2007 INFINITI QX56 engine

STARTING SYSTEM
SC-11
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
L
MA
B
SC
N
O
P
1. Turn off all loads on the vehicle electrical system.
2. Perform battery test with Battery/Starting/Charging system
tester. Refer to SC-6, "
Trouble Diagnosis with Battery/Starting/
Charging System Tester" .
3. Press “ENTER” to begin the starting system test.
4. Start the engine.
5. Diagnosis result is displayed on the tester. Refer to "DIAGNOS-
TIC RESULT ITEM CHART".
NOTE:
• If the starter performs normally but the engine does not start,
perform engine diagnosis.
• For intermittent “NO CRANK” or “NO STARTER OPERATION”
incidents, refer to "DIAGNOSTIC PROCEDURE 2" .
DIAGNOSTIC RESULT ITEM CHART
WORK FLOW
SEL408X
SEL409X
SEL410X
Diagnostic item Service procedure
CRANKING VOLTAGE NORMAL
Go to "WORK FLOW" .
CRANKING VOLTAGE LOW
CHARGE BATTERYPerform the slow battery charging procedure. (Initial rate of charge is 10A for 12 hours.) Per-
form battery test again with Battery/Starting/Charging system tester. Refer to SC-6, "
Trouble
Diagnosis with Battery/Starting/Charging System Tester" .
REPLACE BATTERYBefore replacing battery, clean the battery cable clamps and battery posts. Perform battery
test again with Battery/Starting/Charging system tester. Refer to SC-6, "
Trouble Diagnosis with
Battery/Starting/Charging System Tester" . If second test result is “REPLACE BATTERY”, then
do so. Perform battery test again to confirm repair.

SC-12
< SERVICE INFORMATION >
STARTING SYSTEM
DIAGNOSTIC PROCEDURE 1
Check Starter Motor Circuit
1.CHECK POWER SUPPLY TO STARTER MOTOR
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.
*1SC-6, "Trouble Diagnosis with Bat-
tery/Starting/Charging System
Te s t e r"
*2 "MINIMUM SPECIFICATION OF
CRANKING VOLTAGE REFERENC-
ING COOLANT TEMPERATURE"*3 "DIAGNOSTIC PROCEDURE 1"
*4 "DIAGNOSTIC PROCEDURE 2"
WKIA4532E

STARTING SYSTEM
SC-13
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
L
MA
B
SC
N
O
P
4. Check that the starter motor connector F27 connection is clean and tight.
5. Check voltage between starter motor connector F27 terminal 2
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 VOLTAGE DROP ON STARTER MOTOR CIRCUIT
Check voltage between starter motor connector F27 terminal 2 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 VOLTAGE DROP ON STARTER MOTOR GROUND CIRCUIT
Check voltage between starter motor case and battery negative ter-
minal using a digital circuit tester.
OK or NG
OK >> Starter motor ground circuit is OK. Further inspection is
necessary. Refer to "WORK FLOW" .
NG >> Check harness between the starter motor case and
ground for poor continuity.
DIAGNOSTIC PROCEDURE 2
Check Magnetic Switch Circuit
1.CHECK POWER SUPPLY FOR MAGNETIC SWITCH
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
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 Battery voltage should ex-
ist.
WKIA2105E
Ignition switch in
START.: Less than 0.5V
WKIA2106E
Ignition switch in
START.: Less than 0.2V
WKIA3437E
Ignition switch in
START.: Battery voltage
WKIA2108E

SC-14
< SERVICE INFORMATION >
STARTING SYSTEM
• Starter relay [within the intelligent power distribution module engine room (IPDM E/R)]
• Harness for open or short
2.CHECK VOLTAGE DROP ON MAGNETIC SWITCH CIRCUIT
1. Turn the ignition switch OFF.
2. Connect starter motor connector F28.
3. Check voltage between starter motor connector F28 terminal 1
and battery positive terminal using a digital circuit tester.
OK or NG
OK >> Magnetic switch circuit is OK. Further inspection is nec-
essary. Refer to "WORK FLOW" .
NG >> Check harness between the battery and the magnetic
switch for poor continuity.
MINIMUM SPECIFICATION OF CRANKING VOLTAGE REFERENCING COOLANT TEMPERA-
TURE
Removal and InstallationINFOID:0000000003533322
REMOVAL
1. Remove the intake manifold. Refer to EM-17, "Removal and Installation".
2. Remove/disconnect the starter harness connectors.
3. Remove the two starter bolts, using power tools.
4. Remove the starter.
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:
Tighten terminal nut carefully.Ignition switch in
START.: Less than 1V
WKIA1792E
Engine coolant temperature Voltage V
−30°C to −20°C (−22°F to −4°F) 8.4
−19°C to −10°C (−2°F to 14°F) 8.9
−9°C to 0°C (16°F to 32°F) 9.3
More than 1°C (More than 34°F) 9.7
WKIA1388E
Terminal nut : 10.8 N·m (1.1 kg-m, 8 ft-lb)

CHARGING SYSTEM
SC-15
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
L
MA
B
SC
N
O
P
CHARGING SYSTEM
System DescriptionINFOID:0000000003533323
The generator provides DC voltage to operate the vehicle's electrical system and to keep the battery charged.
The voltage output is controlled by the IC regulator.
Power is supplied at all times to generator terminal 3 through
• 10A fuse (No. 30, located in the fuse and fusible link box).
Terminal 1 supplies power to charge the battery and operate the vehicle's electrical system. Output voltage is
controlled by the IC regulator at terminal 3 detecting the input voltage. A pulse width modulated (PWM) signal
is sent from terminal 37 of the IPDM E/R to terminal 4 of the generator. The ECM determines the duty cycle of
the power generation variable voltage control system. The charging circuit is protected by the 140A fusible link
[letter a, located in the fusible link box (battery)].
The generator is grounded through the engine.
With the ignition switch in the ON or START position, power is supplied
• through 10A fuse [No. 14, located in the fuse block (J/B)]
• to combination meter terminal 24 for the charge warning lamp.
Ground is supplied to terminal 13 of the combination meter through terminal 2 of the generator. With power
and ground supplied, the charge warning lamp will illuminate. When the generator is providing sufficient volt-
age with the engine running, the ground is opened and the charge warning lamp will go off. If the charge warn-
ing lamp illuminates with the engine running, a fault is indicated. The IC regulator warning function activates to
illuminate “CHARGE” warning lamp, if any of the following symptoms occur while generator is operating:
• Excessive voltage is produced.
• No voltage is produced.
POWER GENERATION VARIABLE VOLTAGE CONTROL SYSTEM
NOTE:
Power generation variable voltage control system has been adopted. By varying the voltage to the generator,
engine load due to power generation of the generator is reduced and fuel consumption is decreased.
Operation
• The battery current sensor detects the charging/discharging current of the battery. ECM judges the battery
condition based on this signal.
• ECM judges whether to control voltage according to the battery condition.
• ECM calculates the target power generation voltage according to the battery condition and sends the calcu-
lated value, through CAN lines, as the power generation command value to IPDM E/R.
• IPDM E/R converts the received power generation command value into the power generation command sig-
nal (PWM signal) and sends it to the IC regulator.
• The IC regulator performs final control over the power generation voltage.
• When there is no power generation command signal, the generator performs the normal power generation
according to the characteristic of the IC regulator.
NOTE:
When any malfunction is detected in the power generation variable voltage control system, power generation
is performed according to the characteristic of the IC regulator in the generator.
PKIB4908E

SC-18
< SERVICE INFORMATION >
CHARGING SYSTEM
Before starting, perform the preliminary inspection. Refer to "PRELIMINARY INSPECTION".
1. Stop the operation of the power generation variable voltage control system using either of the following
procedures.
• Using the CONSULT-II, select "ENGINE" from "SELECT SYSTEM" and set the "ALT DUTY" to 0%.
Keep "ALT DUTY" at 0% until the end of the inspection. When the "ALT DUTY" value is 0% or 100%,
normal power generation is performed according to the characteristic of the IC regulator in the genera-
tor.
• Turn the ignition switch off, and disconnect the battery current sensor connector. Disconnecting the bat-
tery current sensor may cause DTC (P1550 - P1554) to set. After finishing the inspection, connect the
battery current sensor connector and erase the self-diagnostic results history of the engine using CON-
SULT-II.
2. Turn off all loads on the vehicle electrical system.
3. Perform battery and starting system test with Battery/Starting/
Charging system tester.
4. Press “ENTER” to begin the charging system test.
5. Start engine.
6. Press “ENTER” until “LOADS OFF REV ENGINE 5 SEC” is dis-
played.
7. 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, continue
on with the testing process. The final results will not be affected.
8. The tester now checks the engine at idle and performs the
DIODE/RIPPLE check.
9. 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.
SEL417X
SEL418X
SEL419X

CHARGING SYSTEM
SC-19
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
L
MA
B
SC
N
O
P
10. Press “ENTER” to continue.
11. 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 be displayed. Press
“ENTER” to restart the test.
12. Diagnostic result is displayed on the tester. Refer to "DIAGNOS-
TIC RESULT ITEM CHART".
13. Press “ENTER” then test output code is displayed. Record the
test output code on the repair order.
14. Toggle back to the “DIAGNOSTIC SCREEN” for test results.
DIAGNOSTIC RESULT ITEM CHART
SEL420X
SEL421X
SEL422X
SEL577X
Diagnostic item Service procedure
CHARGING SYSTEM NORMAL Charging system is normal and will also show DIODE RIPPLE test result.
NO CHARGING VOLTAGE
Go to "WORK FLOW". LOW CHARGING VOLTAGE
HIGH CHARGING VOLTAGE
DIODE RIPPLE NORMAL Diode ripple is OK and will also show CHARGING VOLTAGE test result.

SC-22
< SERVICE INFORMATION >
CHARGING SYSTEM
Check voltage between generator connector E204 terminal 1 and
ground using a digital circuit tester.
OK or NG
OK >> GO TO 3.
NG >> Check harness for open between generator and fusible
link.
3.CHECK VOLTAGE DROP ON BATTERY CIRCUIT
1. Start engine.
2. While engine is running at idle and warm, check voltage
between generator connector E204 terminal 1 and battery posi-
tive terminal using a digital circuit tester.
OK or NG
OK >> GO TO "WORK FLOW" .
NG >> Check harness between the battery and the generator
for poor continuity.
DIAGNOSTIC PROCEDURE 3
Check Voltage Regulator Circuit
1.CHECK VOLTAGE REGULATOR CIRCUIT CONNECTION
1. Turn the ignition switch OFF.
2. Check terminal 3 harness connector.
OK or NG
OK >> GO TO 2.
NG >> Repair terminal 3 connection. Confirm repair by performing complete Battery/Starting/Charging
system test. Refer to "Trouble Diagnoses with Battery/Starting/Charging System Tester" .
2.CHECK VOLTAGE REGULATOR CIRCUIT
Check voltage between generator connector E205 terminal 3 and
ground using a digital circuit tester.
OK or NG
OK >> GO TO "WORK FLOW".
NG >> Check harness for open between generator and fuse.
Removal and InstallationINFOID:0000000003533326
REMOVAL
1. Disconnect the negative battery terminal.
2. Remove the fan shroud. Refer to CO-13, "
Removal and Installation".
3. Remove the drive belt. Refer to EM-13, "
Removal and Installation". Battery voltage should exist.
WKIA2111E
With engine running
at idle and warm.: Less than 0.2V
WKIA3185E
Battery voltage should exist.
WKIA3186E