2001 INFINITI QX4 Electrical

DescriptionNBAT0039IThis is an OBD-II self-diagnostic item and not available in TCM
self-diagnosis.
IThis malfunction will not be detected while the O/D OFF indi-
cator lamp is indicating another self-diagnosis malfunction.
IThis malfunction is detected when the A/T does not shift into
first gear position as instructed by the TCM. This is not caused
by electrical malfunction (circuits open or shorted) but by
mechanical malfunction such as control valve sticking,
improper solenoid valve operation, etc.
Gear position1234
Shift solenoid valve A ON (Closed) OFF (Open) OFF (Open) ON (Closed)
Shift solenoid valve B ON (Closed) ON (Closed) OFF (Open) OFF (Open)
TCM TERMINALS AND REFERENCE VALUENBAT0039S02Remarks: Specification data are reference values.
Terminal
No.Wire color Item ConditionJudgement
standard
(Approx.)
11 L/WShift solenoid
valve A
When shift solenoid valve A operates.
(When driving in ªD
1ºorªD4º.)Battery volt-
age
When shift solenoid valve A does not operate.
(When driving in ªD
2ºorªD3º.)0V
12 L/RShift solenoid
valve BWhen shift solenoid valve B operates.
(When driving in ªD
1ºorªD2º.)Battery volt-
age
When shift solenoid valve B does not operate.
(When driving in ªD
3ºorªD4º.)0V
ON BOARD DIAGNOSIS LOGICNBAT0039S03This diagnosis monitors actual gear position by checking the torque
converter slip ratio calculated by TCM as follows:
Torque converter slip ratio = A x C/B
A: Output shaft revolution signal from revolution sensor
B: Engine speed signal from ECM
C: Gear ratio determined as gear position which TCM supposes
If the actual gear position is higher than the position (1st) supposed
by TCM, the slip ratio will be more than normal. In case the ratio
exceeds the specified value, TCM judges this diagnosis malfunc-
tion.
This malfunction will be caused when either shift solenoid valve A
is stuck open or shift solenoid valve B is stuck open.
Gear position supposed by TCM1234
In case of gear position with no malfunctions1234
In case of gear position with shift solenoid valve A stuck open 2* 2 3 3
In case of gear position with shift solenoid valve B stuck open 4* 3 3 4
*: P0731 is detected.
Diagnostic trouble code Malfunction is detected when ... Check item (Possible cause)
: A/T 1ST GR FNCTN
A/T cannot be shifted to the 1st gear
position even if electrical circuit is good.IShift solenoid valve A
IShift solenoid valve B
IEach clutch
IHydraulic control circuit
: P0731
DTC P0731 IMPROPER SHIFTING TO 1ST GEAR POSITION
Description
AT-120

DescriptionNBAT0042IThis is an OBD-II self-diagnostic item and not available in TCM
self-diagnosis.
IThis malfunction will not be detected while the O/D OFF indi-
cator lamp is indicating another self-diagnosis malfunction.
IThis malfunction is detected when the A/T does not shift into
second gear position as instructed by the TCM. This is not
caused by electrical malfunction (circuits open or shorted) but
by mechanical malfunction such as control valve sticking,
improper solenoid valve operation, etc.
Gear position1234
Shift solenoid valve A ON (Closed) OFF (Open) OFF (Open) ON (Closed)
Shift solenoid valve B ON (Closed) ON (Closed) OFF (Open) OFF (Open)
TCM TERMINALS AND REFERENCE VALUENBAT0042S02Remarks: Specification data are reference values.
Terminal
No.Wire color Item ConditionJudgement
standard
(Approx.)
12 L/RShift solenoid
valve B
When shift solenoid valve B operates.
(When driving in ªD
1ºorªD2º.)Battery volt-
age
When shift solenoid valve B does not operate.
(When driving in ªD
3ºorªD4º.)0V
ON BOARD DIAGNOSIS LOGICNBAT0042S03This diagnosis monitors actual gear position by checking the torque
converter slip ratio calculated by TCM as follows:
Torque converter slip ratio = A x C/B
A: Output shaft revolution signal from revolution sensor
B: Engine speed signal from ECM
C: Gear ratio determined as gear position which TCM supposes
If the actual gear position is higher than the position (2nd) sup-
posed by TCM, the slip ratio will be more than normal. In case the
ratio exceeds the specified value, TCM judges this diagnosis mal-
function.
This malfunction will be caused when shift solenoid valve B is stuck
open.
Gear position supposed by TCM 1 2 3 4
In case of gear position with no malfunctions 1 2 3 4
In case of gear position with shift solenoid valve B
stuck open43* 3 4
*: P0732 is detected.
Diagnostic trouble code Malfunction is detected when ... Check item (Possible cause)
: A/T 2ND GR FNCTN
A/T cannot be shifted to the 2nd gear
position even if electrical circuit is good.IShift solenoid valve B
IEach clutch
IHydraulic control circuit
: P0732
DTC P0732 IMPROPER SHIFTING TO 2ND GEAR POSITION
Description
AT-126

DescriptionNBAT0045IThis is an OBD-II self-diagnostic item and not available in TCM
self-diagnosis.
IThis malfunction will not be detected while the O/D OFF indi-
cator lamp is indicating another self-diagnosis malfunction.
IThis malfunction is detected when the A/T does not shift into
third gear position as instructed by the TCM. This is not caused
by electrical malfunction (circuits open or shorted) but by
mechanical malfunction such as control valve sticking,
improper solenoid valve operation, malfunctioning servo piston
or brake band, etc.
Gear position1234
Shift solenoid valve A ON (Closed) OFF (Open) OFF (Open) ON (Closed)
Shift solenoid valve B ON (Closed) ON (Closed) OFF (Open) OFF (Open)
TCM TERMINALS AND REFERENCE VALUENBAT0045S02Remarks: Specification data are reference values.
Terminal
No.Wire color Item ConditionJudgement
standard
(Approx.)
11 L/WShift solenoid
valve A
When shift solenoid valve A operates.
(When driving in ªD
1ºorªD4º.)Battery volt-
age
When shift solenoid valve A does not operate.
(When driving in ªD
2ºorªD3º.)0V
ON BOARD DIAGNOSIS LOGICNBAT0045S03This diagnosis monitors actual gear position by checking the torque
converter slip ratio calculated by TCM as follows:
Torque converter slip ratio = A x C/B
A: Output shaft revolution signal from revolution sensor
B: Engine speed signal from ECM
C: Gear ratio determined as gear position which TCM supposes
If the actual gear position is higher than the position (3rd) supposed
by TCM, the slip ratio will be more than normal. In case the ratio
exceeds the specified value, TCM judges this diagnosis malfunc-
tion.
This malfunction will be caused when shift solenoid valve A is stuck
closed.
Gear position supposed by TCM1234
In case of gear position with no malfunctions1234
In case of gear position with shift solenoid valve A
stuck closed1 1 4* 4
*: P0733 is detected.
Diagnostic trouble code Malfunction is detected when ... Check item (Possible cause)
: A/T 3RD GR FNCTN
A/T cannot be shifted to the 3rd gear
position even if electrical circuit is good.IShift solenoid valve A
IEach clutch
IHydraulic control circuit
: P0733
DTC P0733 IMPROPER SHIFTING TO 3RD GEAR POSITION
Description
AT-132

ON BOARD DIAGNOSIS LOGIC=NBAT0048S03This diagnosis monitors actual gear position by checking the torque
converter slip ratio calculated by TCM as follows:
Torque converter slip ratio = A x C/B
A: Output shaft revolution signal from revolution sensor
B: Engine speed signal from ECM
C: Gear ratio determined as gear position which TCM supposes
If the actual gear position is much lower than the position (4th)
supposed by TCM, the slip ratio will be much less than normal. In
case the ratio does not reach the specified value, TCM judges this
diagnosis malfunction.
This malfunction will be caused when shift solenoid valve B is stuck
closed.
Gear position supposed by TCM1234
In case of gear position with no malfunctions1234
In case of gear position with shift solenoid valve B
stuck closed1221*
*: P0734 is detected.
Diagnostic trouble code Malfunction is detected when ... Check item (Possible cause)
: A/T 4TH GR FNCTN
A/T cannot be shifted to the 4th gear
position even if electrical circuit is good.IShift solenoid valve A
IShift solenoid valve B
ILine pressure solenoid valve
IEach clutch
IHydraulic control circuit
: P0734
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DTC P0734 IMPROPER SHIFTING TO 4TH GEAR POSITION
Description (Cont'd)
AT-139

ABS
DESCRIPTION...............................................................32
Purpose......................................................................32
Operation ...................................................................32
ABS Hydraulic Circuit ................................................32
System Components .................................................33
System Description ....................................................33
SENSOR.................................................................33
CONTROL UNIT (BUILT-IN ABS ACTUATOR AND
ELECTRIC UNIT)
.....................................................33
ABS ACTUATOR AND ELECTRIC UNIT....................33
G SENSOR (4WD MODELS ONLY)..........................34
Component Parts and Harness Connector
Location .....................................................................35
Schematic ..................................................................36
Wiring Diagram - ABS - .............................................37
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION...............................................................41
Self-diagnosis ............................................................41
FUNCTION..............................................................41
SELF-DIAGNOSIS PROCEDURE..............................41
HOW TO READ SELF-DIAGNOSTIC RESULTS
(MALFUNCTION CODES)
........................................42
HOW TO ERASE SELF-DIAGNOSTIC RESULTS
(MALFUNCTION CODES)
........................................42
CONSULT-II ...............................................................43
CONSULT-II APPLICATION TO ABS..........................43
ECU (ABS CONTROL UNIT) PART NUMBER
MODE
.....................................................................43
CONSULT-II Inspection Procedure............................44
SELF-DIAGNOSIS PROCEDURE..............................44
SELF-DIAGNOSTIC RESULTS MODE.......................45
DATA MONITOR PROCEDURE................................46
ACTIVE TEST PROCEDURE....................................47
DATA MONITOR MODE...........................................48
ACTIVE TEST MODE...............................................48
TROUBLE DIAGNOSIS - INTRODUCTION..................49
How to Perform Trouble Diagnoses for Quick
and Accurate Repair ..................................................49
INTRODUCTION......................................................49
TROUBLE DIAGNOSIS - BASIC INSPECTION...........50
Preliminary Check......................................................50
Ground Circuit Check ................................................53
ABS ACTUATOR AND ELECTRIC UNIT GROUND.....53
TROUBLE DIAGNOSIS - GENERAL
DESCRIPTION...............................................................54
Malfunction Code/Symptom Chart.............................54
TROUBLE DIAGNOSES FOR SELF-DIAGNOSTIC
ITEMS.............................................................................56Wheel Sensor or Rotor ..............................................56
DIAGNOSTIC PROCEDURE.....................................56
ABS Actuator Solenoid Valve or Solenoid Valve
Relay ..........................................................................59
DIAGNOSTIC PROCEDURE.....................................59
Motor Relay or Motor.................................................61
DIAGNOSTIC PROCEDURE.....................................61
Low Voltage ...............................................................63
DIAGNOSTIC PROCEDURE.....................................63
G Sensor and Circuit .................................................65
DIAGNOSTIC PROCEDURE.....................................65
ELECTRICAL COMPONENT INSPECTION................67
Control Unit ................................................................68
DIAGNOSTIC PROCEDURE.....................................68
TROUBLE DIAGNOSES FOR SYMPTOMS.................69
1. ABS Works Frequently ..........................................69
2. Unexpected Pedal Action ......................................69
3. Long Stopping Distance ........................................70
4. ABS Does Not Work ..............................................71
5. Pedal Vibration and Noise.....................................71
6. Warning Lamp Does Not Come On When
Ignition Switch Is Turned On .....................................72
7. Warning Lamp Stays On When Ignition Switch
Is Turned On ..............................................................74
8. Vehicle Vibrates Excessively When ABS Is
Operating ...................................................................77
REMOVAL AND INSTALLATION.................................80
Front Wheel Sensor...................................................80
Rear Wheel Sensor ...................................................80
Front Sensor Rotor ....................................................81
REMOVAL...............................................................81
INSTALLATION........................................................81
Rear Sensor Rotor.....................................................81
REMOVAL...............................................................81
INSTALLATION........................................................81
G Sensor....................................................................81
ABS Actuator and Electric Unit..................................82
REMOVAL...............................................................82
INSTALLATION........................................................82
SERVICE DATA AND SPECIFICATIONS (SDS).........83
General Specifications ...............................................83
Disc Brake .................................................................83
Drum Brake................................................................83
Brake Pedal ...............................................................83
Parking Brake Control ...............................................84
CONTENTS(Cont'd)
BR-2

Supplemental Restraint System (SRS) ªAIR
BAGº and ªSEAT BELT PRE-TENSIONERº
NBBR0001The 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 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.
SBR686C
Precautions for Brake SystemNBBR0002IUse brake fluid ªDOT 3º.
INever reuse drained brake fluid.
IBe careful not to splash brake fluid on painted areas; it
may cause paint damage. If brake fluid is splashed on
painted areas, wash it away with water immediately.
ITo clean master cylinder parts, disc brake caliper parts or
wheel cylinder parts, use clean brake fluid.
INever use mineral oils such as gasoline or kerosene. They
will ruin rubber parts of hydraulic system.
IUse flare nut wrench when removing and installing brake
tubes.
IAlways torque brake lines when installing.
WARNING:
IClean brakes with a vacuum dust collector to minimize
risk of health hazard from powder caused by friction.
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PRECAUTIONS
Supplemental Restraint System (SRS) ªAIR BAGº and ªSEAT BELT PRE-TENSIONERº
BR-3

Wiring Diagrams and Trouble DiagnosesNBBR0003When you read wiring diagrams, refer to the following:
IGI-11, ªHOW TO READ WIRING DIAGRAMSº
IEL-9, ªPOWER SUPPLY ROUTINGº for power distribution circuit
When you perform trouble diagnoses, refer to the following:
IGI-35, ªHOW TO FOLLOW TEST GROUP IN TROUBLE DIAGNOSESº
IGI-24, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº
PRECAUTIONS
Wiring Diagrams and Trouble Diagnoses
BR-4

System ComponentsNBBR0090
SBR447EB
SBR124B
System DescriptionNBBR0091SENSORNBBR0091S01The sensor unit consists of a gear-shaped sensor rotor and a sen-
sor element. The element contains a bar magnet around which a
coil is wound. The front sensors are installed on the front spindles
and the rear sensors are installed on the rear spindles. As the
wheel rotates, the sensor generates a sine-wave pattern. The fre-
quency and voltage increase(s) as the rotating speed increases.
SBR668E
CONTROL UNIT (BUILT-IN ABS ACTUATOR AND
ELECTRIC UNIT)
NBBR0091S02The control unit computes the wheel rotating speed by the signal
current sent from the sensor. Then it supplies a DC current to the
actuator solenoid valve. It also controls ON-OFF operation of the
valve relay and motor relay. If any electrical malfunction should be
detected in the system, the control unit causes the warning lamp
to light up. In this condition, the ABS will be deactivated by the
control unit, and the vehicle's brake system reverts to normal
operation. (For control unit layout, refer to ABS ACTUATOR AND
ELECTRIC UNIT, BR-33.)
SBR482E
ABS ACTUATOR AND ELECTRIC UNITNBBR0091S03The ABS actuator and electric unit contains:
IAn electric motor and pump
ITwo relays
ISix solenoid valves, each inlet and outlet for
Ð LH front
Ð RH front
Ð Rear
IABS control unit
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DESCRIPTIONABS
System Components
BR-33