2001 INFINITI QX4 02 sensor

Wheel Sensor or Rotor
DIAGNOSTIC PROCEDURENBBR0102Malfunction code No. 21, 22, 25, 26, 31, 32, 35, 36 or 18
NOTE:
Wheel position should be distinguished by code No. except code
No. 18 (sensor rotor).
1 INSPECTION START
Wheel sensor inspection
SBR485E
©GO TO 2.
2 CHECK CONNECTOR
1. Disconnect connectors from ABS actuator and electric unit and wheel sensor of malfunction code No. Check terminals
for damage or loose connection. Then reconnect connectors.
2. Carry out self-diagnosis again.
Does warning lamp activate again?
Ye s©GO TO 3.
No©INSPECTION END
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
Wheel Sensor or Rotor
BR-56

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.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
Wheel Sensor or Rotor (Cont'd)
BR-57

5 CHECK TIRE
Check for inflation pressure, wear and size of each tire. (See NOTE)
Are tire pressure and size correct and is tire wear within specifications?
Ye s©GO TO 6.
No©Adjust tire pressure or replace tire(s). (See NOTE)
6 CHECK WHEEL BEARING
Check wheel bearing axial end play. (See NOTE)
Is wheel bearing axial end play within specifications? Refer to AX-4, ªFront Wheel Bearingº and AX-18, ªRear
Wheel Bearingº.
Ye s©GO TO 7.
No©Check wheel bearing. Refer to AX-4, ªFront Wheel Bearingº and AX-18, ªRear Wheel
Bearingº.
7 CHECK SENSOR ROTOR
Check sensor rotor for teeth damage. (See NOTE)
Is sensor rotor free from damage?
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©Replace sensor rotor. (See NOTE)
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
Wheel Sensor or Rotor (Cont'd)
BR-58

G Sensor and Circuit
DIAGNOSTIC PROCEDURENBBR0114Malfunction code No. 17
1 INSPECTION START
G sensor inspection
SBR504E
©GO TO 2.
2 CHECK FUSE
Check 7.5A fuse No. 7 for ABS actuator and electric unit. For fuse layout, refer to EL-16, ªPOWER SUPPLY ROUTINGº.
Is fuse OK?
Ye s©GO TO 3.
No©Replace fuse.
3 CHECK CONNECTOR
1. Disconnect connectors from ABS actuator and electric unit and G sensor. Check terminals for damage or loose connec-
tion. Then reconnect connectors.
2. Carry out self-diagnosis again.
Does warning lamp activate again?
Ye s©GO TO 4.
No©INSPECTION END
4 CHECK G SENSOR
Refer to ªG SENSORº in ªElectrical Components Inspectionº, BR-67.
Is resistance within specifications?
Ye s©GO TO 5.
No©Replace G sensor.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
G Sensor and Circuit
BR-65

5 CHECK G SENSOR POWER SUPPLY CIRCUIT
Check voltage between G sensor connector terminals 1, 2 and ground.
SBR861D
Does battery voltage exist?
Ye s©GO TO 6.
No©Check the following. If NG, repair harness or connectors.
IHarness connectors B58, B81
IHarness for open or short between G sensor and fuse
6 CHECK CIRCUIT
1. Disconnect harness connector from ABS actuator and electric unit.
2. Check continuity between ABS actuator and electric unit connector terminals 20, 10 and G sensor connector terminals
17, 51.
SBR505E
Does continuity exist?
Ye s©Check actuator and electric unit pin terminals for damage or the connection of actuator
and electric unit harness connector. Reconnect actuator and electric unit harness con-
nector. Then retest.
No©Check the following. If NG, repair harness or connectors.
IHarness connectors E111, B58, B81
IHarness for open or short between G sensor connector and actuator and electric unit
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
G Sensor and Circuit (Cont'd)
BR-66

SBR844DF
ELECTRICAL COMPONENT INSPECTION=NBBR0115G Sensor (4WD models only)NBBR0115S01CAUTION:
The G sensor is easily damaged if it sustains an impact. Be
careful not to drop or bump it.
1. Measure resistance between terminals 2 and 51 of G sensor
unit connector.
G sensor conditionResistance between ter-
minals 2 and 51G sensor switch condi-
tion
Installed in vehicle 1.4 - 1.6 kWªONº
Tilted as shown in figure 4.7 - 5.5 kWªOFFº
2. Measure resistance between terminals 1 and 17 of the G sen-
sor unit connector.
Resistance: 70 - 124W
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMSABS
G Sensor and Circuit (Cont'd)
BR-67

1. ABS Works FrequentlyNBBR0107
1 CHECK BRAKE FLUID PRESSURE
Check brake fluid pressure distribution.
Refer to ªInspectionº, ªLOAD SENSING VALVEº, BR-12.
Is brake fluid pressure distribution normal?
Ye s©GO TO 2.
No©Repair. Then perform Preliminary Check.
Refer to BR-50.
2 CHECK WHEEL SENSOR
1. Check wheel sensor connector for terminal damage or loose connections.
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©GO TO 3.
No©Repair.
3 CHECK FRONT AXLE
Check front axles for excessive looseness. Refer to AX-4, ªFront Wheel Bearingº.
Is front axle installed properly?
Ye s©Go to ª3. CHECK WARNING LAMP INDICATIONº in ª2. Unexpected Pedal Actionº,
BR-70.
No©Repair.
2. Unexpected Pedal ActionNBBR0108
1 CHECK BRAKE PEDAL STROKE
Check brake pedal stroke.
SBR540A
Is brake pedal stroke excessively large?
Ye s©Perform Preliminary Check. Refer to BR-50.
No©GO TO 2.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSES FOR SYMPTOMSABS
1. ABS Works Frequently
BR-69

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