging
a battery.

The battery surface (particularly its top) should always be kept
clean and dry.

The terminal connections should be clean and tight.

At every routine maintenance, check the electrolyte level.
This also applies to batteries designated as “low maintenance”
and “maintenance-free”.

When the vehicle is not going to be used over a long period of
time, disconnect the negative battery terminal.

Check the charge condition of the battery.
Periodically check the specific gravity of the electrolyte. Keep a
close check on charge condition to prevent over-discharge.
CHECKING ELECTROLYTE LEVEL
WAR NIN G:
Do not allow battery fluid to come in contact with skin, eyes, fabrics, or painted surfaces. After touch-
ing a battery, do not touch or rub your eyes until you have thoroughly washed your hands. If acid con-
tacts eyes, skin or clothing, immediately flush with water for 15 minutes and seek medical attention.
MEL040F
MEL041F
MEL042F

SC-14
STARTING SYSTEM
Revision: August 20072004 QX56
DIAGNOSTIC PROCEDURE 1
Check Terminal "2" Circuit
1. CHECK POWER SUPPLY FOR STARTER MOTOR “2” TERMINAL
1. Remove the fuel pump fuse.
2. Crank or start the engine (where possible) until the fuel pressure is released.
3. Turn the ignition switch OFF.
4. Check that the starter motor connector F27 connection is clean and tight.
5. Check voltage between starter motor connector F27 terminal 2
(B/R) and ground using a digital circuit tester.
OK or NG
OK >> GO TO 2.
NG >> Check harness between the battery and the starter
motor for open circuit.
2. CHECK BATTERY CABLE CONNECTION QUALITY (VOLTAGE DROP TEST)
Check voltage between starter motor connector F27 terminal 2 (B/R)
and battery positive terminal using a digital circuit tester.
OK or NG
OK >> GO TO 3.
NG >> Check harness between the battery and the starter
motor for poor continuity.
3. CHECK STARTER MOTOR GROUND CIRCUIT (VOLTAGE DROP TEST)
Check voltage between starter motor case and battery negative ter-
minal using a digital circuit tester.
OK or NG
OK >> Starter motor “2” terminal circuit is OK. Further inspec-
tion is necessary. Refer to SC-13, "
WORK FLOW" .
NG >> Check harness between the starter motor case and
ground for poor continuity. Battery voltage should
exist.
WKIA2105E
Ignition switch in
START.: Less than 0.5V
WKIA2106E
Ignition switch in
START.: Less than 0.2V
WKIA2107E

STARTING SYSTEM
SC-15
C
D
E
F
G
H
I
J
L
MA
B
SC
Revision: August 20072004 QX56
DIAGNOSTIC PROCEDURE 2
Check Terminal "1" Circuit
1. CHECK POWER SUPPLY FOR STARTER MOTOR “1” TERMINAL
1. Remove the fuel pump fuse.
2. Crank or start the engine (where possible) until the fuel pressure is released.
3. Turn the ignition switch OFF.
4. Disconnect starter motor connector F28.
5. Check voltage between starter motor connector F28 terminal 1
(W/R) and ground using a digital circuit tester.
OK or NG
OK >> GO TO 2.
NG >> Check the following.

40A fusible link (letter m , located in fuse and fusible
link box)

Ignition switch

Starter relay [within the intelligent power distribution module engine room (IPDM E/R)]

Harness for open or short
2. CHECK “1” TERMINAL CONNECTION QUALITY (VOLTAGE DROP TEST)
1. Turn the ignition switch OFF.
2. Connect starter motor connector F28.
3. Check voltage between starter motor connector F28 terminal 1
(W/R) and battery positive terminal using a digital circuit tester.
OK or NG
OK >> Starter motor “1” terminal circuit is OK. Further inspec-
tion is necessary. Refer to SC-13, "
WORK FLOW" .
NG >> Check harness between the battery and the starter
motor “1” terminal for poor continuity. Ignition switch in
START.: Battery voltage
WKIA2108E
Ignition switch in
START.: Less than 1V
WKIA1792E

CHARGING SYSTEM
SC-19
C
D
E
F
G
H
I
J
L
MA
B
SC
Revision: August 20072004 QX56
Trouble Diagnoses with Battery/Starting/Charging System TesterEKS0079G
NOTE:
To ensure a complete and thorough diagnosis, the battery, starter and generator test segments must be done
as a set from start to finish.
1. Turn off all loads on the vehicle electrical system.
2. Perform battery and starting system test with Battery/Starting/
Charging system tester.
3. Press “ENTER” to begin the charging system test.
4. Start engine.
5. Press “ENTER” until “LOADS OFF REV ENGINE 5 SEC” is dis-
played.
6. Raise and hold the engine speed at 1,500 to 2,000 rpm for about
5 seconds, then return the engine to idle.
Once the increase in engine rpm is detected, press “ENTER” to
continue.
NOTE:

If after 30 seconds an increase in engine idle speed is not
detected, “RPM NOT DETECTED” will display.

Some engines may have a higher idle initially after starting,
particularly when the engine is cold. The tester may detect
this without any other action being taken. If this occurs, con-
tinue on with the testing process. The final results will not be affected.
7. The tester now checks the engine at idle and performs the
DIODE/RIPPLE check.
8. When complete, the tester will prompt you to turn on the follow-
ing electrical loads.

Heater fan set to highest speed. Do not run the A/C or wind-
shield defroster.

Headlamp high beam

Rear window defogger
NOTE:
Do not run the windshield wipers or any other cyclical loads.
9. Press “ENTER” to continue.
SEL417X
SEL418X
SEL419X
SEL420X

CHARGING SYSTEM
SC-23
C
D
E
F
G
H
I
J
L
MA
B
SC
Revision: August 20072004 QX56
DIAGNOSTIC PROCEDURE 2
Check Terminal "1" Circuit
1. CHECK “1” TERMINAL CONNECTION
1. Turn the ignition switch OFF.
2. Check to see if “1” terminal is clean and tight.
OK or NG
OK >> GO TO 2.
NG >> Repair “1” terminal connection. Confirm repair by performing complete Battery/Starting/Charging
system test.
2. CHECK GENERATOR “1” TERMINAL CIRCUIT
Check voltage between generator connector E206 terminal 1 (B/R)
and ground using a digital circuit tester.
OK or NG
OK >> GO TO 3.
NG >> Check the following.

140A fusible link (letter a , located in fusible link box)

Harness for open or short between generator and fus-
ible link
3. CHECK “1” TERMINAL CONNECTION QUALITY (VOLTAGE DROP TEST)
Check voltage between generator connector E206 terminal 1 (B/R)
and battery positive terminal using a digital circuit tester.
OK or NG
OK >> Replace the generator. Refer to SC-27, "Removal and
Installation" . Confirm repair by performing complete
Battery/Starting/Charging system test.
NG >> Check harness between the battery and the generator
for poor continuity.
DIAGNOSTIC PROCEDURE 3
Check Terminal "3" Circuit
1. CHECK “3” TERMINAL CONNECTION
1. Turn the ignition switch OFF.
2. Check to see if “3” terminal is clean and tight.
OK or NG
OK >> GO TO 2.
NG >> Repair “3” terminal connection. Confirm repair by performing complete Battery/Starting/Charging
system test. Battery voltage should exist.
W K I A 2111 E
With engine running
at idle and warm.: Less than 0.2V
WKIA2112E