2001 INFINITI QX4 Engine control

Items Symptom Condition Diagnostic Item Reference Page
Slips/Will Not
EngageRaces extremely
fast or slips in
changing from D
4or D3to D1when
depressing pedal.ON vehicle1. Fluid level AT-59
2. Throttle position sensor (Adjustment) EC-174
3. Line pressure test AT-62
4. Line pressure solenoid valve AT-162
5. Control valve assembly AT-273
OFF vehicle6. Forward clutch AT-320
7. Forward one-way clutch AT-330
8. Low one-way clutch AT-328
Vehicle will not
run in any posi-
tion.ON vehicle1. Fluid level AT-59
2. Manual control linkage adjustment AT-276
3. Line pressure test AT-62
4. Line pressure solenoid valve AT-162
OFF vehicle5. Oil pump AT-297
6. High clutch AT-317
7. Brake band AT-333
8. Low & reverse brake AT-324
9. Torque converter AT-286
10. Parking pawl components AT-337
NOT USEDEngine cannot be
started in P and N
positions.
AT-221ON vehicle1. Ignition switch and starter EL-9, and SC-10
2. Manual control linkage adjustment AT-276
3. Park/neutral position (PNP) switch
adjustmentAT-276
Engine starts in
positions other
than P and N.
AT-221ON vehicle1. Manual control linkage adjustment AT-276
2. Park/neutral position (PNP) switch
adjustmentAT-276
Transmission
noise in P and N
positions.ON vehicle1. Fluid level AT-59
2. Line pressure test AT-62
3. Throttle position sensor (Adjustment) EC-174
4. Vehicle speed sensor´A/T (Revolution
sensor) and vehicle speed sensor´MTRAT- 111 , 1 9 7
5. Engine speed signal AT-116
OFF vehicle6. Oil pump AT-297
7. Torque converter AT-286
Vehicle moves
when changing
into P position or
parking gear does
not disengage
when shifted out
of P position.
AT-222ON vehicle 1. Manual control linkage adjustment AT-276
OFF vehicle 2. Parking pawl components AT-337
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Symptom Chart (Cont'd)
AT-88

Items Symptom Condition Diagnostic Item Reference Page
NOT USEDVehicle runs in N
position.
AT-223ON vehicle 1. Manual control linkage adjustment AT-276
OFF vehicle2. Forward clutch AT-320
3. Reverse clutch AT-314
4. Overrun clutch AT-320
Vehicle braked
when shifting into
R position.ON vehicle1. Fluid level AT-59
2. Manual control linkage adjustment AT-276
3. Line pressure test AT-62
4. Line pressure solenoid valve AT-162
5. Control valve assembly AT-273
OFF vehicle6. High clutch AT-317
7. Brake band AT-333
8. Forward clutch AT-320
9. Overrun clutch AT-320
Excessive creep. ON vehicle 1. Engine idling rpm EC-431
Engine stops
when shifting
lever into R, D, 2
and 1.ON vehicle1. Engine idling rpm EC-431
2. Torque converter clutch solenoid valve AT-148
3. Control valve assembly AT-273
OFF vehicle 4. Torque converter AT-286
Vehicle braked by
gear change from
D
1to D2.ON vehicle 1. Fluid level AT-59
OFF vehicle2. Reverse clutch AT-314
3. Low & reverse brake AT-324
4. High clutch AT-317
5. Low one-way clutch AT-328
Vehicle braked by
gear change from
D
2to D3.ON vehicle 1. Fluid level AT-59
OFF vehicle 2. Brake band AT-333
Vehicle braked by
gear change from
D
3to D4.ON vehicle 1. Fluid level AT-59
OFF vehicle2. Overrun clutch AT-320
3. Forward one-way clutch AT-330
4. Reverse clutch AT-314
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Symptom Chart (Cont'd)
AT-89

Items Symptom Condition Diagnostic Item Reference Page
NOT USEDMaximum speed
not attained.
Acceleration poor.ON vehicle1. Fluid level AT-59
2. Park/neutral position (PNP) switch
adjustmentAT-276
3. Shift solenoid valve A AT-168
4. Shift solenoid valve B AT-172
5. Control valve assembly AT-273
OFF vehicle6. Reverse clutch AT-314
7. High clutch AT-317
8. Brake band AT-333
9. Low & reverse brake AT-324
10. Oil pump AT-297
11. Torque converter AT-286
Transmission
noise in D, 2, 1
and R positions.ON vehicle 1. Fluid level AT-59
ON vehicle 2. Torque converter AT-286
Engine brake
does not operate
in ª1º position.
AT-252ON vehicle1. Park/neutral position (PNP) switch
adjustmentAT-276
2. Manual control linkage adjustment AT-276
3. Throttle position sensor (Adjustment) EC-174
4. Vehicle speed sensor´A/T (Revolution
sensor) and vehicle speed sensor´MTRAT- 111 , 1 9 7
5. Shift solenoid valve A AT-168
6. Control valve assembly AT-273
7. Overrun clutch solenoid valve AT-185
OFF vehicle8. Overrun clutch AT-320
9. Low & reverse brake AT-324
Transmission
overheats.ON vehicle1. Fluid level AT-59
2. Engine idling rpm EC-431
3. Throttle position sensor (Adjustment) EC-174
4. Line pressure test AT-62
5. Line pressure solenoid valve AT-162
6. Control valve assembly AT-273
OFF vehicle7. Oil pump AT-297
8. Reverse clutch AT-314
9. High clutch AT-317
10. Brake band AT-333
11. Forward clutch AT-320
12. Overrun clutch AT-320
13. Low & reverse brake AT-324
14. Torque converter AT-286
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Symptom Chart (Cont'd)
AT-90

Items Symptom Condition Diagnostic Item Reference Page
NOT USEDATF shoots out
during operation.
White smoke
emitted from
exhaust pipe dur-
ing operation.ON vehicle 1. Fluid level AT-59
OFF vehicle2. Reverse clutch AT-314
3. High clutch AT-317
4. Brake band AT-333
5. Forward clutch AT-320
6. Overrun clutch AT-320
7. Low & reverse brake AT-324
Offensive smell at
fluid charging
pipe.ON vehicle 1. Fluid level AT-59
OFF vehicle2. Torque converter AT-286
3. Oil pump AT-297
4. Reverse clutch AT-314
5. High clutch AT-317
6. Brake band AT-333
7. Forward clutch AT-320
8. Overrun clutch AT-320
9. Low & reverse brake AT-324
Engine is stopped
at R, D, 2 and 1
positions.ON vehicle1. Fluid level AT-59
2. Torque converter clutch solenoid valve AT-148
3. Shift solenoid valve B AT-172
4. Shift solenoid valve A AT-168
5. Control valve assembly AT-273
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Symptom Chart (Cont'd)
AT-91

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
13 GYO/D OFF indica-
tor lamp
When setting overdrive control switch in ªONº
position.Battery volt-
age
When setting overdrive control switch in
ªOFFº position.0V
14 Ð Ð Ð Ð
15 Ð Ð Ð Ð
16 OR/WClosed throttle
position switch
(in throttle posi-
tion switch)When releasing accelerator pedal after warm-
ing up engine.
Refer to ªPreparationº, ªTCM SELF-DIAG-
NOSTIC PROCEDURE (No Tools)º, AT-46.Battery volt-
age
When depressing accelerator pedal after
warming up engine.
Refer to ªPreparationº, ªTCM SELF-DIAG-
NOSTIC PROCEDURE (No Tools)º, AT-46.0V
17 OR/BWide open
throttle position
switch
(in throttle posi-
tion switch)When depressing accelerator pedal more than
half-way after warming up engine.Battery volt-
age
When releasing accelerator pedal after warm-
ing up engine.0V
18 B/YASCD cruise sig-
nal
When ASCD cruise is being performed.
(ªCRUISEº light comes on.)Battery volt-
age
When ASCD cruise is not being performed.
(ªCRUISEº light does not comes on.)0V
19 W/R Power source
Same as No. 10
20 L/BOverrun clutch
solenoid valve
When overrun clutch solenoid valve operates.Battery volt-
age
When overrun clutch solenoid valve does not
operate.0V
21 Ð Ð
ÐÐ
22 GYOverdrive control
switchWhen setting overdrive control switch in ªONº
positionBattery volt-
age
When setting overdrive control switch in
ªOFFº position0V
23 Ð Ð Ð Ð
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
TCM Terminals and Reference Value (Cont'd)
AT-93

Terminal
No.Wire color Item ConditionJudgement
standard
(Approx.)
39 W/BEngine speed
signal
Refer to EC-127, ªECM INSPECTION
TABLEº.Ð
40 W/LVehicle speed
sensor
When moving vehicle at 2 to 3 km/h (1 to 2
MPH) for1m(3ft)ormore.Voltage varies
between less
than 1.0V and
more than
4.5V.
41 PThrottle position
sensor
When depressing accelerator pedal slowly
after warming up engine.
(Voltage rises gradually in response to throttle
position.)Fully-closed
throttle:
0.5V - 0.7V
Fully-open
throttle:
4V
42 BThrottle position
sensor
(Ground)Ð0V
45 G/Y Stop lamp switchWhen depressing brake pedalBattery volt-
age
When releasing brake pedal 0V
46 WTransfer control
unitÐÐ
47 RA/T fluid tempera-
ture sensorWhen ATF temperature is 20ÉC (68ÉF). 1.5V
When ATF temperature is 80ÉC (176ÉF). 0.5V
48 B Ground
Ð0V
*1: These terminals are connected to the ECM.
*2: These terminals are connected to the Data link connector for CONSULT-II.
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
TCM Terminals and Reference Value (Cont'd)
AT-95

Diagnostic ProcedureNBAT0038
1 CHECK DTC WITH ECM
ICheck P code with CONSULT-II.
Turn ignition switch ªONº and select ªSELF-DIAG RESULTSº mode for ªENGINEº with CONSULT-II.
Refer to EC-74, ªDESCRIPTIONº.
OK or NG
OK (With CONSULT-II)©GO TO 2.
OK (Without CONSULT-
II)©GO TO 4.
NG©Check ignition signal circuit for engine control. Refer to EC-499, ªComponent Descrip-
tionº.
2 CHECK INPUT SIGNAL (WITH CONSULT-II)
With CONSULT-II
1. Start engine.
2. Select ªTCM INPUT SIGNALSº in ªDATA MONITORº mode for ªA/Tº with CONSULT-II.
3. Read out the value of ªENGINE SPEEDº.
Check engine speed changes according to throttle position.
SAT645J
Refer toEC-127, ªECM INSPECTION TABLEº.
Ye s©GO TO 5.
No©GO TO 3.
3 DETECT MALFUNCTIONING ITEM
Check the following items:
IHarness for short or open between TCM and ECM
IResistor
IIgnition coil
Refer to EC-499, ªComponent Descriptionº.
OK or NG
OK©GO TO 5.
NG©Repair or replace damaged parts.
DTC P0725 ENGINE SPEED SIGNAL
Diagnostic Procedure
AT-118

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