INFINITI QX56 2010 Factory Service Manual

STR-6
< BASIC INSPECTION >
DIAGNOSIS AND REPAIR WORKFLOW
NOTE:
To ensure a complete and thorough diagnosis, the battery, starter motor and generator test segments must be
done as a set from start to finish.
1.DIAGNOSIS WITH MULTITASKING BATTERY DIAGNOSTIC STATION
Perform the starting system test with multitasking batte ry diagnostic station. For details and operating instruc-
tions, refer to diagnostic station instruction manual.
Te s t r e s u l t
CRANKING NORMAL>>GO TO 2.
LOW VOLTAGE>>GO TO 5.
CHARGE BATTERY>>Perform the slow battery charging procedure. (Initial rate of charge is 10A for 12
hours.) Perform battery test again. Refer to diagnostic station instruction manual.
REPLACE BATTERY>>Before replacing battery, clean t he battery cable clamps and battery posts. Perform
battery test again. Refer to diagnostic station instruction manual. If second test result is
“REPLACE BATTERY”, then do so. Perform battery test again to confirm repair.
2.CRANKING CHECK
Check that the starter motor operates properly.
Does the engine crank normally?
YES >> GO TO 3.
NO >> GO TO 4.
3.ENGINE START CHECK
Check that the engine starts.
Does the engine start?
YES >> Starter motor is OK. Inspection End.
NO >> Perform further diagnosis of engine mechanical or engine control system. Refer to EM and EC sections. Once resolved, perform battery test again.
4.STARTER MOTOR ACTIVATION
Check that the starter motor operates.
Does the starter motor turn?
YES >> Check ring gear and starter motor drive pinion. Once resolved, perform battery test again.
NO >> GO TO 7.
5.COMPARISON BETWEEN ENGINE COOLANT AND CRANKING VOLTAGE
Compare the engine coolant temperature and verify the cranking voltage is within specification.
Minimum Specification of Cranking Voltage Referencing Coolant Temperature
Is the voltage less than the specified value?
YES >> GO TO 7.
NO >> GO TO 6.
6.STARTER OPERATION
Check the starter operation.
Does the starter motor turn smoothly?
YES >> Starter motor is OK. Inspection End.
NO >> GO TO 7.
7.“B” TERMINAL CIRCUIT INSPECTION
Check “B” terminal circuit. Refer to STR-10, "
Diagnosis Procedure".
Is
“B” terminal circuit normal?
Engine coolant temperature [ °C ( °F)] Voltage [V]
− 30 to − 20 (−22 to − 4) 8.6
− 19 to −10 ( −2 to 14) 9.1
− 9 to 0 (16 to 32) 9.5
More than 1 (More than 34) 9.9
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DIAGNOSIS AND REPAIR WORKFLOWSTR-7
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YES >> GO TO 8.
NO >> Repair as needed.
8.“S” CONNECTOR CIRCUIT INSPECTION
Check “S” connector circuit. Refer to STR-12, "
Diagnosis Procedure".
Is
“S” connector circuit normal?
YES >> GO TO 9.
NO >> Repair as needed.
9.ENGINE ROTATION STATUS
Check that the engine can be rotated by hand.
Does the engine turn freely by hand?
YES >> Replace starter motor.
NO >> Perform further diagnosis of engine mechanical or powertrain mechanism. Refer to EM or TM
sections. Once resolved, perform battery test agai n. Refer to diagnostic station instruction man-
ual.
Revision: April 20092010 QX56

STR-8
< FUNCTION DIAGNOSIS >
STARTING SYSTEM
FUNCTION DIAGNOSIS
STARTING SYSTEM
System DiagramINFOID:0000000005149550
System DescriptionINFOID:0000000005149551
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.
Component Parts LocationINFOID:0000000005149552
ALBIA0416GB
1. A/T assembly F9 (with built in TCM
F502) 2. IPDM E/R E119, E120, E122, E124 3. BCM M18 (view with instrument panel
lower LH panel removed)
AWBIA0127ZZ
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STARTING SYSTEMSTR-9
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Component DescriptionINFOID:0000000005149553
Component part
Description
TCM TCM supplies power to the starter relay inside the IPDM E/R when
the selector lever is shifted to the P or N position.
BCM BCM sends a starter request signal to the CPU of the IPDM E/R
over the CAN communication lines.
IPDM E/R CPU inside IPDM E/R operates the starter relay at the request of
the BCM over the CAN communication lines.
Starter motor The starter motor plunger closes and the motor is supplied with
battery power, which in turn cranks the engine, when the “S” ter-
minal is supplied with electric power.
Revision: April 20092010 QX56

STR-10
< COMPONENT DIAGNOSIS >
B TERMINAL CIRCUIT
COMPONENT DIAGNOSIS
B TERMINAL CIRCUIT
DescriptionINFOID:0000000005149554
Terminal "2" (B) is constantly supplied with battery power.
Diagnosis ProcedureINFOID:0000000005149555
Regarding Wiring Diagram information, refer to STR-14, "Wiring Diagram".
CAUTION:
Perform diagnosis under the condi tion that the engine cannot start by the following procedure.
1. Remove fuel pump fuse.
2. Crank or start the engine (where possible) until the fuel pressure is depleted.
1.CHECK TERMINAL 2 POWER SUPPLY VOLTAGE
1. Turn ignition switch OFF.
2. Make sure that starter motor connector F27 terminal 2 connection is clean and tight.
3. Check voltage between starter motor connector F27 terminal 2
and ground.
Is there battery voltage present?
YES >> GO TO 2
NO >> Check harness between battery and starter motor for open circuit.
2.CHECK BATTERY CABLE (VOLTAGE DROP TEST)
1. Shift the transmission into park or neutral.
2. Check voltage between battery positive terminal and starter motor connector F27 terminal 2 while cranking the engine.
Is the voltage drop less than 0.2V?
YES >> GO TO 3
NO >> Check harness between the battery and the starter motor for high resistance.
3.CHECK GROUND CIRCUIT STATUS (VOLTAGE DROP TEST)
(+) (-)Condition Voltage
Connector Terminal
F27 2 Ground While cranking the
engine Battery voltage
AWBIA0122GB
(+)
(-)Condition Voltage
Connector Terminal
F27 2 Battery (+)
terminal While cranking the
engine Less than 0.2V
AWBIA0123GB
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B TERMINAL CIRCUITSTR-11
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Check voltage between starter motor case and battery negative ter-
minal while cranking the engine.
Is the voltage drop less than 0.2V?
YES >> Terminal 2 circuit is OK. Further inspection necessary.
Refer to STR-5, "
Work Flow".
NO >> Check the starter motor case to engine mounting for
high resistance.
(+) (-)Condition Voltage
Starter motor case Battery (-) terminal While cranking the
engine Less than 0.2V
AWBIA0124GB
Revision: April 20092010 QX56

STR-12
< COMPONENT DIAGNOSIS >
S CONNECTOR CIRCUIT
S CONNECTOR CIRCUIT
DescriptionINFOID:0000000005149556
Terminal "1" (S) is the power supply for the starter motor magnetic switch. Terminal 1 is supplied with power
when the ignition switch is turned to the START position while the selector lever is in the P or N position.
Diagnosis ProcedureINFOID:0000000005149557
Regarding Wiring Diagram information, refer to STR-14, "Wiring Diagram".
CAUTION:
Perform diagnosis under the condi tion that engine cannot start by the following procedure.
1. Remove fuel pump fuse.
2. Crank or start the engine (where possi ble) until the fuel pressure is released.
1.CHECK STARTER MOTOR MAGNETIC SWITCH CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect starter motor connector F28.
3. Shift transmission into park or neutral.
4. Check voltage between starter motor harness connector F28 terminal 1 and ground with the ignition in START.
Is battery voltage present?
YES >> Magnetic switch circuit is OK. Further inspection necessary. Refer to STR-5, "Work Flow".
NO >> GO TO 2
2.CHECK CONNECTOR
1. Turn ignition switch OFF.
2. Check the IPDM E/R harness connector E120 and st arter motor harness connector F28 for damage, bent
pins and loose connections.
Is the inspection result normal?
YES >> GO TO 3
NO >> Repair the terminal and connector.
3.CHECK HARNESS CONTI NUITY (OPEN CIRCUIT)
1. Disconnect IPDM E/R connector E120 and starter motor con- nector F28.
2. Check continuity between starter motor harness connector F28
(A) terminal 1 and IPDM E/R harness connector E120 (B) termi-
nal 19.
3. Check continuity between starter motor harness connector F28 (A) terminal 1 and ground.
(+) (-)Condition Voltage
Connector Terminal
F28 1 Ground Ignition in START Battery voltage
AWBIA0125GB
AB Continuity
Connector Terminal Connector Terminal
F28 1E120 19 Yes
A —Contin u it y
Connector Terminal
F28 1Ground No
AWBIA0126GB
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S CONNECTOR CIRCUITSTR-13
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Are the continuity test results as specified?
YES >> Further inspection necessary. Refer to
STR-5, "Work Flow".
NO >> Repair the harness.
Revision: April 20092010 QX56

STR-14
< COMPONENT DIAGNOSIS >
STARTING SYSTEM
STARTING SYSTEM
Wiring DiagramINFOID:0000000005149558
ABBWA0118GB
Revision: April 20092010 QX56

STARTING SYSTEMSTR-15
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ABBIA0387GB
Revision: April 20092010 QX56