2001 INFINITI QX4 Engine control

2 JUDGEMENT PROCEDURE STEP 1
1. Turn ignition switch to ªOFFº position.
2. Push shift lock release button.
3. Move selector lever from ªPº to ªDº position.
4. Turn ignition switch to ªONº position. (Do not start engine.)
5. Depress and hold overdrive control switch in ªOFFº position (the O/D OFF indicator lamp will be ªONº) until directed to
release the switch. (If O/D OFF indicator lamp does not come on, go to step 5 on AT-257.)
6. Turn ignition switch to ªOFFº position.
SAT968I
7. Turn ignition switch to ªONº position (Do not start engine.).
8. Release the overdrive control switch (the O/D OFF indicator lamp will be ªOFFº).
9. Wait 2 seconds.
10. Move selector lever to ª2º position.
11. Depress and release the overdrive control switch (the O/D OFF indicator lamp will be ªONº).
12. Depress and hold the overdrive control switch (the O/D OFF indicator lamp will be ªOFFº) until directed to release the
switch.
SAT969I
©GO TO 3.
ON BOARD DIAGNOSTIC SYSTEM DESCRIPTION
Diagnostic Procedure Without CONSULT-II (Cont'd)
AT-48

SAT631IB
IntroductionNBAT0019
SAT632I
SEF234G
The TCM receives a signal from the vehicle speed sensor, throttle
position sensor or PNP switch and provides shift control or lock-up
control via A/T solenoid valves.
The TCM also communicates with the ECM by means of a signal
sent from sensing elements used with the OBD-related parts of the
A/T system for malfunction-diagnostic purposes. The TCM is
capable of diagnosing malfunctioning parts while the ECM can
store malfunctions in its memory.
Input and output signals must always be correct and stable in the
operation of the A/T system. The A/T system must be in good
operating condition and be free of valve seizure, solenoid valve
malfunction, etc.
It is much more difficult to diagnose a problem that occurs intermit-
tently rather than continuously. Most intermittent problems are
caused by poor electric connections or improper wiring. In this
case, careful checking of suspected circuits may help prevent the
replacement of good parts.
A visual check only may not find the cause of the problems. A road
test with CONSULT-II (or GST) or a circuit tester connected should
be performed. Follow the ªWork Flowº. Refer to AT-57.
Before undertaking actual checks, take a few minutes to talk with
a customer who approaches with a driveability complaint. The cus-
tomer can supply good information about such problems, espe-
cially intermittent ones. Find out what symptoms are present and
under what conditions they occur. A ªDiagnostic Worksheetº like the
example (AT-55) should be used.
Start your diagnosis by looking for ªconventionalº problems first.
This will help troubleshoot driveability problems on an electronically
controlled engine vehicle.
Also check related Service bulletins.GI
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TROUBLE DIAGNOSIS Ð INTRODUCTION
Introduction
AT-53

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

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

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

Symptom ChartNBAT0233Numbers are arranged in order of inspection.
Perform inspections starting with number one and work up.
Items Symptom Condition Diagnostic Item Reference Page
No Lock-up
Engagement/TCC
InoperativeTorque converter
is not locked up.ON vehicle1. Throttle position sensor (Adjustment) EC-174
2. Vehicle speed sensor´A/T (Revolution
sensor) and vehicle speed sensor´MTRAT- 111 , 1 9 7
3. Park/neutral position (PNP) switch
adjustmentAT-276
4. Engine speed signal AT-116
5. A/T fluid temperature sensor AT-105
6. Line pressure test AT-62
7. Torque converter clutch solenoid valve AT-148
8. Control valve assembly AT-273
OFF vehicle 9. Torque converter AT-286
Torque converter
clutch piston slip.ON vehicle1. Fluid level AT-59
2. Throttle position sensor (Adjustment) EC-174
3. Line pressure test AT-62
4. Torque converter clutch solenoid valve AT-148
5. Line pressure solenoid valve AT-162
6. Control valve assembly AT-273
OFF vehicle 7. Torque converter AT-286
Lock-up point is
extremely high or
low.
AT-245ON vehicle1. Throttle position sensor (Adjustment) EC-174
2. Vehicle speed sensor´A/T (Revolution
sensor) and vehicle speed sensor´MTRAT- 111 , 1 9 7
3. Torque converter clutch solenoid valve AT-148
4. Control valve assembly AT-273
Shift ShockSharp shock in
shifting from N to
D position.ON vehicle1. Engine idling rpm EC-431
2. Throttle position sensor (Adjustment) EC-174
3. Line pressure test AT-62
4. A/T fluid temperature sensor AT-105
5. Engine speed signal AT-116
6. Line pressure solenoid valve AT-162
7. Control valve assembly AT-273
8. Accumulator N-D AT-273
OFF vehicle9. Turbine revolution sensor EC-368
10. Forward clutch AT-320
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Symptom Chart
AT-81

Items Symptom Condition Diagnostic Item Reference Page
Improper Shift
TimingKickdown oper-
ates or engine
overruns when
depressing pedal
in D
4beyond kick-
down vehicle
speed limit.ON vehicle1. Vehicle speed sensor´A/T (Revolution
sensor) and vehicle speed sensor´MTRAT- 111 , 1 9 7
2. Throttle position sensor (Adjustment) EC-174
3. Shift solenoid valve A AT-168
4. Shift solenoid valve B AT-172
Gear change from
2
2to 23in 2 posi-
tion.ON vehicle1. Park/neutral position (PNP) switch
adjustmentAT-276
Gear change from
1
1to 12in 1 posi-
tion.ON vehicle1. Park/neutral position (PNP) switch
adjustmentAT-276
2. Manual control linkage adjustment AT-276
No Down ShiftFailure to change
gear from D
4to
D
3.ON vehicle1. Fluid level AT-59
2. Throttle position sensor (Adjustment) EC-174
3. Overrun clutch solenoid valve AT-185
4. Shift solenoid valve A AT-168
5. Line pressure solenoid valve AT-162
6. Control valve assembly AT-273
OFF vehicle7. Low & reverse brake AT-324
8. Overrun clutch AT-320
Failure to change
gear from D
3to
D
2or from D4to
D
2.ON vehicle1. Fluid level AT-59
2. Throttle position sensor (Adjustment) EC-174
3. Shift solenoid valve A AT-168
4. Shift solenoid valve B AT-172
5. Control valve assembly AT-273
OFF vehicle6. High clutch AT-317
7. Brake band AT-333
Failure to change
gear from D
2to
D
1or from D3to
D
1.ON vehicle1. Fluid level AT-59
2. Throttle position sensor (Adjustment) EC-174
3. Shift solenoid valve A AT-168
4. Shift solenoid valve B AT-172
5. Control valve assembly AT-273
OFF vehicle6. Low one-way clutch AT-328
7. High clutch AT-317
8. Brake band AT-333
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Symptom Chart (Cont'd)
AT-83