2001 INFINITI QX4 Battery terminal

Control Unit
DIAGNOSTIC PROCEDURE=NBBR0106Malfunction code No. 71
1 INSPECTION START
ABS actuator and electric unit power supply and ground circuit inspection
SBR497E
©GO TO 2.
2 CHECK CONNECTOR
1. Disconnect ABS actuator and electric unit connector.
Check terminals for damage or loose connection. Then reconnect connector.
2. Carry out self-diagnosis again.
Does warning lamp activate again?
Ye s©GO TO 3.
No©INSPECTION END
3 CHECK ABS ACTUATOR AND ELECTRIC UNIT POWER SUPPLY CIRCUIT
Check voltage. Refer to ª5. CHECK ABS ACTUATOR AND ELECTRIC UNIT POWER SUPPLY CIRCUITº in ªDIAGNOS-
TIC PROCEDUREº, ªLow Voltageº, BR-63.
Does battery voltage exist when ignition switch is turned ON?
Ye s©GO TO 4.
No©Repair.
4 CHECK WARNING LAMP INDICATION
Does warning lamp indicate code No. 71 again?
YesorNo
Ye s©Replace ABS actuator and electric unit.
No©Inspect the system according to the code No.
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
Control Unit
BR-68

5 CHECK ABS ACTUATOR AND ELECTRIC UNIT POWER SUPPLY CIRCUIT
1. Disconnect ABS actuator and electric unit connector.
2. Check voltage between ABS actuator and electric unit connector E111 (body side) terminal 15 and ground.
SBR495E
Does battery voltage exist when ignition switch is turned ON?
Ye s©GO TO 6.
No©Check the following.
If NG, repair harness or connector.
IHarness connector E111
IHarness for open or short between ABS actuator and electric unit and fuse
6 CHECK WARNING LAMP
1. Disconnect ABS actuator and electric unit connector.
2. Connect suitable wire between ABS actuator and electric unit connector E111 (body side) terminal 10 (2WD) or 21
(4WD) and ground.
SBR502E
Does the warning lamp deactivate?
Ye s©Replace ABS actuator and electric unit.
No©GO TO 7.
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TROUBLE DIAGNOSES FOR SYMPTOMSABS
7. Warning Lamp Stays On When Ignition Switch Is Turned On (Cont'd)
BR-75

7 CHECK ABS WARNING LAMP CONTROL CIRCUIT FOR OPEN
1. Disconnect combination meter connector M24.
2. Check continuity between combination meter connector M24 (body side) terminal 10 and ABS actuator and electric unit
connector E111 (body side) terminal 10 (2WD) or 21 (4WD).
NOTE:
Connect positive lead of multimeter to combination meter connector M24 (body side) terminal 10 and negative lead to
ABS actuator and electric unit connector E111 (body side) terminal 10 (2WD) or 21 (4WD).
SBR675E
Continuity should exist.
Does continuity exist?
Ye s©Check combination meter.
Refer to EL-114, ªWARNING LAMPSº.
No©Repair harness or connectors.
8 REPLACE FUSE
Replace fuse.
Does the fuse blow out when ignition switch is turned ON?
Ye s©GO TO 9.
No©INSPECTION END
9 CHECK ABS ACTUATOR AND ELECTRIC UNIT POWER SUPPLY CIRCUIT FOR SHORT
1. Disconnect battery cable and ABS actuator and electric unit connector.
2. Check continuity between ABS actuator and electric unit connector E111 (body side) terminal 15 and ground.
SBR496E
Continuity should not exist.
Does continuity exist?
Ye s©Check the following.
If NG, repair harness or connector.
IHarness connector E111
IHarness for open or short between ABS actuator and electric unit and fuse
No©Replace ABS actuator and electric unit.
TROUBLE DIAGNOSES FOR SYMPTOMSABS
7. Warning Lamp Stays On When Ignition Switch Is Turned On (Cont'd)
BR-76

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBEC0002The Supplemental Restraint System such as ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº used along with
a seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain types of
collision. The SRS system composition which is available to INFINITI QX4 is as follows:
IFor a frontal collision
The Supplemental Restraint System consists of driver air bag module (located in the center of the steer-
ing wheel), front passenger air bag module (located on the instrument panel on passenger side), seat belt
pre-tensioners, a diagnosis sensor unit, warning lamp, wiring harness and spiral cable.
IFor a side collision
The Supplemental Restraint System consists of front side air bag module (located in the outer side of front
seat), satellite sensor, diagnosis sensor unit (one of components of air bags for a frontal collision), wiring
harness, warning lamp (one of components of air bags for a frontal collision).
Information necessary to service the system safely is included in theRS sectionof this Service Manual.
WARNING:
ITo avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be performed
by an authorized INFINITI dealer.
IImproper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the RS section.
IDo not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. Spiral cable and wiring harnesses covered with yellow insulation tape either just
before the harness connectors or for the complete harness are related to the SRS.
Precautions for On Board Diagnostic (OBD)
System of Engine and A/T
NBEC0003The ECM has an on board diagnostic system. It will light up the malfunction indicator lamp (MIL) to warn the
driver of a malfunction causing emission deterioration.
CAUTION:
IBe sure to turn the ignition switch OFF and disconnect the negative battery terminal before any
repair or inspection work. The open/short circuit of related switches, sensors, solenoid valves, etc.
will cause the MIL to light up.
IBe sure to connect and lock the connectors securely after work. A loose (unlocked) connector will
cause the MIL to light up due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)
ICertain systems and components, especially those related to OBD, may use a new style slide-
locking type harness connector. For description and how to disconnect, refer to EL-6, ªHARNESS
CONNECTOR (SLIDE-LOCKING TYPE)º.
IBe sure to route and secure the harnesses properly after work. The interference of the harness with
a bracket, etc. may cause the MIL to light up due to the short circuit.
IBe sure to connect rubber tubes properly after work. A misconnected or disconnected rubber tube
may cause the MIL to light up due to the malfunction of the fuel injection system, etc.
IBe sure to erase the unnecessary malfunction information (repairs completed) from the ECM and
TCM (Transmission control module) before returning the vehicle to the customer.
PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
EC-14

SEF289H
PrecautionsNBEC0005IBefore connecting or disconnecting the ECM harness
connector, turn ignition switch OFF and disconnect nega-
tive battery terminal. Failure to do so may damage the
ECM because battery voltage is applied to ECM even if
ignition switch is turned off.
SEF908W
IWhen connecting ECM harness connector, fasten it
securely with a lever as far as it will go as shown at left.
SEF291H
IWhen connecting or disconnecting pin connectors into or
from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM
pin terminal, when connecting pin connectors.
MEF040D
IBefore replacing ECM, perform ªECM Terminals and Ref-
erence Valueº inspection and make sure ECM functions
properly. Refer to EC-127.
SEF217U
IAfter performing each TROUBLE DIAGNOSIS, perform
ªDTC Confirmation Procedureº or ªOverall Function
Checkº.
The DTC should not be displayed in the ªDTC Confirma-
tion Procedureº if the repair is completed. The ªOverall
Function Checkº should be a good result if the repair is
completed.
PRECAUTIONS
Precautions
EC-16

SEF462UA
SEF598U
Without CONSULT-IINBEC0019S08021) Attach the EVAP service port adapter securely to the EVAP
service port.
2) Also attach the pressure pump with pressure gauge to the
EVAP service port adapter.
3) Apply battery voltage to between the terminals of both EVAP
canister vent control valve and vacuum cut valve bypass valve
to make a closed EVAP system.
4) To locate the leak, deliver positive pressure to the EVAP sys-
tem until pressure gauge points reach 1.38 to 2.76 kPa (0.014
to 0.028 kg/cm
2, 0.2 to 0.4 psi).
5) Remove EVAP service port adapter and hose with pressure
pump.
6) Locate the leak using a leak detector. Refer to ªEVAPORATIVE
EMISSION LINE DRAWINGº, EC-36.
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ENGINE AND EMISSION BASIC CONTROL SYSTEM DESCRIPTION
Evaporative Emission System (Cont'd)
EC-35

25 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1) SIGNAL
With CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (bank 1).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. See ªHO2S1 MNTR (B1)º in ªDATA MONITORº mode.
6. Maintaining engine at 2,000 rpm under no-load (engine is warmed up to normal operating temperature.), check that the
monitor fluctuates between ªLEANº and ªRICHº more than 5 times during 10 seconds.
1 time: RICH®LEAN®RICH
2 times: RICH®LEAN®RICH®LEAN®RICH
Without CONSULT-II
1. Stop engine.
2. Replace heated oxygen sensor 1 (front) (bank 1).
3. Start engine and warm it up to normal operating temperature.
4. Run engine at approx. 2,000 rpm for approx. 2 minutes under no-load.
5. Set voltmeter probe between ECM terminal 63 and ground.
6. Make sure that the voltage fluctuates between 0 - 0.3V and 0.6 - 1.0V more than 5 times during 10 seconds at 2,000
rpm.
1 time: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V
2 times: 0 - 0.3V®0.6 - 1.0V®0 - 0.3V®0.6 - 1.0V®0 - 0.3V
OK or NG
OK©INSPECTION END
NG©GO TO 26.
26 DETECT MALFUNCTIONING PART
Check the following.
ICheck fuel pressure regulator. Refer to EC-40.
ICheck mass air flow sensor and its circuit. Refer to EC-150.
ICheck injector and its circuit. Refer to EC-616.
Clean or replace if necessary.
ICheck engine coolant temperature sensor and its circuit. Refer to EC-187.
ICheck ECM function by substituting another known-good ECM.
(ECM may be the cause of a problem, but this is rarely the case.)
©GO TO 3.
27 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 1) HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect heated oxygen sensor 1 (front) (bank 1) harness connector.
4. Check harness continuity between ECM terminal 63 and heated oxygen sensor 1 (front) RH harness connector terminal
1.
Refer to Wiring Diagram, EC-196.
Continuity should exist.
OK or NG
OK©GO TO 30.
NG©GO TO 29.
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BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-53

28 CHECK HEATED OXYGEN SENSOR 1 (FRONT) (BANK 2) HARNESS
1. Turn off engine and disconnect battery ground cable.
2. Disconnect ECM harness connector.
3. Disconnect heated oxygen sensor 1 (front) (bank 2) harness connector.
4. Check harness continuity between ECM terminal 62 and front heated oxygen sensor LH harness connector terminal 1.
Refer to Wiring Diagram, EC-197.
Continuity should exist.
OK or NG
OK©GO TO 30.
NG©GO TO 29.
29 REPAIR OR REPLACE
Repair or replace harness between ECM and heated oxygen sensor 1 (front).
©GO TO 3.
30 PREPARATION FOR ªCOº % CHECK
With CONSULT-II
1. Reconnect ECM harness connector.
2. Turn ignition switch ªONº.
3. Select ªENG COOLANT TEMPº in ªACTIVE TESTº mode.
4. Set ªENG COOLANT TEMPº to 5ÉC (41ÉF) by touching ªDOWNº and ªQdº.
SEF172Y
Without CONSULT-II
1. Disconnect ECM harness connector.
2. Disconnect engine coolant temperature sensor harness connector.
3. Connect a resistor (4.4 kW) between terminals of engine coolant temperature sensor harness connector.
SEF982UA
©GO TO 31.
BASIC SERVICE PROCEDURE
Idle Speed/Ignition Timing/Idle Mixture Ratio Adjustment (Cont'd)
EC-54