2001 INFINITI QX4 check engine

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

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

SAT493G
5. Start engine and measure line pressure at idle and stall speed.
IWhen measuring line pressure at stall speed, follow the
stall test procedure.
Line pressure:
Refer to SDS, AT-356.
JUDGEMENT OF LINE PRESSURE TESTNBAT0023S02
Judgement Suspected parts
At idleLine pressure is low in all posi-
tions.IOil pump wear
IControl piston damage
IPressure regulator valve or plug sticking
ISpring for pressure regulator valve damaged
IFluid pressure leakage between oil strainer and pressure regulator valve
IClogged strainer
Line pressure is low in particu-
lar position.IFluid pressure leakage between manual valve and particular clutch
IFor example, line pressure is:
Ð Low in ªRº and ª1º positions, but
Ð Normal in ªDº and ª2º positions.
Then, fluid leakage exists at or around low and reverse brake circuit.
Refer to ªCLUTCH AND BAND CHARTº, AT-17.
Line pressure is high.IMal-adjustment of throttle position sensor
IFluid temperature sensor damaged
ILine pressure solenoid valve sticking
IShort circuit of line pressure solenoid valve circuit
IPressure modifier valve sticking
IPressure regulator valve or plug sticking
IOpen in dropping resistor circuit
At stall speedLine pressure is low.IMal-adjustment of throttle position sensor
ILine pressure solenoid valve sticking
IShort circuit of line pressure solenoid valve circuit
IPressure regulator valve or plug sticking
IPressure modifier valve sticking
IPilot valve sticking
SAT786A
Road TestNBAT0024DESCRIPTIONNBAT0024S01IThe purpose of the test is to determine overall performance of
A/T and analyze causes of problems.
IThe road test consists of the following three parts:
1. Check before engine is started
2. Check at idle
3. Cruise test
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TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Line Pressure Test (Cont'd)
AT-63

SAT496G
IBefore road test, familiarize yourself with all test procedures
and items to check.
IConduct tests on all items until specified symptom is found.
Troubleshoot items which check out No Good after road test.
Refer to ªON BOARD DIAGNOSTIC SYSTEM DESCRIP-
TIONº and ªTROUBLE DIAGNOSES FOR SYMPTOMSº,
AT-33 - AT-50 and AT-215 - AT-257.
1. CHECK BEFORE ENGINE IS STARTEDNBAT0024S02
1 CHECK O/D OFF INDICATOR LAMP
1. Park vehicle on flat surface.
2. Move selector lever to ªPº position.
3. Turn ignition switch to ªOFFº position.
Wait at least 5 seconds.
SAT967I
4. Turn ignition switch to ªONº position. (Do not start engine.)
5. Does O/D OFF indicator lamp come on for about 2 seconds?
SAT133K
YesorNo
Ye s©GO TO 2.
No©Go to ª1. O/D OFF Indicator Lamp Does Not Come Onº, AT-218.
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Road Test (Cont'd)
AT-64

2. CHECK AT IDLE=NBAT0024S03
1 CHECK ENGINE START
1. Park vehicle on flat surface.
2. Turn ignition switch to ªOFFº position.
3. Move selector lever to ªPº or ªNº position.
4. Turn ignition switch to start position.
5. Is engine started?
YesorNo
Ye s©GO TO 2.
No©Go to ª2. Engine Cannot Be Started In ªPº and ªNº Positionº, AT-221.
2 CHECK ENGINE START
1. Turn ignition switch to ªOFFº position.
2. Move selector lever to ªDº, ª1º, ª2º or ªRº position.
3. Turn ignition switch to start position.
4. Is engine started?
YesorNo
Ye s©Go to ª2. Engine Cannot Be Started In ªPº and ªNº Positionº, AT-221.
No©GO TO 3.
3 CHECK VEHICLE MOVE
1. Turn ignition switch to ªOFFº position.
2. Move selector lever to ªPº position.
3. Release parking brake.
4. Push vehicle forward or backward.
5. Does vehicle move when it is pushed forward or backward?
SAT796A
YesorNo
Ye s©Go to ª3. In ªPº Position, Vehicle Moves Forward Or Backward When Pushedº, AT-222.
No©GO TO 4.
4 CHECK VEHICLE MOVE
1. Apply parking brake.
2. Move selector lever to ªNº position.
3. Turn ignition switch to ªSTARTº position and start engine.
4. Release parking brake.
5. Does vehicle move forward or backward?
YesorNo
Ye s©Go to ª4. In ªNº Position, Vehicle Movesº, AT-223.
No©GO TO 5.
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Road Test (Cont'd)
AT-66

Cruise Test Ð Part 1=NBAT0024S0404
1 CHECK STARTING GEAR (D1) POSITION
1. Drive vehicle for approx. 10 minutes to warm engine oil and ATF up to operating temperature.
ATF operating temperature:
50 - 80ÉC (122 - 176ÉF)
2. Park vehicle on flat surface.
3. Set overdrive control switch to ªONº position.
4. Move selector lever to ªPº position.
SAT001J
5. Start engine.
6. Move selector lever to ªDº position.
SAT952I
7. Accelerate vehicle by constantly depressing accelerator pedal halfway.
SAT953I
8. Does vehicle start from D1?
Read gear position.
YesorNo
Ye s©GO TO 2.
No©Go to ª8. Vehicle Cannot Be Started From D
1º, AT-233.
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TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Road Test (Cont'd)
AT-71

7 CHECK LOCK-UP OFF (D4L/U TO D4)
1. Release accelerator pedal.
2. Is lock-up released when accelerator pedal is released?
SAT958I
YesorNo
Ye s©GO TO 8.
No©Go to ª14. Lock-up Is Not Releasedº, AT-249.
8 CHECK SHIFT DOWN (D4TO D3)
1. Decelerate vehicle by applying foot brake lightly.
2. Does engine speed return to idle smoothly when A/T is shifted from D
4to D3?
Read gear position and engine speed.
SAT959I
YesorNo
Ye s©1. Stop vehicle.
2. Go to ªCruise test Ð Part 2º, AT-75.
No©Go to ª15. Engine Speed Does Not Return To Idle (Light Braking D
4,D3)º, AT-250.
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Road Test (Cont'd)
AT-74

3 CHECK SHIFT UP (D2TO D3)
Does A/T shift from D2to D3at the specified speed?
Read gear position, throttle position and vehicle speed.
Specified speed when shifting from D
2to D3:
Refer to Shift schedule, AT-356.
SAT960I
YesorNo
Ye s©GO TO 4.
No©Go to ª10. A/T Does Not Shift: D
2,D3º, AT-239.
4 CHECK SHIFT UP (D3TO D4) AND ENGINE BRAKE
Release accelerator pedal after shifting from D2to D3.
Does A/T shift from D
3to D4and does vehicle decelerate by engine brake?
Read gear position, throttle position and vehicle speed.
SAT405H
YesorNo
Ye s©1. Stop vehicle.
2. Go to ªCruise test Ð Part 3º, AT-77.
No©Go to ª11. A/T Does Not Shift: D
3,D4º, AT-242.
TROUBLE DIAGNOSIS Ð BASIC INSPECTION
Road Test (Cont'd)
AT-76