2001 INFINITI QX4 IDX

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

4 CHECK BRAKE BOOSTER OPERATION
Check brake booster for operation and air tightness.
Refer to ªOn-vehicle Serviceº, ªBRAKE BOOSTERº, BR-19.
SBR058C
Is brake booster airtight and functioning properly?
Ye s©GO TO 5.
No©Replace. GO TO 5.
5 CHECK BRAKE PAD AND ROTOR
Check brake pad and rotor.
Refer to (BR-22, BR-24).
SBR059C
Are brake pads and rotors functioning properly?
Ye s©GO TO 6.
No©Replace.
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TROUBLE DIAGNOSIS Ð BASIC INSPECTIONABS
Preliminary Check (Cont'd)
BR-51

SBR484E
Ground Circuit Check=NBBR0100ABS ACTUATOR AND ELECTRIC UNIT GROUNDNBBR0100S01ICheck continuity between ABS actuator and electric unit con-
nector terminals and ground.
Continuity should exist.GI
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TROUBLE DIAGNOSIS Ð BASIC INSPECTIONABS
Ground Circuit Check
BR-53

*3: The trouble code ª61º can sometimes appear when the ABS motor is not properly grounded. If it appears, be sure to check the con-
dition of the ABS motor ground circuit connection.
*4: 4WD models only
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTIONABS
Malfunction Code/Symptom Chart (Cont'd)
BR-55

3 CHECK WHEEL SENSOR ELECTRICAL
1. Disconnect ABS actuator and electric unit connector.
2. Check resistance between ABS actuator and electric unit connector E111 (body side) terminals.
Code No. 21 or 22 (Front RH wheel)
Terminals 4 and 5
Code No. 25 or 26 (Front LH wheel)
Terminals 6 and 7
Code No. 31 or 32 (Rear RH wheel)
Terminals 1 and 2
Code No. 35 or 36 (Rear LH wheel)
Terminals 8 and 9
SBR486E
Resistance:
Front 0.9 - 1.1 kW
Rear 1.44 - 1.76 kW
Is front resistance 0.9 - 1.1 kWand rear resistance 1.44 - 1.76 kW?
Ye s©GO TO 5.
No©GO TO 4.
4 CHECK WHEEL SENSOR
Check each sensor for resistance.
SBR487E
Resistance:
Front 0.9 - 1.1 kW
Rear 1.44 - 1.76 kW
Is front resistance 0.9 - 1.1 kWand rear resistance 1.44 - 1.76 kW?
Ye s©Check the following.
If NG, repair harness or connectors.
IHarness connectors E111, E14, E51, B8, B69
IHarness for open or short between wheel sensor connectors and ABS actuator and
electric unit
No©Replace wheel sensor.
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TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
Wheel Sensor or Rotor (Cont'd)
BR-57

ABS Actuator Solenoid Valve or Solenoid Valve
Relay
DIAGNOSTIC PROCEDURE=NBBR0103Malfunction code No. 41, 45, 55, 42, 46, 56, 63
1 INSPECTION START
Solenoid valve relay inspection
SBR488E
©GO TO 2.
2 CHECK FUSIBLE LINK
Check 40A fusible linkc. For fusible link layout, refer to EL-16, ªPOWER SUPPLY ROUTINGº.
Is fusible link OK?
Ye s©GO TO 3.
No©GO TO 6.
3 CHECK CONNECTOR
1. Disconnect connector from ABS actuator and electric unit. 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 4.
No©INSPECTION END
4 CHECK ABS ACTUATOR AND ELECTRIC UNIT GROUND CIRCUIT
Refer to ªABS ACTUATOR AND ELECTRIC UNIT GROUNDº in ªGround Circuit Checkº, BR-53.
Is ground circuit OK?
Ye s©GO TO 5.
No©Repair harness or connector.
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TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
ABS Actuator Solenoid Valve or Solenoid Valve Relay
BR-59

Motor Relay or Motor
DIAGNOSTIC PROCEDURE=NBBR0104Malfunction code No. 61
1 INSPECTION START
ABS motor relay inspection
SBR491E
©GO TO 2.
2 CHECK FUSIBLE LINK
Check 40A fusible linkd. For fusible link layout, refer to EL-16, ªPOWER SUPPLY ROUTINGº.
Is fusible link OK?
Ye s©GO TO 3.
No©GO TO 6.
3 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 4.
No©INSPECTION END
4 CHECK ABS ACTUATOR AND ELECTRIC UNIT GROUND CIRCUIT
Refer to ªABS ACTUATOR AND ELECTRIC UNIT GROUNDº in ªGround Circuit Checkº, BR-53.
Is ground circuit OK?
Ye s©GO TO 5.
No©Repair harness or connector.
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TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
Motor Relay or Motor
BR-61

Low Voltage
DIAGNOSTIC PROCEDURENBBR0105Malfunction code No. 57
1 INSPECTION START
ABS actuator and electric unit power supply and ground circuit inspection
SBR494E
©GO TO 2.
2 CHECK FUSE
Check 7.5A fuse No. 7. For fuse layout, refer to EL-16, ªPOWER SUPPLY ROUTINGº.
Is fuse OK?
Ye s©GO TO 3.
No©GO TO 6.
3 CHECK CONNECTOR
1. Disconnect ABS actuator and electric unit connector. Check terminals for damage or loose connections. Then recon-
nect connector.
2. Carry out self-diagnosis again.
Does warning lamp activate again?
Ye s©GO TO 4.
No©INSPECTION END
4 CHECK ABS ACTUATOR AND ELECTRIC UNIT GROUND CIRCUIT
Refer to ªABS ACTUATOR AND ELECTRIC UNIT GROUNDº in ªGround Circuit Checkº, BR-53.
Is ground circuit OK?
Ye s©GO TO 5.
No©Repair harness or connector.
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TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
Low Voltage
BR-63