2011 INFINITI QX56 ignition

STC-18
< DTC/CIRCUIT DIAGNOSIS >
ENGINE SPEED SIGNAL CIRCUIT
ENGINE SPEED SIGNAL CIRCUIT
Diagnosis ProcedureINFOID:0000000006256129
1.PERFORM ECM SELF-DIAGNOSIS
With CONSULT-III
Perform “ENGINE” self-diagnosis.
Is any DTC detected?
YES >> Check the DTC. Refer to EC-98, "DTC Index".
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN ECM AND POWER STEERING CONTROL UNIT
1. Turn the ignition switch OFF.
2. Disconnect ECM harness connectors.
3. Disconnect power steering control unit harness connector.
4. Check the continuity between ECM harness connecto r and power steering control unit harness connector.
5. Check the continuity between power st eering control unit harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace error-detected parts.
3.CHECK ENGINE SPEED SIGNAL (ECM)
1. Connect ECM harness connectors.
2. Check the signal between ECM harness connector and ground with oscilloscope.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace ECM. Refer to EC-143, "
Description".
ECM Power steering control unit
Continuity
Connector Terminal Connector Terminal
E80 169 M108 10 Existed
Power steering control unit — Continuity
Connector Terminal
M108 10 Ground Not existed
ECM — Condition Voltage (Approx.)
Connector Terminal
E80 169 Ground Engine is running
 Warm-up condition
 Idle speed
Engine is running
 Warm-up condition
 Engine speed: Approx. 2,000 rpm
JPBIA3352ZZ
JPBIA3354ZZ
Revision: 2010 May2011 QX56

ENGINE SPEED SIGNAL CIRCUITSTC-19
< DTC/CIRCUIT DIAGNOSIS >
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4.CHECK ENGINE SPEED SIGNAL (P OWER STEERING CONTROL UNIT)
1. Turn the ignition switch OFF.
2. Connect power steering control unit harness connector.
3. Check the signal between power steering control unit harness connector and ground with oscilloscope.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Replace power steering control unit. Refer to STC-23, "
Removal and Installation".
5.CHECK TERMINALS AND HARNESS CONNECTORS
 Check the power steering control unit pin terminal s for damage or loose connection with harness connector.
 Check the ECM pin terminals for damage or loose connection with harness connector.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Repair or replace error-detected parts.
Power steering control unit — Condition Voltage (Approx.)
Connector Terminal
M108 10 Ground Engine is running
 Warm-up condition
 Idle speed
Engine is running
 Warm-up condition
 Engine speed: Approx. 2,000 rpm
JPBIA3352ZZ
JPBIA3354ZZ
Revision: 2010 May2011 QX56

STC-20
< DTC/CIRCUIT DIAGNOSIS >
VEHICLE SPEED SIGNAL CIRCUIT
VEHICLE SPEED SIGNAL CIRCUIT
Diagnosis ProcedureINFOID:0000000006256130
1.PERFORM COMBINATION METER SELF-DIAGNOSIS
With CONSULT-III
Perform “METER/M&A” self-diagnosis. Refer to MWI-30, "
CONSULT-III Function".
Is any DTC detected?
YES >> Check the DTC.
NO >> GO TO 2.
2.CHECK HARNESS BETWEEN COMBINATION ME TER AND POWER STEERING CONTROL UNIT
1. Turn the ignition switch OFF.
2. Disconnect combination meter harness connector.
3. Disconnect power steering control unit harness connector.
4. Check the continuity between combination meter harness connector and power steering control unit har-
ness connector.
5. Check the continuity between power st eering control unit harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace error-detected parts.
3.CHECK VEHICLE SPEED SIGN AL (COMBINATION METER)
1. Connect combination meter harness connector.
2. Check the combination meter input/output standard values. Refer to MWI-35, "
Reference Value".
Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace combination meter Refer to MWI-85, "
Removal and Installation".
4.CHECK VEHICLE SPEED SIGNAL (POWER STEERING CONTROL UNIT)
1. Turn the ignition switch OFF.
2. Connect power steering control unit harness connector.
3. Check the signal between power steering cont rol unit harness connector and ground with oscilloscope.
Combination meter Power steering control unit
Continuity
Connector Terminal Connector Terminal
M34 30 M108 8 Existed
Power steering control unit —Continuity
Connector Terminal
M108 8 Ground Not existed
Power steering control unit — Condition Voltage (Approx.)
Connector Terminal
M108 8 Ground Vehicle speed: 40 km/h (25 MPH)
CAUTION:
Check air pressure of tire under
standard condition.NOTE:
The maximum voltage varies de-
pending on the specification (desti-
nation unit).
JSNIA0015GB
Revision: 2010 May2011 QX56

STR-2
< PRECAUTION >
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint System (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006275515
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the “SRS AIR BAG” and “SEAT BELT” of this
Service Manual.
WARNING:
• To avoid rendering the SRS inopera tive, which could increase the risk of personal injury or death in
the event of a collision that would result in air bag inflation, all maintenance must be performed by
an authorized NISS AN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.
 Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
 When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the ignition ON or engine running, DO NOT use air or electric power tools or strike near the sensor(s)
with a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly
causing serious injury.
 When using air or electric power tools or hammers , always switch the ignition OFF, disconnect the
battery, and wait at least 3 minu tes before performing any service.
Precaution Necessary for Steering W heel Rotation after Battery Disconnect
INFOID:0000000006275516
NOTE:
 Before removing and installing any control units, first tu rn the push-button ignition switch to the LOCK posi-
tion, then disconnect bot h battery cables.
 After finishing work, confirm that all control unit connectors are connected properly, then re-connect both
battery cables.
 Always use CONSULT-III to perform self-diagnosis as a part of each function inspection after finishing work.
If a DTC is detected, perform trouble diagnos is according to self-diagnosis results.
For vehicle with steering lock unit, if the battery is disconnected or discharged, the steering wheel will lock and
cannot be turned.
If turning the steering wheel is required with the bat tery disconnected or discharged, follow the operation pro-
cedure below before starting the repair operation.
OPERATION PROCEDURE
1. Connect both battery cables. NOTE:
Supply power using jumper cables if battery is discharged.
2. Turn the push-button ignition switch to ACC position. (At this time, the steering lock will be released.)
3. Disconnect both battery cables. The steering lock wi ll remain released with both battery cables discon-
nected and the steering wheel can be turned.
4. Perform the necessary repair operation.
Revision: 2010 May2011 QX56

PRECAUTIONSSTR-3
< PRECAUTION >
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5. When the repair work is completed, re-connect both
battery cables. With the brake pedal released, turn
the push-button ignition switch from ACC position to ON position, then to LOCK position. (The steering
wheel will lock when the push-button ignition switch is turned to LOCK position.)
6. Perform self-diagnosis check of a ll control units using CONSULT-III.
Revision: 2010 May2011 QX56

STR-14
< DTC/CIRCUIT DIAGNOSIS >
B TERMINAL CIRCUIT
DTC/CIRCUIT DIAGNOSIS
B TERMINAL CIRCUIT
Diagnosis ProcedureINFOID:0000000006275524
CAUTION:
Perform diagnosis under the condition 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 “B” TERMINAL CIRCUIT
1. Turn ignition switch OFF.
2. Check that starter motor “B” terminal connection is clean and tight.
3. Check voltage between starter motor “B” terminal and ground.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Check harness between battery and starter motor for open circuit.
2.CHECK BATTERY CABLE CONNECTION STATUS (VOLTAGE DROP TEST)
1. Shift A/T selector lever to “P” or “N” position.
2. Check voltage between battery positive terminal and starter motor “B” terminal.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Check harness between the battery and the starter motor for poor continuity.
3.CHECK GROUND CIRCUIT STATUS (VOLTAGE DROP TEST)
1. Shift A/T selector lever to “P” or “N” position.
2. Check voltage between starter motor case and battery negative terminal.
Is the inspection result normal?
YES >> “B” terminal circuit is OK. Further inspection is necessary. Refer to STR-11, "Work Flow".
NO >> Check the starter motor case and ground for poor continuity.
(+) (–) Voltage
Starter motor “B” terminal
F57 2 Ground Battery voltage
(+) (–)
ConditionVoltage (V)
(Approx.)
Starter motor “B” terminal
Battery positive terminal F57 2 When the ignition switch
is in START position Less than 0.5
(+) (–) Condition Voltage (V)
(Approx.)
Starter motor case Battery negative terminal When the ignition switch is in START position Less than 0.2
Revision: 2010 May2011 QX56

S CONNECTOR CIRCUITSTR-15
< DTC/CIRCUIT DIAGNOSIS >
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S CONNECTOR CIRCUIT
Diagnosis ProcedureINFOID:0000000006275525
CAUTION:
Perform diagnosis under the cond
ition 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 “S” CONNECTOR CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect starter motor connector.
3. Shift A/T selector lever to “P” or “N” position.
4. Check voltage between starter motor harness connector and ground.
Is the inspection result normal?
YES >> “S” connector circuit is OK. Furt her inspection is necessary. Refer to STR-11, "Work Flow".
NO >> GO TO 2.
2.CHECK HARNESS CONTI NUITY (OPEN CIRCUIT)
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R harness connector.
3. Check continuity between starter motor harness connector and IPDM E/R harness connector.
Is the inspection result normal?
YES >> Further inspection is necessary. Refer to SEC-48, "Work Flow".
NO >> Repair the harness or connector.
(+)
(–) Condition Voltage
Starter motor
Connector Terminal
F55 1 Ground When the ignition switch
is in START position Battery voltage
Starter motor harness IPDM E/R
Continuity
Connector Terminal Connector Terminal
F55 1 E10 3 Existed
Revision: 2010 May2011 QX56

TM-6
< PRECAUTION >[7AT: RE7R01B]
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint S
ystem (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000006226734
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the “SRS AIR BAG” and “SEAT BELT” of this
Service Manual.
WARNING:
• To avoid rendering the SRS inopera tive, which could increase the risk of personal injury or death in
the event of a collision that would result in air bag inflation, all maintenance must be performed by
an authorized NISS AN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the “SRS AIR BAG”.
 Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
 When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the ignition ON or engine running, DO NOT use air or electric power tools or strike near the sensor(s)
with a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly
causing serious injury.
 When using air or electric power tools or hammers , always switch the ignition OFF, disconnect the
battery, and wait at least 3 minu tes before performing any service.
General PrecautionsINFOID:0000000006226735
Turn ignition switch OFF an d disconnect the battery cable
from the negative terminal before connecting or disconnect-
ing the A/T assembly connector. Because battery voltage is
applied to TCM even if igniti on switch is turned OFF.
 Perform “DTC (Diagnostic Trouble Code) CONFIRMATION
PROCEDURE” after performing each TROUBLE DIAGNOSIS.
If the repair is completed DTC should not be displayed in the
“DTC CONFIRMATION PROCEDURE”.
 Always use the specified brand of ATF. Refer to MA-10, "
Fluids
and Lubricants".
 Use lint-free paper not cloth rags during work.
 Dispose of the waste oil using the methods prescribed by law, ordi-
nance, etc. after replacing the ATF.
 Before proceeding with disassembly, thoroughly clean the outside of the transmission. It is important to prevent the internal parts from
becoming contaminated by dirt or other foreign matter.
SEF289H
SEF217U
Revision: 2010 May2011 QX56