INFINITI QX56 2004 Factory Service Manual

SC-10
STARTING SYSTEM
Revision: August 20072004 QX56
STARTING SYSTEMPFP:23300
System DescriptionEKS00798
Power is supplied at all times:

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

to ignition switch terminal B.
With the ignition switch in the START position, power is supplied:

from ignition switch terminal ST

to IPDM E/R terminal 21.
With the ignition switch in the ON or START position, power is supplied to IPDM E/R (intelligent power distribu-
tion module engine room) CPU.
With the selector lever in the P or N position, power is supplied:

through A/T assembly terminal 9

to IPDM E/R terminal 48.
Ground is supplied at all times:

to IPDM E/R terminals 38 and 59

from body grounds E9, E15 and E24.
Then the starter relay is turned on.
The IPDM E/R is energized and power is supplied:

from terminal 19 of the IPDM E/R

to terminal 1 of the starter motor windings.
The starter motor plunger closes and provides a closed circuit between the battery and the starter motor. The
starter motor is grounded to the cylinder block. With power and ground supplied, the starter motor operates.

STARTING SYSTEM
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Revision: August 20072004 QX56
Wiring Diagram — START —EKS00799
WKWA1150E

SC-12
STARTING SYSTEM
Revision: August 20072004 QX56
Trouble Diagnoses with Battery/Starting/Charging System TesterEKS0079A
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 test with Battery/Starting/Charging system
tester. Refer to SC-12, "
Trouble Diagnoses 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 SC-12,
"DIAGNOSTIC 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 OPERA-
TION” incidents, refer to SC-15, "
DIAGNOSTIC PROCE-
DURE 2" .
DIAGNOSTIC RESULT ITEM CHART
SEL408X
SEL409X
SEL410X
Diagnostic item Service procedure
CRANKING VOLTAGE NORMAL Go to SC-13, "
WORK FLOW" .
CRANKING VOLTAGE LOW Go to SC-13, "
WORK FLOW" .
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-12, "
Trouble
Diagnoses 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-12, "
Trouble Diagnoses
with Battery/Starting/Charging System Tester" . If second test result is “REPLACE BAT-
TERY”, then do so. Perform battery test again to confirm repair.

STARTING SYSTEM
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Revision: August 20072004 QX56
WORK FLOW
*1SC-12*2SC-14*3SC-15
*4SC-15
WKIA2104E

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
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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

SC-16
STARTING SYSTEM
Revision: August 20072004 QX56
MINIMUM SPECIFICATION OF CRANKING VOLTAGE REFERENCING COOLANT TEMPERA-
TURE
Removal and InstallationEKS0079B
REMOVAL
1. Remove the intake manifold. Refer to EM-15, "Removal and Installation" .
2. 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 "2" nut carefully.
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 "2"nut : 10.8 N·m (1.1 kg-m, 8 ft-lb)

CHARGING SYSTEM
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Revision: August 20072004 QX56
CHARGING SYSTEMPFP:23100
System DescriptionEKS0079E
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 4 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 4 detecting the input voltage. The charging circuit is protected by the
140A fusible link (letter a , located in the fusible link box).
Ground is supplied:

to generator terminal 2

through body ground E203.
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 3 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 warning lamp illuminates with the engine running, a fault is indicated.

SC-18
CHARGING SYSTEM
Revision: August 20072004 QX56
Wiring Diagram — CHARGE —EKS0079F
WKWA3103E

CHARGING SYSTEM
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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