2001 INFINITI QX4 Ac system

PBR455D
DATA MONITOR PROCEDURENBBR0097S031. Turn ignition switch OFF.
2. Connect CONSULT-II to data link connector.
3. Turn ignition switch ON.
4. Touch ªSTARTº on CONSULT-II screen.
SBR670E
5. Touch ªABSº.
SBR636E
6. Touch ªDATA MONITORº.
SBR637E
7. Touch ªSETTINGº on ªSELECT MONITOR ITEMº screen.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONABS
CONSULT-II Inspection Procedure (Cont'd)
BR-46

PBR455D
ACTIVE TEST PROCEDURE=NBBR0097S04IWhen conducting Active test, vehicle must be stationary.
IWhen ABS warning lamp stays on, never conduct Active test.
1. Turn ignition switch OFF.
2. Connect CONSULT-II to data link connector.
3. Start engine.
4. Touch ªSTARTº on CONSULT-II screen.
SBR670E
5. Touch ªABSº.
SBR636E
6. Touch ªACTIVE TESTº.
SBR671E
7. Select active test item by touching screen.
SBR639E
8. Touch ªSTARTº.
9. Carry out the active test by touching screen key.
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONABS
CONSULT-II Inspection Procedure (Cont'd)
BR-47

DATA MONITOR MODENBBR0097S05
MONITOR ITEM CONDITION SPECIFICATION
FR RH SENSOR
FR LH SENSOR
RR RH SENSOR
RR LH SENSORDrive vehicle.
(Each wheel is rotating.)Wheel speed signal
(Almost the same speed as speedometer.)
STOP LAMP SW Brake is depressed.Depress the pedal: ON
Release the pedal: OFF
G-SWITCHHVehicle is driven.
Vehicle is stopped.
Brake is applied.During sudden braking while driving on high  roads (asphalt
roads, etc.): OFF
While vehicle is stopped or during constant-speed driving: ON
FR RH IN SOL
FR RH OUT SOL
FR LH IN SOL
FR LH OUT SOL
RR IN SOL
RR OUT SOL1. Drive vehicle at speeds
over 30 km/h (19 MPH) for at
least 1 minute.
2. Engine is running.Operating conditions for each solenoid valve are indicated. ABS
is not operating: OFF
MOTOR RELAYABS is not operating: OFF
ABS is operating: ON
ACTUATOR RELAY
Ignition switch is ON or
engine is running.Ignition switch ON (Engine stops): OFF
Engine running: ON
WARNING LAMPABS warning lamp is turned on: ON
ABS warning lamp is turned off: OFF
BATTERY VOLT Power supply voltage for control unit
ABS OPER SIGABS is not operating: OFF
ABS is operating: ON
H: 4WD model only
ACTIVE TEST MODENBBR0097S06
TEST ITEM CONDITION JUDGEMENT
FR RH SOLENOID
FR LH SOLENOID
RR SOLENOID
Engine is running.Brake fluid pressure control operation
IN SOL OUT SOL
UP (Increase): OFF OFF
KEEP (Hold): ON OFF
DOWN (Decrease): ON ON
ABS MOTORABS actuator motor
ON: Motor runs (ABS motor relay ON)
OFF: Motor stops (ABS motor relay OFF)
ABS OPER SIGIgnition switch is ON or
engine is running.ON: Set ABS OPER SIG ªONº (ABS is operating.)
OFF: Set ABS OPER SIG ªOFFº (ABS is not operating.)
G SWITCHHIgnition switch is ON.G SWITCH (G SENSOR)
ON: Set G SWITCH MONITOR ªONº (G switch circuit is
closed.)
OFF: Set G SWITCH MONITOR ªOFFº (G switch circuit is
open.)
H: 4WD models only
NOTE:
Active test will automatically stop ten seconds after the test starts. (TEST IS STOPPED monitor shows ON.)
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTIONABS
CONSULT-II Inspection Procedure (Cont'd)
BR-48

SEF233G
SEF234G
How to Perform Trouble Diagnoses for Quick
and Accurate Repair
NBBR0098INTRODUCTIONNBBR0098S01The ABS system has an electronic control unit to control major
functions. The control unit accepts input signals from sensors and
instantly drives the actuators. It is essential that both kinds of sig-
nals are proper and stable. It is also important to check for conven-
tional problems: such as air leaks in booster lines, lack of brake
fluid, or other problems with the brake system.
It is much more difficult to diagnose a problem that occurs intermit-
tently rather than continuously. Most intermittent problems are
caused by poor electric connections or faulty wiring. In this case,
careful checking of suspicious circuits may help prevent the
replacement of good parts.
A visual check only may not find the cause of the problems, so a
road test should be performed.
Before undertaking actual checks, take a few minutes to talk with
a customer who approaches with an ABS complaint. The customer
is a very good source of information on such problems; especially
intermittent ones. By talking to the customer, find out what symp-
toms are present and under what conditions they occur. Start your
diagnosis by looking for ªconventionalº problems first. This is one
of the best ways to troubleshoot brake problems on an ABS con-
trolled vehicle.
Also check related Service bulletins for information.
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TROUBLE DIAGNOSIS Ð INTRODUCTIONABS
How to Perform Trouble Diagnoses for Quick and Accurate Repair
BR-49

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

2 CHECK MECHANICAL BRAKE SYSTEM PERFORMANCE
Disconnect ABS actuator and electric unit connector and check whether brake is effective.
Does brake system function properly when brake pedal is depressed?
Ye s©GO TO 3.
No©Perform Preliminary Check. Refer to BR-50.
3 CHECK WARNING LAMP INDICATION
Ensure warning lamp remains off while driving.
SBR672E
Is warning lamp turned off?
Ye s©GO TO 4.
No©Carry out self-diagnosis. Refer to BR-41, BR-44.
4 CHECK WHEEL SENSOR
1. Check wheel sensor connector for terminal damage or loose connection.
2. Perform wheel sensor mechanical check. Refer to ª7. CHECK SENSOR ROTORº in ªDIAGNOSTIC PROCEDUREº,
ªWheel Sensor or Rotorº, BR-56.
Is wheel sensor mechanism OK?
Ye s©Check ABS actuator and electric unit pin terminals for damage or the connection of ABS
actuator and electric unit harness connector.
Reconnect ABS actuator and electric unit harness connector.
Then retest.
No©Repair.
3. Long Stopping DistanceNBBR0109
1 CHECK MECHANICAL BRAKE SYSTEM PERFORMANCE
Disconnect ABS actuator and electric unit connector and check whether stopping distance is still long.
Does brake system function properly when brake pedal is depressed?
Ye s©Perform Preliminary Check and air bleeding (if necessary).
No©Go to ª3. CHECK WARNING LAMP INDICATIONº in ª2. Unexpected Pedal Actionº,
BR-70.
TROUBLE DIAGNOSES FOR SYMPTOMSABS
2. Unexpected Pedal Action (Cont'd)
BR-70

8. Vehicle Vibrates Excessively When ABS Is
Operating
=NBBR0078IWhile ABS is operating, brake pedal vibrates slightly. This is
not a problem.
IIf vehicle vibration is greater in the AUTO mode than in the
2WD mode, there is the possibility of failure in the communi-
cation line between the ABS control unit and transfer control
unit. Check and locate the cause of the problem.
1 INSPECTION START
Inspection for excessive vibration of vehicle
SBR508E
©GO TO 2.
2 CARRY OUT SELF-DIAGNOSIS
Perform self-diagnosis for the ABS actuator and electric unit and transfer control unit.
Are there any malfunctions?
Ye s©GO TO 3.
No©GO TO 4.
3 INSPECTION OR REPAIR
Inspect or repair the system according to the self-diagnostic item.
OK©GO TO 4.
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TROUBLE DIAGNOSES FOR SYMPTOMSABS
8. Vehicle Vibrates Excessively When ABS Is Operating
BR-77

ABS Actuator and Electric UnitNBBR0079S07
SBR468E
REMOVALNBBR0079S07011. Disconnect battery cable.
2. Drain brake fluid. Refer to ªChanging Brake Fluidº, BR-7.
3. Remove mounting bracket fixing bolts and nuts.
4. Disconnect connector, brake pipes and remove fixing nuts and
actuator ground cable.
INSTALLATIONNBBR0079S0702CAUTION:
After installation, refill brake fluid. Then bleed air. Refer to
ªBleeding Brake Systemº, BR-8.
1. Tighten actuator ground cable.
Place ground cable at a notch of mounting bracket.
2. Connect brake pipes temporarily.
3. Tighten fixing bolts and nuts.
4. Tighten brake pipes.
5. Connect connector and battery cable.
REMOVAL AND INSTALLATIONABS
ABS Actuator and Electric Unit
BR-82