INFINITI QX4 2001 Factory Service Manual

System DescriptionNBSC0004Power is supplied at all times
Ito ignition switch terminal 1
Ithrough 40A fusible link (lettere, located in the fuse and fusible link box).
With the ignition switch in the ON or START position, power is supplied through 10A fuse [No. 18, located in
the fuse block (J/B)].
Ito park/neutral position relay terminal 1.
Also, with the ignition switch in the START position, power is supplied
Ifrom ignition switch terminal 5
Ito park/neutral position relay terminal 6.
With the selector lever in the P or N position, ground is supplied
Ito park/neutral position relay terminal 2 through the park/neutral position switch.
Then park/neutral position relay is energized and power is supplied
Ifrom park/neutral position relay terminal 7
Ito terminal 2 of the starter motor windings.
The starter motor plunger closes and provides a closed circuit between the battery and starter motor. The
starter motor is grounded to the engine block. With power and ground supplied, cranking occurs and the engine
starts.
STARTING SYSTEM
System Description
SC-10

Wiring Diagram Ð START ÐNBSC0005
MEL652L
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
EL
IDX
STARTING SYSTEM
Wiring Diagram Ð START Ð
SC-11

Trouble Diagnoses with
Battery/Starting/Charging System Tester
NBSC0019NOTE:
To ensure a complete and thorough diagnosis, the battery, starter
and alternator test segments must be done as a set from start to
finish.
SEL408X
1. Turn off all loads on the vehicle electrical system.
2. Perform battery test with Battery/Starting/Charging system
tester. Refer to SC-7.
3. Press ªENTERº to begin the starting system test.
SEL409X
4. Start the engine.
SEL410X
5. Diagnosis result is displayed on the tester. Refer to ªDIAG-
NOSTIC RESULT ITEM CHARTº, SC-13.
NOTE:
IIf the starter performs normally but the engine does not start,
perform engine diagnosis.
IFor intermittent ªNO CRANKº or ªNO STARTER OPERATIONº
incidents, go to DIAGNOSTIC PROCEDURE 2.
STARTING SYSTEM
Trouble Diagnoses with Battery/Starting/Charging System Tester
SC-12

DIAGNOSTIC RESULT ITEM CHARTNBSC0019S01
Diagnostic item Service procedure
CRANKING VOLTAGE NORMAL Go to ªWORK FLOWº, SC-14.
CRANKING VOLTAGE LOW Go to ªWORK FLOWº, SC-14.
CHARGE BATTERYPerform the slow battery charging procedure. (Initial rate of charge is 10A for 12 hours.)
Perform battery test again with Battery/Starting/Charging system tester. Refer to SC-7.
REPLACE BATTERYBefore replacing battery, clean the battery cable clamps and battery posts. Perform bat-
tery test again with Battery/Starting/Charging system tester. Refer to SC-7. If second test
result is ªREPLACE BATTERYº, then do so. Perform battery test again to confirm repair.GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
EL
IDX
STARTING SYSTEM
Trouble Diagnoses with Battery/Starting/Charging System Tester (Cont'd)
SC-13

WORK FLOWNBSC0019S02
SEL411X
*1 SC-7
*2 SC-17*3 SC-15 *4 SC-17
STARTING SYSTEM
Trouble Diagnoses with Battery/Starting/Charging System Tester (Cont'd)
SC-14

DIAGNOSTIC PROCEDURE 1NBSC0019S03Check ªBº Terminal CircuitNBSC0019S0301
1 CHECK POWER SUPPLY FOR STARTER MOTOR ªBº 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 OFF.
4. Check that the starter motor terminal 1 connection is clean and tight.
5. Check voltage between starter motor terminal 1 and ground using a digital circuit tester.
SEL412X
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)
1. Check voltage between starter motor terminal 1 and battery positive terminal using a digital circuit tester.
SEL413X
OK or NG
OK©GO TO 3.
NG©Check harness between the battery and the starter motor for poor continuity.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
EL
IDX
STARTING SYSTEM
Trouble Diagnoses with Battery/Starting/Charging System Tester (Cont'd)
SC-15

3 CHECK STARTER MOTOR GROUND CIRCUIT (VOLTAGE DROP TEST)
1. Check voltage between starter motor case and battery negative terminal using a digital circuit tester.
SEL414X
OK or NG
OK©Starter motor ªBº terminal circuit is OK. Further inspection necessary. Refer to ªWORK
FLOWº, SC-14.
NG©Check the starter motor case and ground for poor continuity.
STARTING SYSTEM
Trouble Diagnoses with Battery/Starting/Charging System Tester (Cont'd)
SC-16

DIAGNOSTIC PROCEDURE 2=NBSC0019S04Check ªSº Terminal CircuitNBSC0019S0401
1 CHECK POWER SUPPLY FOR STARTER MOTOR ªSº 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 OFF.
4. Disconnect starter motor terminal 2 connector.
5. Check voltage between starter motor terminal 2 and ground using a digital circuit tester.
SEL415X
OK or NG
OK©GO TO 2.
NG©Check the following.
I40A fusible link (lettere, located in fuse and fusible link box)
IPark/neutral position relay
IHarness for open or short
2 CHECK ªSº TERMINAL CONNECTION QUALITY (VOLTAGE DROP TEST)
1. Connect starter motor terminal 2 connector.
2. Check voltage between starter motor terminal 2 and battery positive terminal using a digital tester.
SEL416X
OK or NG
OK©Starter motor ªSº terminal circuit is OK. Further inspection necessary. Refer to ªWORK
FLOWº, SC-14.
NG©Check harness between the battery and the starter motor ªSº terminal for poor continuity.
MINIMUM SPECIFICATION OF CRANKING VOLTAGE
REFERENCING COOLANT TEMPERATURE
NBSC0019S05
Engine coolant temperature Voltage V
þ30ÉC to þ20ÉC (þ22ÉF to þ4ÉF) 8.6
þ19ÉC to þ10ÉC (þ2ÉF to 14ÉF) 9.1
þ9ÉC to 0ÉC (16ÉF to 32ÉF) 9.5
More than 1ÉC (More than 34ÉF) 9.9
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
EL
IDX
STARTING SYSTEM
Trouble Diagnoses with Battery/Starting/Charging System Tester (Cont'd)
SC-17

ConstructionNBSC0006
MEL949LB
MEL950L
Removal and InstallationNBSC0007
Pinion/Clutch CheckNBSC00081. Inspect pinion teeth.
IReplace pinion if teeth are worn or damaged. (Also check
condition of ring gear teeth.)
2. Inspect reduction gear teeth.
IReplace reduction gear if teeth are worn or damaged. (Also
check condition of armature shaft gear teeth.)
3. Check to see if pinion locks in one direction and rotates
smoothly in the opposite direction.
IIf it locks or rotates in both directions, or unusual resistance is
evident, replace.
STARTING SYSTEM
Construction
SC-18

System DescriptionNBSC0009The alternator 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 alternator terminal S through:
I120A fusible link (lettera, located in the fuse and fusible link box), and
I7.5A fuse (No. 65, located in the fuse and fusible link box).
Terminal B supplies power to charge the battery and operate the vehicle's electrical system. Output voltage
is controlled by the IC regulator at terminal S detecting the input voltage. The charging circuit is protected by
the 120A fusible link.
Terminal E of the alternator supplies ground through body ground E101.
With the ignition switch in the ON or START position, power is supplied
Ithrough 10A fuse [No. 8, located in the fuse block (J/B)]
Ito combination meter terminal 12 for the charge warning lamp.
Ground is supplied to terminal 43 of the combination meter through terminal L of the alternator. With power
and ground supplied, the charge warning lamp will illuminate. When the alternator 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.GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
EL
IDX
CHARGING SYSTEM
System Description
SC-19