1998 NISSAN PATROL Brake System Workshop Manual

Diagnostic Procedure 4 (Low voltage)
Malfunction code No. 57
CHECK CONNECTOR.
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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
cNo Inspection end
CHECK ABS CONTROL UNIT POWER
SUPPLY CIRCUIT.
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1. Disconnect ABS actuator and electric unit connector.
2. Check voltage between ABS actuator and electric unit connector
E18(body
side) terminal j15and ground.
Battery voltage should exist when
ignition switch is turned ON.
OK
cNG jA(See below.)
CHECK ABS CONTROL UNIT GROUND.
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Refer to ABS ACTUATOR AND ELEC-
TRIC UNIT GROUND in Ground Circuit
Check, BR-56.
OK
cNG Repair harness and con-
nector.
CHECK HARNESS CONNECTOR.
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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.
jA
CHECK FUSE.
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Check 7.5A fuse
7. For fuse layout, refer
to POWER SUPPLY ROUTING in EL sec-
tion.
OK
cNG Replace fuse.
CHECK ABS CONTROL UNIT POWER
SUPPLY CIRCUIT.
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Check continuity between battery and
ABS actuator and electric unit connector
E18(body side) terminal j15.
OK
cNG
Check the following.
+Harness connector
E18+Harness for open or
short between ABS
actuator and electric unit
and fuse
If NG, repair harness or
connector.
CHECK BATTERY.
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Check battery. Refer to BATTERY in EL
section.
SBR200E
SBR058EB
.
.
.
.
.
.
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMS
BR-63

Diagnostic Procedure 5 (G sensor)
Malfunction code No. 17
CHECK G SENSOR POWER SUPPLY
CIRCUIT.
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Check 7.5A fuse
7. For fuse layout, refer
to POWER SUPPLY ROUTING in EL sec-
tion.
OK
cNG Replace fuse.
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
cNo Inspection end
CHECK G SENSOR.
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Refer to G SENSOR in Electrical Compo-
nents Inspection, BR-64.
OK
cNG Replace G sensor.
CHECK G SENSOR POWER SUPPLY
CIRCUIT.
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1. Disconnect G sensor connector.
2. Check voltage between G sensor con- nector
:B34,B33,:B121,
B120(body side) terminal j15and
ground.
Battery voltage should exist.
OK
cNG Check the following.
+Harness connectors
:B34,B33,E18,
:B121,B120,E18
+Harness for open or short
between G sensor and
ABS actuator and electric
unit
If NG, repair harness or
connectors.
CHECK G SENSOR GROUND.
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1. Disconnect ABS actuator and electric unit connector and G sensor connectors.
2. Check continuity between ABS actuator and electric unit connector
E18(body
side) terminals j
10,j20and G sensor
connectors
:B34,B33,:
B121,B120(body side) terminals j10,j20.
Continuity should exist.
OK
cNG Check the following.
+Harness connectors
:B34,B33,E18,
:B121,B120,B18
+Harness for open or short
between G sensor and
ABS actuator and electric
unit
If NG, repair harness or
connectors.
CHECK HARNESS CONNECTOR.
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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.
SBR201E
SBR202E
SBR203E
.
.
.
.
.
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMS
BR-64

ELECTRICAL COMPONENTS INSPECTION
G sensor
CAUTION:
The G sensor is easily damaged if it sustains an impact. Be
careful not to drop or bump it.
1. Measure resistance between terminalsj
15andj20of G sensor
unit connector.
G sensor condition Resistance between
terminals j15andj20
G sensor switch
condition
Installed in vehicle 1.4 - 1.6 k W``ON''
Tilted as shown in ®gure 4.7 - 5.5 k W``OFF''
2. Measure resistance between terminals j10andj15of the G
sensor unit connector.
Resistance: 70 - 124 W
Diagnostic Procedure 6 (Control unit)
Malfunction code No. 71
CHECK CONNECTOR.
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1. Disconnect ABS actuator and electric unit connector.
Check terminals for damage or loose
connections. Then reconnect connector.
2. Carry out self-diagnosis again. Does warning lamp activate again?
Ye s
cNo Inspection end
ABS CONTROL UNIT POWER SUPPLY
CHECK
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Check voltage. Refer to
in Diagnostic
Procedure 4, BR-63.
CHECK SELF-DIAGNOSTIC RESULTS
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Does warning lamp indicate code No. 71
again?
No
cYe s Replace ABS actuator and
electric unit.
INSPECTION
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Inspect the system according to the code
No.
SBR844DC
SBR204E.
.
.
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC ITEMS
Diagnostic Procedure 5 (G sensor) (Cont'd)
BR-65

Diagnostic Procedure 7 (ABS works
frequently.)
CHECK BRAKE FLUID PRESSURE.
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Check brake ¯uid pressure distribution.
Refer to proportioning valve inspection.
OK
cNG Perform Preliminary
Check, refer to BR-40.
CHECK WHEEL SENSOR.
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1. Check wheel sensor connector for ter- minal damage or loose connections.
2. Perform wheel sensor mechanical check.
Refer to Diagnostic Procedure 1,
BR-57.
OK
cNG Repair.
CHECK FRONT AXLES.
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Check front axles for excessive loose-
ness. Refer to FA section (``Front Wheel
Bearing'', ``ON-VEHICLE SERVICE'').
OK
cNG Repair.
Go toin Diagnostic Procedure 8,
BR-66.
.
.
.
TROUBLE DIAGNOSES FOR SYMPTOMS
BR-66

Diagnostic Procedure 8 (Unexpected pedal
action)
CHECK BRAKE PEDAL STROKE.
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Check brake pedal stroke. Is stroke
excessively large?
No
cYe s Perform Preliminary
Check, refer to BR-40.
CHECK BRAKE PERFORMANCE.
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Disconnect ABS actuator and electric unit
connector and check whether brake is
effective.
Ye s
cNo Perform Preliminary
Check, refer to BR-40.
CHECK WARNING LAMP ACTIVATE.
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Ensure warning lamp remains off while
driving.
OK
cNG Carry out self-diagnosis.
Refer to BR-47, 51.
CHECK WHEEL SENSOR.
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1. Check wheel sensor connector for ter- minal damage or loose connection.
2. Perform wheel sensor mechanical check.
Refer to Diagnostic Procedure 1,
BR-57.
OK
cNG Repair.
CHECK HARNESS CONNECTOR.
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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.
Diagnostic Procedure 9 (Long stopping
distance)
CHECK ABS PERFORMANCE.
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Disconnect ABS actuator and electric unit
connector and check whether stopping
distance is still long.
Ye s
cNo Go toin Diagnostic
Procedure 8, BR-67.
Perform Preliminary Check and air bleed-
ing.
Note: Stopping distance may be larger than vehicles without ABS when road condition is slippery.
SBR540A
SBR186E
.
.
.
.
.
TROUBLE DIAGNOSES FOR SYMPTOMS
BR-67

Diagnostic Procedure 10 (ABS does not work.)
CHECK WARNING LAMP ACTIVATE.
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Does the ABS warning lamp activate?
No
cYe s Carry out self-diagnosis.
Refer to BR-47, 51.
Go toin Diagnostic Procedure 8,
BR-67.
Note: ABS does not work when vehicle speed is under 10 km/h (6 MPH).
Diagnostic Procedure 11 (Pedal vibration and
noise)
INSPECTION START
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1. Apply brake.
2. Start engine.
3. Does the symptom appear only when engine is started?
No
cYe s Carry out self-diagnosis.
Refer to BR-47, 51.
CHECK IF SYMPTOM APPEARS.
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Does the symptom appear when electrical
equipment switches (such as headlamp)
are operated?
Ye s
cNo Go toin Diagnostic
Procedure 8, BR-67.
CHECK WHEEL SENSOR.
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Check wheel sensor shield ground. For
location of shield ground, refer to wiring
diagram and ``HARNESS LAYOUT'' in EL
section.
OK
cNG Repair wheel sensor.
CHECK HARNESS CONNECTOR.
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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.
SAT797A
.
.
.
.
TROUBLE DIAGNOSES FOR SYMPTOMS
BR-68

Note: ABS may operate and cause vibration under any of thefollowing conditions.
+ Applying brake gradually when shifting or operating
clutch.
+ Low friction (slippery) road.
+ High speed cornering.
+ Driving over bumps and pot holes.
+ Engine speed is over 5,000 rpm with vehicle stopped.
Diagnostic Procedure 12 (Warning lamp does
not come on when ignition switch is turned
ON.)
CHECK FUSE.
- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Check 10A fuse
28. For fuse layout, refer
to POWER SUPPLY ROUTING in EL sec-
tion.
OK
cNG Replace fuse.
CHECK WARNING LAMP ACTIVATE.
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Disconnect ABS actuator and electric unit
connector.
Does the warning lamp activate?
No
cYe s jA(Go to next page.)
CHECK HARNESS FOR SHORT.
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1. Disconnect ABS actuator and electric unit connector.
2. Check voltage between ABS actuator and electric unit connector
E18(body
side) terminal j
21and ground.
Battery voltage should not exist.
OK
cNG Repair harness or connec-
tor.
CHECK COMBINATION METER.
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Check combination meter. Refer to
WARNING LAMPS in EL section.
SBR205E
SBR186E
SBR144EB
.
.
.
TROUBLE DIAGNOSES FOR SYMPTOMS
Diagnostic Procedure 11 (Pedal vibration and
noise) (Cont'd)
BR-69

jA
CHECK HARNESS CONNECTOR.
- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Check ABS actuator and electric unit pin
terminals for damage or connection of
ABS actuator and electric unit harness
connector. Reconnect ABS actuator and
electric unit harness connector. Then
retest.
NG
cOK Inspection end
REPLACE.
- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Replace ABS actuator and electric unit.
.
.
TROUBLE DIAGNOSES FOR SYMPTOMS
Diagnostic Procedure 12 (Warning lamp does
not come on when ignition switch is turned
ON.) (Cont'd)
BR-70