brake INFINITI QX4 2001 Factory User Guide

SAT007J
ILine pressure is increased to a maximum irrespective of the
throttle opening when fluid temperature drops to þ10ÉC (14ÉF).
This pressure rise is adopted to prevent a delay in clutch and
brake operation due to extreme drop of fluid viscosity at low
temperature.
SHIFT CONTROLNBAT0180S02The shift is regulated entirely by electronic control to accommodate
vehicle speed and varying engine operations. This is accomplished
by electrical signals transmitted by the revolution sensor and
throttle position sensor. This results in improved acceleration per-
formance and fuel economy.
SAT008J
Control of Shift Solenoid Valves A and BNBAT0180S0201The TCM activates shift solenoid valves A and B according to sig-
nals from the throttle position sensor and revolution sensor to
select the optimum gear position on the basis of the shift schedule
memorized in the TCM.
The shift solenoid valve performs simple ON-OFF operation. When
set to ªONº, the drain circuit closes and pilot pressure is applied to
the shift valve.
[Relation between shift solenoid valves A and B and gear positions]
Shift solenoid valveGear position
D
1,21,11D2,22,12D3D4(OD) N-P
A ON (Closed) OFF (Open) OFF (Open) ON (Closed) ON (Closed)
B ON (Closed) ON (Closed) OFF (Open) OFF (Open) ON (Closed)
Control of Shift Valves A and BNBAT0180S0202
SAT047J
OVERALL SYSTEM
Control Mechanism (Cont'd)
AT-28

Torque Converter Clutch Control Valve OperationNBAT0180S0303
SAT048J
Lock-up Released
The OFF-duration of the torque converter clutch solenoid valve is
long, and pilot pressure is high. The pilot pressure pushes the end
face of the torque converter clutch control valve in combination with
spring force to move the valve to the left. As a result, converter
pressure is applied to chamber A (torque converter clutch piston
release side). Accordingly, the torque converter clutch piston
remains unlocked.
Lock-up Applied
When the OFF-duration of the torque converter clutch solenoid
valve is short, pilot pressure drains and becomes low. Accordingly,
the control valve moves to the right by the pilot pressure of the
other circuit and converter pressure. As a result, converter pres-
sure is applied to chamber B, keeping the torque converter clutch
piston applied.
Also smooth lock-up is provided by transient application and
release of the lock-up.
OVERRUN CLUTCH CONTROL (ENGINE BRAKE
CONTROL)
NBAT0180S04Forward one-way clutch is used to reduce shifting shocks in down-
shifting operations. This clutch transmits engine torque to the
wheels. However, drive force from the wheels is not transmitted to
the engine because the one-way clutch rotates idle. This means the
engine brake is not effective.
The overrun clutch operates when the engine brake is needed.
Overrun Clutch Operating ConditionsNBAT0180S0401
Gear position Throttle opening
ªDº position D
1,D2,D3gear position
Less than 3/16
ª2º position 2
1,22gear position
ª1º position 1
1,12gear position At any position
SAT014J
OVERALL SYSTEM
Control Mechanism (Cont'd)
AT-30

SAT015J
Overrun Clutch Solenoid Valve ControlNBAT0180S0402The overrun clutch solenoid valve is operated by an ON-OFF sig-
nal transmitted by the TCM to provide overrun clutch control
(engine brake control).
When this solenoid valve is ªONº, the pilot pressure drain port
closes. When it is ªOFFº, the drain port opens.
During the solenoid valve ªONº pilot pressure is applied to the end
face of the overrun clutch control valve.
SAT049J
Overrun Clutch Control Valve OperationNBAT0180S0403When the solenoid valve is ªONº, pilot pressure A is applied to the
overrun clutch control valve. This pushes up the overrun clutch
control valve. The line pressure is then shut off so that the clutch
does not engage.
When the solenoid valve is ªOFFº, pilot pressure A is not gener-
ated. At this point, the overrun clutch control valve moves down-
ward by spring force. As a result, overrun clutch operation pressure
is provided by the overrun clutch reducing valve. This causes the
overrun clutch to engage.
In the ª1º position, the overrun clutch control valve remains pushed
down so that the overrun clutch is engaged at all times.
Control ValveNBAT0181FUNCTION OF CONTROL VALVENBAT0181S01
Valve name Function
IPressure regulator valve
IPressure regulator plug
IPressure regulator sleeve plugRegulate oil discharged from the oil pump to provide optimum line pressure for all
driving conditions.
Pressure modifier valve Used as a signal supplementary valve to the pressure regulator valve. Regulates
pressure-modifier pressure (signal pressure) which controls optimum line pressure for
all driving conditions.
Modifier accumulator piston Smooths hydraulic pressure regulated by the pressure modifier valve to prevent pul-
sations.
Pilot valve Regulates line pressure to maintain a constant pilot pressure level which controls
lock-up mechanism, overrun clutch, 3-2 timing required for shifting.
Accumulator control valve
Accumulator control sleeveRegulate accumulator back-pressure to pressure suited to driving conditions.
Manual valve Directs line pressure to oil circuits corresponding to select positions.
Hydraulic pressure drains when the shift lever is in Neutral.
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OVERALL SYSTEM
Control Mechanism (Cont'd)
AT-31

Valve name Function
Shift valve A Simultaneously switches three oil circuits using output pressure of shift solenoid valve
A to meet driving conditions (vehicle speed, throttle opening, etc.).
Provides automatic downshifting and up-shifting (1st,2nd,3rd,4th gears/4th
,3rd,2nd,1st gears) in combination with shift valve B.
Shift valve B Simultaneously switches three oil circuits using output pressure of shift solenoid valve
B in relation to driving conditions (vehicle speed, throttle opening, etc.).
Provides automatic downshifting and up-shifting (1st,2nd,3rd,4th gears/4th
,3rd,2nd,1st gears) in combination with shift valve A.
Shuttle shift valve S Switches hydraulic circuits to provide 3-2 timing control and overrun clutch control in
relation to the throttle opening.
Inactivates the overrun clutch to prevent interlocking in 4th gear when the throttle is
wide open.
Overrun clutch control valve Switches hydraulic circuits to prevent engagement of the overrun clutch simulta-
neously with application of the brake band in 4th gear. (Interlocking occurs if the
overrun clutch engages during D
4gear operation.)
4-2 relay valve Memorizes that the transmission is in 4th gear. Prevents the transmission from down-
shifting from 4th gear to 3rd and then to 2nd in combination with 4-2 sequence valve
and shift valves A and B when downshifting from 4th to 2nd gear.
4-2 sequence valve Prevents band servo pressure from draining before high clutch operating pressure
and band servo releasing pressure drain (from the same circuit) during downshifting
from 4th to 2nd gear.
Servo charger valve An accumulator and a one-way orifice are used in the 2nd gear band servo oil circuit
to dampen shifting shock when shifting from 1st to 2nd gear.
To maintain adequate flow rate when downshifting from 4th or 3rd gear to 2nd gear,
the servo charger valve directs 2nd gear band servo hydraulic pressure to the circuit
without going through the one-way orifice when downshifting from 3rd or a higher
gear.
3-2 timing valve Prevents a late operation of the brake band when shifting selector lever from ªDº to
ª1º or ª2º position while driving in D
3.
ª1º reducing valve Reduces low & reverse brake pressure to dampen engine-brake shock when down-
shifting from the ª1º position 2nd gear to 1st gear.
Overrun clutch reducing valve Reduces oil pressure directed to the overrun clutch and prevents engine-brake shock.
In ª1º and ª2º positions, line pressure acts on the overrun clutch reducing valve to
increase the pressure-regulating point, with resultant engine brake capability.
Torque converter relief valve Prevents an excessive rise in torque converter pressure.
Torque converter clutch control valve,
torque converter clutch control plug and
torque converter clutch control sleeveActivate or inactivate the lock-up function.
Also provide smooth lock-up through transient application and release of the lock-up
system.
Shuttle shift valve D Switches hydraulic circuits so that output pressure of the torque converter clutch sole-
noid valve acts on the lock-up valve in the ªDº position of 2nd, 3rd and 4th gears. (In
the ªDº position 1st gear, lock-up is inhibited.)
ILock-up control is not affected in ªDº position 2nd, 3rd or 4th gears, unless output
pressure of the torque converter clutch solenoid valve is generated by a signal
from the control unit.
OVERALL SYSTEM
Control Valve (Cont'd)
AT-32

Item DisplayMonitor item
Description Remarks
TCM input
signalsMain sig-
nals
1 position switch 1 POSITION SW
[ON/OFF]
XÐION/OFF status, com-
puted from signal of 1
position SW, is dis-
played.
ASCD cruise signal ASCD-CRUISE
[ON/OFF]
XÐIStatus of ASCD cruise
signal is displayed.
ON ... Cruising state
OFF ... Normal running
stateIThis is displayed even
when no ASCD is
mounted.
ASCD OD cut signal ASCD-OD CUT
[ON/OFF]
XÐIStatus of ASCD OD
release signal is dis-
played.
ON ... OD released
OFF ... OD not releasedIThis is displayed even
when no ASCD is
mounted.
Kickdown switch KICKDOWN SW
[ON/OFF]
XÐION/OFF status, com-
puted from signal of
kickdown SW, is dis-
played.IThis is displayed even
when no kickdown
switch is equipped.
Closed throttle position
switchCLOSED
THL/SW
[ON/OFF]XÐION/OFF status, com-
puted from signal of
closed throttle position
SW, is displayed.
Wide open throttle position
switchW/O THRL/P-SW
[ON/OFF]
XÐION/OFF status, com-
puted from signal of
wide open throttle posi-
tion SW, is displayed.
Stop lamp switch BRAKE SW
[ON/OFF]
XÐION/OFF status is dis-
played.
ON ... Brake pedal is
depressed.
OFF ... Brake pedal is
released.
Gear position GEAR
ÐXIGear position data used
for computation by TCM,
is displayed.
Selector lever position SLCT LVR POSI
ÐXISelector lever position
data, used for computa-
tion by TCM, is dis-
played.IA specific value used for
control is displayed if
fail-safe is activated due
to error.
Vehicle speed VEHICLE
SPEED
[km/h] or [mph]ÐXIVehicle speed data,
used for computation by
TCM, is displayed.
Throttle position THROTTLE
POSI
[/8]ÐXIThrottle position data,
used for computation by
TCM, is displayed.IA specific value used for
control is displayed if
fail-safe is activated due
to error.
Line pressure duty LINE PRES DTY
[%]
ÐXIControl value of line
pressure solenoid valve,
computed by TCM from
each input signal, is dis-
played.GI
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ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
CONSULT-II (Cont'd)
AT-41

Diagnostic Worksheet=NBAT0019S0102
1.lRead the Fail-safe Remarks and listen to customer complaints. AT-8
2.lCHECK A/T FLUIDAT-59
lLeakage (Follow specified procedure)
lFluid condition
lFluid level
3. Perform STALL TEST and LINE PRESSURE TEST. AT-59, AT-62
lStall test Ð Mark possible damaged components/others.
lTorque converter one-way clutch
lReverse clutch
lForward clutch
lOverrun clutch
lForward one-way clutchlLow & reverse brake
lLow one-way clutch
lEngine
lLine pressure is low
lClutches and brakes except high clutch and
brake band are OK
lPressure test Ð Suspected parts:
4.lPerform all ROAD TEST and mark required procedures. AT-63
4-1. Check before engine is started.AT-64
lSELF-DIAGNOSTIC PROCEDURE - Mark detected items.
lDTC P0705 PNP switch, AT-99.
lDTC P0710 A/T fluid temperature sensor, AT-105.
lDTC P0720 Vehicle speed sensor´A/T (Revolution sensor), AT-111.
lDTC P0725 Engine speed signal, AT-116.
lDTC P0740 Torque converter clutch solenoid valve, AT-148.
lDTC P0745 Line pressure solenoid valve, AT-162.
lDTC P0750 Shift solenoid valve A, AT-168.
lDTC P0755 Shift solenoid valve B, AT-172.
lDTC P1705 Throttle position sensor, AT-176.
lDTC P1760 Overrun clutch solenoid valve, AT-185.
lDTC BATT/FLUID TEMP SEN (A/T fluid temperature sensor and TCM power source), AT-190.
lDTC Vehicle speed sensor´MTR, AT-197.
lDTC Turbine revolution sensor, AT-202.
lDTC A/T communication line, AT-207.
lDTC Control unit (RAM), control unit (ROM), AT-211.
lDTC Control unit (EEP ROM), AT-213.
lPNP, overdrive control and throttle position switches, AT-257.
lBattery
lOthers
4-2. Check at idleAT-66
l1. O/D OFF Indicator Lamp Does Not Come On, AT-218.
l2. Engine Cannot Be Started In ªPº And ªNº Position, AT-221.
l3. In ªPº Position, Vehicle Moves Forward Or Backward When Pushed, AT-222.
l4. In ªNº Position, Vehicle Moves, AT-223.
l5. Large Shock. ªNº,ªRº Position, AT-225.
l6. Vehicle Does Not Creep Backward In ªRº Position, AT-227.
l7. Vehicle Does Not Creep Forward In ªDº, ª2º Or ª1º Position, AT-230.GI
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TROUBLE DIAGNOSIS Ð INTRODUCTION
Introduction (Cont'd)
AT-55

4. 4-3. Cruise testAT-67
AT-71
Part-1
l8. Vehicle Cannot Be Started From D
1, AT-233.
l9. A/T Does Not Shift: D
1,D2Or Does Not Kickdown: D4,D2, AT-236.
l10. A/T Does Not Shift: D
2,D3, AT-239.
l11. A/T Does Not Shift: D
3,D4, AT-242.
l12. A/T Does Not Perform Lock-up, AT-245.
l13. A/T Does Not Hold Lock-up Condition, AT-247.
l14. Lock-up Is Not Released, AT-249.
l15. Engine Speed Does Not Return To Idle (Light Braking D
4,D3), AT-250.
Part-2AT-75
l16. Vehicle Does Not Start From D
1, AT-252.
l9. A/T Does Not Shift: D
1,D2Or Does Not Kickdown: D4,D2, AT-236.
l10. A/T Does Not Shift: D
2,D3, AT-239.
l11. A/T Does Not Shift: D
3,D4, AT-242.
Part-3AT-77
l17. A/T Does Not Shift: D
4,D3When Overdrive Control Switch ªONº,ªOFFº, AT-253
l15. Engine Speed Does Not Return To Idle (Engine Brake In D
3), AT-250.
l18. A/T Does Not Shift: D
3,22, When Selector Lever ªDº,ª2º Position, AT-254.
l15. Engine Speed Does Not Return To Idle (Engine Brake In 2
2), AT-250.
l19. A/T Does Not Shift: 2
2,11, When Selector Lever ª2º,ª1º Position, AT-255.
l20. Vehicle Does Not Decelerate By Engine Brake, AT-256.
lSELF-DIAGNOSTIC PROCEDURE Ð Mark detected items.
lDTC P0705 PNP switch, AT-99.
lDTC P0710 A/T fluid temperature sensor, AT-105.
lDTC P0720 Vehicle speed sensor´A/T (Revolution sensor), AT-111.
lDTC P0725 Engine speed signal, AT-116.
lDTC P0740 Torque converter clutch solenoid valve, AT-148.
lDTC P0745 Line pressure solenoid valve, AT-162.
lDTC P0750 Shift solenoid valve A, AT-168.
lDTC P0755 Shift solenoid valve B, AT-172.
lDTC P1705 Throttle position sensor, AT-176.
lDTC P1760 Overrun clutch solenoid valve, AT-185.
lDTC BATT/FLUID TEMP SEN (A/T fluid temperature sensor and TCM power source), AT-190.
lDTC Vehicle speed sensor´MTR, AT-197.
lDTC Turbine revolution sensor, AT-202.
lDTC A/T communication line, AT-207.
lDTC Control unit (RAM), control unit (ROM), AT-211.
lDTC Control unit (EEP ROM), AT-213.
lPNP, overdrive control and throttle position switches, AT-257.
lBattery
lOthers
5.lFor self-diagnosis NG items, inspect each component. Repair or replace the damaged parts. AT-38
6.lPerform all ROAD TEST and re-mark required procedures. AT-63
7.lPerform DTC CONFIRMATION PROCEDURE for following MIL indicating items and check out NG items.
Refer to EC-60, ªEmission-related Diagnostic Informationº.EC-60
lDTC (P0731, 1103) A/T 1st gear function, AT-120.
lDTC (P0732, 1104) A/T 2nd gear function, AT-126.
lDTC (P0733, 1105) A/T 3rd gear function, AT-132.
lDTC (P0734, 1106) A/T 4th gear function, AT-138.
lDTC (P0744, 1107) A/T TCC S/V function (lock-up), AT-153.
8.lPerform the Diagnostic Procedures for all remaining items marked NG. Repair or replace the damaged
parts.
Refer to the Symptom Chart when you perform the procedures. (The chart also shows some other possible
symptoms and the component inspection orders.)AT-92
AT-97
9.lErase DTC from TCM and ECM memories. AT-35
TROUBLE DIAGNOSIS Ð INTRODUCTION
Introduction (Cont'd)
AT-56

A/T Fluid CheckNBAT0021FLUID LEAKAGE CHECKNBAT0021S011. Clean area suspected of leaking. Ð for example, mating sur-
face of converter housing and transmission case.
2. Start engine, apply foot brake, place selector lever in ªDº posi-
tion and wait a few minutes.
3. Stop engine.
4. Check for fresh leakage.
SAT638A
FLUID CONDITION CHECKNBAT0021S02
Fluid color Suspected problem
Dark or black with burned odor Wear of frictional material
Milky pinkWater contamination Ð Road water
entering through filler tube or breather
Varnished fluid, light to dark brown
and tackyOxidation Ð Over or under filling, Ð
Overheating
FLUID LEVEL CHECKNBAT0021S03Refer to MA-21, ªChecking A/T Fluidº.
SAT647B
Stall TestNBAT0022STALL TEST PROCEDURENBAT0022S011. Check A/T fluid and engine oil levels. If necessary, add fluid
and oil.
2. Drive vehicle for approx. 10 minutes or until fluid and oil reach
operating temperature.
ATF operating temperature:
50 - 80ÉC (122 - 176ÉF)
SAT513G
3. Set parking brake and block wheels.
4. Install a tachometer where it can be seen by driver during test.
IIt is good practice to put a mark on point of specified
engine rpm on indicator.
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TROUBLE DIAGNOSIS Ð BASIC INSPECTION
A/T Fluid Check
AT-59

SAT514G
5. Start engine, apply foot brake, and place selector lever in ªDº
position.
6. Accelerate to wide open throttle gradually while applying foot
brake.
7. Quickly note the engine stall revolution and immediately
release throttle.
IDuring test, never hold throttle wide open for more than 5
seconds.
Stall revolution:
Refer to SDS, AT-356.
SAT771B
8. Move selector lever to ªNº position.
9. Cool off ATF.
IRun engine at idle for at least one minute.
10. Repeat steps 5 through 9 with selector lever in ª2º, ª1º and ªRº
positions.
JUDGEMENT OF STALL TESTNBAT0022S02The test result and possible damaged components relating to each
result are shown in the illustration. In order to pinpoint the possible
damaged components, refer to ªWork Flowº, AT-57.
NOTE:
Stall revolution is too high in ªDº or ª2º position:
ISlippage occurs in 1st gear but not in 2nd and 3rd gears. .....
Low one-way clutch slippage
ISlippage occurs at the following gears:
1st through 3rd gears in ªDº position and engine brake func-
tions.
1st and 2nd gears in ª2º position and engine brake functions
with accelerator pedal released (fully closed throttle). ..... For-
ward clutch or forward one-way clutch slippage
Stall revolution is too high in ªRº position:
IEngine brake does not function in ª1º position. ..... Low &
reverse brake slippage
IEngine brake functions in ª1º position. ..... Reverse clutch slip-
page
Stall revolution within specifications:
IVehicle does not achieve speed of more than 80 km/h (50
MPH). ..... One-way clutch seizure in torque converter housing
CAUTION:
Be careful since automatic fluid temperature increases abnor-
mally.
ISlippage occurs in 3rd and 4th gears in ªDº position. ..... High
clutch slippage
ISlippage occurs in 2nd and 4th gear in ªDº position. ..... Brake
band slippage
Stall revolution less than specifications:
IPoor acceleration during starts. ..... One-way clutch seizure in
torque converter
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Stall Test (Cont'd)
AT-60

SAT209GA
Line Pressure TestNBAT0023ILocation of line pressure test ports.
IAlways replace line pressure plugs as they are self-seal-
ing bolts.
SAT647B
LINE PRESSURE TEST PROCEDURENBAT0023S011. Check A/T fluid and engine oil levels. If necessary, add fluid
and oil.
2. Drive vehicle for approx. 10 minutes or until fluid and oil reach
operating temperature.
ATF operating temperature:
50 - 80ÉC (122 - 176ÉF)
SAT518GB
SAT519GB
3. Install pressure gauge to corresponding line pressure port.
SAT513G
4. Set parking brake and block wheels.
IContinue to depress brake pedal fully while line pressure
test is being performed at stall speed.
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Line Pressure Test
AT-62