2001 INFINITI QX4 transmission

AUTOMATIC TRANSMISSION
SECTION
AT
CONTENTS
TROUBLE DIAGNOSIS - INDEX....................................4
Alphabetical & P No. Index for DTC ...........................4
PRECAUTIONS...............................................................6
Precautions for Supplemental Restraint System
(SRS)²AIR BAG²and²SEAT BELT
PRE-TENSIONER²......................................................6
Precautions for On Board Diagnostic (OBD)
System of A/T and Engine...........................................6
Precautions ..................................................................6
Service Notice or Precautions .....................................8
Wiring Diagrams and Trouble Diagnosis .....................9
PREPARATION.............................................................10
Special Service Tools ................................................10
OVERALL SYSTEM......................................................12
A/T Electrical Parts Location .....................................12
Circuit Diagram ..........................................................13
Cross-sectional View .................................................14
Hydraulic Control Circuit ............................................15
Shift Mechanism ........................................................16
Control System ..........................................................25
Control Mechanism ....................................................26
Control Valve .............................................................31
ON BOARD DIAGNOSTIC SYSTEM
DESCRIPTION...............................................................33
Introduction ................................................................33
OBD-II Function for A/T System ................................33
One or Two Trip Detection Logic of OBD-II ..............33
OBD-II Diagnostic Trouble Code (DTC) ....................33
Malfunction Indicator Lamp (MIL) ..............................37
CONSULT-II ...............................................................37
Diagnostic Procedure Without CONSULT-II ..............46
TROUBLE DIAGNOSIS - INTRODUCTION..................53
Introduction ................................................................53
Work Flow ..................................................................57
TROUBLE DIAGNOSIS - BASIC INSPECTION...........59
A/T Fluid Check .........................................................59
Stall Test ....................................................................59
Line Pressure Test .....................................................62
Road Test...................................................................63TROUBLE DIAGNOSIS - GENERAL
DESCRIPTION...............................................................81
Symptom Chart ..........................................................81
TCM Terminals and Reference Value........................92
TROUBLE DIAGNOSIS FOR POWER SUPPLY..........96
Wiring Diagram - AT - MAIN ......................................96
Diagnostic Procedure ................................................97
DTC P0705 PARK/NEUTRAL POSITION SWITCH.....99
Description .................................................................99
Wiring Diagram - AT - PNP/SW...............................101
Diagnostic Procedure ..............................................102
Component Inspection .............................................103
DTC P0710 A/T FLUID TEMPERATURE SENSOR
CIRCUIT.......................................................................105
Description ...............................................................105
Wiring Diagram - AT - FTS ......................................107
Diagnostic Procedure ..............................................108
Component Inspection ............................................. 110
DTC P0720 VEHICLE SPEED SENSOR.A/T
(REVOLUTION SENSOR)........................................... 111
Description ............................................................... 111
Wiring Diagram - AT - VSSA/T ................................ 113
Diagnostic Procedure .............................................. 114
Component Inspection ............................................. 115
DTC P0725 ENGINE SPEED SIGNAL....................... 116
Description ............................................................... 116
Wiring Diagram - AT - ENGSS ................................ 117
Diagnostic Procedure .............................................. 118
DTC P0731 IMPROPER SHIFTING TO 1ST GEAR
POSITION....................................................................120
Description ...............................................................120
Wiring Diagram - AT - 1ST ......................................123
Diagnostic Procedure ..............................................124
Component Inspection .............................................125
DTC P0732 IMPROPER SHIFTING TO 2ND GEAR
POSITION....................................................................126
Description ...............................................................126
Wiring Diagram - AT - 2ND......................................129
Diagnostic Procedure ..............................................130
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SEF291H
IWhen connecting or disconnecting pin connectors into or
from TCM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on TCM
pin terminal, when connecting pin connectors.
MEF040DA
IBefore replacing TCM, perform TCM input/output signal
inspection and make sure whether TCM functions prop-
erly or not. (Refer to AT-92.)
SAT964I
IAfter performing each TROUBLE DIAGNOSIS, perform
ªDTC (Diagnostic Trouble Code) CONFIRMATION PROCE-
DUREº.
The DTC should not be displayed in the ªDTC CONFIRMA-
TION PROCEDUREº if the repair is completed.
IBefore proceeding with disassembly, thoroughly clean the out-
side of the transmission. It is important to prevent the internal
parts from becoming contaminated by dirt or other foreign mat-
ter.
IDisassembly should be done in a clean work area.
IUse lint-free cloth or towels for wiping parts clean. Common
shop rags can leave fibers that could interfere with the opera-
tion of the transmission.
IPlace disassembled parts in order for easier and proper
assembly.
IAll parts should be carefully cleaned with a general purpose,
non-flammable solvent before inspection or reassembly.
IGaskets, seals and O-rings should be replaced any time the
transmission is disassembled.
IIt is very important to perform functional tests whenever they
are indicated.
IThe valve body contains precision parts and requires extreme
care when parts are removed and serviced. Place disas-
sembled valve body parts in order for easier and proper
assembly. Care will also prevent springs and small parts from
becoming scattered or lost.
IProperly installed valves, sleeves, plugs, etc. will slide along
bores in valve body under their own weight.
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PRECAUTIONS
Precautions (Cont'd)
AT-7

IBefore assembly, apply a coat of recommended ATF to all
parts. Apply petroleum jelly to protect O-rings and seals, or
hold bearings and washers in place during assembly. Do not
use grease.
IExtreme care should be taken to avoid damage to O-rings,
seals and gaskets when assembling.
IReplace ATF cooler if excessive foreign material is found in oil
pan or clogging strainer. Refer to ªATF COOLER SERVICEº,
AT-9.
IAfter overhaul, refill the transmission with new ATF.
IWhen the A/T drain plug is removed, only some of the fluid is
drained. Old A/T fluid will remain in torque converter and ATF
cooling system.
Always follow the procedures when changing A/T fluid. Refer
to MA-21, ªChanging A/T Fluidº.
Service Notice or PrecautionsNBAT0004FAIL-SAFENBAT0004S01The TCM has an electronic Fail-Safe (limp home mode). This allows the vehicle to be driven even if a major
electrical input/output device circuit is damaged.
Under Fail-Safe, the vehicle always runs in third gear, even with a shift lever position of ª1º, ª2º or ªDº. The
customer may complain of sluggish or poor acceleration.
When the ignition key is turned ªONº following Fail-Safe operation, O/D OFF indicator lamp blinks for about
8 seconds. (For ªTCM SELF-DIAGNOSTIC PROCEDURE (No Tools)º, refer to AT-46.)
Fail-Safe may occur without electrical circuit damage if the vehicle is driven under extreme conditions (such
as excessive wheel spin followed by sudden braking). To recover normal shift pattern, turn the ignition key
ªOFFº for 5 seconds, then ªONº.
The blinking of the O/D OFF indicator lamp for about 8 seconds will appear only once and be cleared. The
customer may resume normal driving conditions.
Always follow the ªWORK FLOWº (Refer to AT-57).
The SELF-DIAGNOSIS results will be as follows:
The first SELF-DIAGNOSIS will indicate damage to the vehicle speed sensor or the revolution sensor.
During the next SELF-DIAGNOSIS, performed after checking the sensor, no damages will be indicated.
TORQUE CONVERTER SERVICENBAT0004S04The torque converter should be replaced under any of the following conditions:
IExternal leaks in the hub weld area.
IConverter hub is scored or damaged.
IConverter pilot is broken, damaged or fits poorly into crankshaft.
ISteel particles are found after flushing the cooler and cooler lines.
IPump is damaged or steel particles are found in the converter.
IVehicle has TCC shudder and/or no TCC apply. Replace only after all hydraulic and electrical diagnoses
have been made. (Converter clutch material may be glazed.)
IConverter is contaminated with engine coolant containing antifreeze.
IInternal failure of stator roller clutch.
IHeavy clutch debris due to overheating (blue converter).
ISteel particles or clutch lining material found in fluid filter or on magnet when no internal parts in unit are
worn or damaged Ð indicates that lining material came from converter.
The torque converter should not be replaced if:
IThe fluid has an odor, is discolored, and there is no evidence of metal or clutch facing particles.
PRECAUTIONS
Precautions (Cont'd)
AT-8

IThe threads in one or more of the converter bolt holes are damaged.
ITransmission failure did not display evidence of damaged or worn internal parts, steel particles or clutch
plate lining material in unit and inside the fluid filter.
IVehicle has been exposed to high mileage (only). The exception may be where the torque converter clutch
dampener plate lining has seen excess wear by vehicles operated in heavy and/or constant traffic, such
as taxi, delivery or police use.
ATF COOLER SERVICENBAT0004S02Replace ATF cooler if excessive foreign material is found in oil pan or clogging strainer.
Replace radiator lower tank (which includes ATF cooler) with a new one and flush cooler line using cleaning
solvent and compressed air. Refer to LC-19, ªREMOVAL AND INSTALLATIONº.
OBD-II SELF-DIAGNOSISNBAT0004S03IA/T self-diagnosis is performed by the TCM in combination with the ECM. The results can be read through
the blinking pattern of the O/D OFF indicator or the malfunction indicator lamp (MIL). Refer to the table on
AT-38 for the indicator used to display each self-diagnostic result.
IThe self-diagnostic results indicated by the MIL are automatically stored in both the ECM and TCM
memories.
Always perform the procedure ªHOW TO ERASE DTCº on AT-35 to complete the repair and avoid
unnecessary blinking of the MIL.
IThe following self-diagnostic items can be detected using ECM self-diagnostic results mode* only when
the O/D OFF indicator lamp does not indicate any malfunctions.
þ PNP switch
þ A/T 1st, 2nd, 3rd, or 4th gear function
þ A/T TCC S/V function (lock-up)
*: For details of OBD-II, refer to EC-59, ªIntroductionº.
ICertain systems and components, especially those related to OBD, may use the new style slide-
locking type harness connector. For description and how to disconnect, refer to EL-5, ªDescrip-
tionº.
Wiring Diagrams and Trouble DiagnosisNBAT0005When 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 diagnosis, refer to the following:
IGI-35, ªHOW TO FOLLOW TEST GROUP IN TROUBLE DIAGNOSISº.
IGI-24, ªHOW TO PERFORM EFFICIENT DIAGNOSIS FOR AN ELECTRICAL INCIDENTº.
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PRECAUTIONS
Service Notice or Precautions (Cont'd)
AT-9

Special Service ToolsNBAT0006The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here.
Tool number
(Kent-Moore No.)
Tool nameDescription
ST2505S001
(J34301-C)
Oil pressure gauge set
1 ST25051001
(Ð)
Oil pressure gauge
2 ST25052000
(Ð)
Hose
3 ST25053000
(Ð)
Joint pipe
4 ST25054000
(Ð)
Adapter
5 ST25055000
(Ð)
Adapter
NT097
Measuring line pressure
ST07870000
(J37068)
Transmission case stand
NT421
Disassembling and assembling A/T
a: 182 mm (7.17 in)
b: 282 mm (11.10 in)
c: 230 mm (9.06 in)
d: 100 mm (3.94 in)
KV31102100
(J37065)
Torque converter one-
way clutch check tool
NT098
Checking one-way clutch in torque converter
ST25850000
(J25721-A)
Sliding hammer
NT422
Removing oil pump assembly
a: 179 mm (7.05 in)
b: 70 mm (2.76 in)
c: 40 mm (1.57 in) dia.
d: M12 x 1.75P
KV31102400
(J34285 and J34285-87)
Clutch spring compres-
sor
NT423
Removing and installing clutch return springs
a: 320 mm (12.60 in)
b: 174 mm (6.85 in)
PREPARATION
Special Service Tools
AT-10

Shift MechanismNBAT0012The automatic transmission uses compact, dual planetary gear systems to improve power-transmission
efficiency, simplify construction and reduce weight.
It also employs an optimum shift control and superwide gear ratios. They improve starting performance and
acceleration during medium and high-speed operation.
Two one-way clutches are also employed: one is used for the forward clutch and the other for the low clutch.
These one-way clutches, combined with four accumulators, reduce shifting shock to a minimum.
CONSTRUCTIONNBAT0012S01
SAT509I
1. Torque converter clutch piston
2. Torque converter
3. Oil pump
4. Input shaft
5. Brake band
6. Reverse clutch
7. High clutch
8. Front pinion gear9. Front sun gear
10. Front internal gear
11. Front planetary carrier
12. Rear sun gear
13. Rear pinion gear
14. Rear internal gear
15. Rear planetary carrier
16. Forward clutch17. Forward one-way clutch
18. Overrun clutch
19. Low one-way clutch
20. Low & reverse brake
21. Parking pawl
22. Parking gear
23. Output shaft
FUNCTION OF CLUTCH AND BRAKENBAT0012S02
Clutch and brake components Abbr. Function
Reverse clutch6R/C To transmit input power to front sun gear9.
High clutch7H/C To transmit input power to front planetary carrier11.
Forward clutch16F/C To connect front planetary carrier11with forward one-way
clutch17.
Overrun clutch18O/C To connect front planetary carrier11with rear internal gear14.
Brake band5B/B To lock front sun gear9.
Forward one-way clutch17F/O.C When forward clutch16is engaged, to stop rear internal gear
14from rotating in opposite direction against engine revolution.
Low one-way clutch19L/O.C To stop front planetary carrier11from rotating in opposite direc-
tion against engine revolution.
Low & reverse brake20L & R/B To lock front planetary carrier11.
OVERALL SYSTEM
Shift Mechanism
AT-16

CLUTCH AND BAND CHARTNBAT0012S03
Shift positionReverse
clutchHigh
clutchFor-
ward
clutchOver-
run
clutchBand servoFor-
ward
one
-way
clutchLow
one-
way
clutchLow &
reverse
brakeLock-up Remarks
2nd
apply3rd
release4th
apply
PPARK
POSITION
RqqREVERSE
POSITION
NNEUTRAL
POSITION
D*41stq*1D B B
Automatic
shift
1k2k3
k4 2ndq*1AqB
3rdqq*1A *2C C B *5q
4thqC *3C Cqq
21stqDBBAutomatic
shift
1k2 2ndq*1AqB
11stqqBqLocks (held
stationary) in
1st speed
1g2 2ndqqqB
*1: Operates when overdrive control switch is being set in ªOFFº position.
*2: Oil pressure is applied to both 2nd ªapplyº side and 3rd ªreleaseº side of band servo piston. However, brake band does not contract
because oil pressure area on the ªreleaseº side is greater than that on the ªapplyº side.
*3: Oil pressure is applied to 4th ªapplyº side in condition *2 above, and brake band contracts.
*4: A/T will not shift to 4th when overdrive control switch is set in ªOFFº position.
*5: Operates when overdrive control switch is ªOFFº.
q: Operates.
A: Operates when throttle opening is less than 3/16, activating engine brake.
B: Operates during ªprogressiveº acceleration.
C: Operates but does not affect power transmission.
D: Operates when throttle opening is less than 3/16, but does not affect engine brake.
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OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-17

POWER TRANSMISSION=NBAT0012S04ªNº and ªPº PositionsNBAT0012S0401IªNº position
No control members operate. Power from the input shaft is not transmitted to the output shaft since the
clutch does not operate.
IªPº position
Similar to the ªNº position, no control members operate. The parking pawl interconnected with the select
lever engages with the parking gear to mechanically hold the output shaft so that the power train is locked.
SAT039J
OVERALL SYSTEM
Shift Mechanism (Cont'd)
AT-18