2001 INFINITI QX4 lock

DescriptionNBAT0048IThis 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
fourth gear position or the torque converter clutch does not
lock up as instructed by the TCM. This is not caused by elec-
trical malfunction (circuits open or shorted) but by mechanical
malfunction such as control valve sticking, improper solenoid
valve operation, malfunctioning oil pump or torque converter
clutch, etc.
CONSULT-II REFERENCE VALUE IN DATA MONITOR
MODE
NBAT0048S04Remarks: Specification data are reference values.
Monitor item Condition Specification
Line pressure solenoid valve
dutySmall throttle opening (Low line pressure)
"
Large throttle opening (High line pressure)Approximately 24%
"
Approximately 95%
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 VALUENBAT0048S02Remarks: Specification data are reference values.
Terminal
No.Wire color Item ConditionJudgement
standard
(Approx.)
1GYLine pressure
solenoid valve
When releasing accelerator pedal after warm-
ing up engine.1.5 - 3.0V
When depressing accelerator pedal fully after
warming up engine.0V
2 BR/YLine pressure
solenoid valve
(with dropping
resistor)When releasing accelerator pedal after warm-
ing up engine.5 - 14V
When depressing accelerator pedal fully after
warming up engine.0V
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
DTC P0734 IMPROPER SHIFTING TO 4TH GEAR POSITION
Description
AT-138

SAT342HA
DescriptionNBAT0051The torque converter clutch solenoid valve is activated, with the
gear in ªD
4º, by the TCM in response to signals sent from the
vehicle speed and throttle position sensors. Lock-up piston opera-
tion will then be controlled.
Lock-up operation, however, is prohibited when A/T fluid tempera-
ture is too low.
When the accelerator pedal is depressed (less than 2/8) in lock-up
condition, the engine speed should not change abruptly. If there is
a big jump in engine speed, there is no lock-up.
CONSULT-II REFERENCE VALUE IN DATA MONITOR
MODE
NBAT0051S02Remarks: Specification data are reference values.
Monitor item Condition Specification
Torque converter clutch
solenoid valve dutyLock-up ªOFFº
"
Lock-up ªONºApproximately 4%
"
Approximately 94%
TCM TERMINALS AND REFERENCE VALUENBAT0051S03Remarks: Specification data are reference values.
Terminal
No.Wire color Item ConditionJudgement
standard
(Approx.)
3 G/ORTorque converter
clutch solenoid
valve
When A/T performs lock-up. 8 - 15V
When A/T does not perform lock-up. 0V
ON BOARD DIAGNOSIS LOGICNBAT0051S04
Diagnostic trouble code Malfunction is detected when ... Check item (Possible cause)
: TCC SOLENOID/CIRC TCM detects an improper voltage drop
when it tires to operate the solenoid
valve.IHarness or connectors
(The solenoid circuit is open or shorted.)
ITorque converter clutch solenoid valve
: P0740
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
Description
AT-148

DescriptionNBAT0054IThis 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
fourth gear position or the torque converter clutch does not
lock up as instructed by the TCM. This is not caused by elec-
trical malfunction (circuits open or shorted) but by mechanical
malfunction such as control valve sticking, improper solenoid
valve operation, malfunctioning oil pump or torque converter
clutch, etc.
CONSULT-II REFERENCE VALUE IN DATA MONITOR
MODE
NBAT0054S02Remarks: Specification data are reference values.
Monitor item Condition Specification
Torque converter clutch
solenoid valve dutyLock-up ªOFFº
"
Lock-up ªONºApproximately 4%
"
Approximately 94%
Line pressure solenoid
valve dutySmall throttle opening (Low line pressure)
"
Large throttle opening (High line pressure)Approximately 24%
"
Approximately 95%
TCM TERMINALS AND REFERENCE VALUENBAT0054S03Remarks: Specification data are reference values.
Terminal
No.Wire color Item ConditionJudgement
standard
(Approx.)
1GYLine pressure
solenoid valve
When releasing accelerator pedal after warm-
ing up engine.1.5 - 3.0V
When depressing accelerator pedal fully after
warming up engine.0V
2 BR/YLine pressure
solenoid valve
(with dropping
resistor)When releasing accelerator pedal after warm-
ing up engine.5 - 14V
When depressing accelerator pedal fully after
warming up engine.0V
3 G/ORTorque converter
clutch solenoid
valve
When A/T performs lock-up. 8 - 15V
When A/T does not perform lock- up. 0V
ON BOARD DIAGNOSIS LOGICNBAT0054S04This 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 much lower than the position (4th)
supposed by TCM, the slip ratio will be much less than normal. In
case the ratio does not reach the specified value, TCM judges this
diagnosis malfunction.
This malfunction will be caused when shift solenoid valve B is stuck
closed.
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0744 IMPROPER LOCK-UP OPERATION
Description
AT-153

Gear position supposed by TCM 1 2 3 4
In case of gear position with no malfunctions 1 2 3 4
In case of gear position with shift solenoid valve B stuck closed 1 2 2 1*
*: P0744 is detected.
Diagnostic trouble code Malfunction is detected when ... Check item (Possible cause)
: A/T TCC S/V FNCTN
A/T cannot perform lock-up even if elec-
trical circuit is good.ILine pressure solenoid valve
ITorque converter clutch solenoid valve
IEach clutch
IHydraulic control circuit
: P0744
SAT014K
SAT971J
DIAGNOSTIC TROUBLE CODE (DTC) CONFIRMATION
PROCEDURE
NBAT0054S01CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If ªDIAGNOSTIC TROUBLE CODE CONFIRMATION PROCE-
DUREº has been previously conducted, always turn ignition
switch ªOFFº and wait at least 5 seconds before conducting
the next test.
After the repair, perform the following procedure to confirm the
malfunction is eliminated.
With CONSULT-II
1) Start engine and select ªDATA MONITORº mode for ªA/Tº with
CONSULT-II.
2) Make sure that output voltage of A/T fluid temperature sensor
is within the range below.
FLUID TEMP SEN: 0.4 - 1.5V
If out of range, drive the vehicle to decrease the voltage (warm
up the fluid) or stop engine to increase the voltage (cool down
the fluid).
3) Select ªTCC S/V FNCTN P0744º of ªDTC WORK SUPPORTº
mode for ªA/Tº with CONSULT-II and touch ªSTARTº.
SAT021J
4) Accelerate vehicle to more than 67 to 100 km/h (42 to 62 MPH)
and maintain the following condition continuously until ªTEST-
INGº has turned to ªCOMPLETEDº. (It will take approximately
30 seconds after ªTESTINGº shows.)
THROTTLE POSI: 1.0/8 - 2.0/8 (at all times during step 4)
Selector lever: D position (OD ªONº)
TCC S/V DUTY: More than 94%
VHCL/S SE´A/T: Constant speed of more than 67 to 100
km/h (42 to 62 MPH)
ICheck that ªGEARº shows ª4º.
IFor shift schedule, refer to SDS, AT-356.
DTC P0744 IMPROPER LOCK-UP OPERATION
Description (Cont'd)
AT-154

IIf ªTESTINGº does not appear on CONSULT-II for a long
time, select ªSELF-DIAG RESULTSº. In case a 1st trip DTC
other than P0744 is shown, refer to applicable ªTROUBLE
DIAGNOSIS FOR DTCº.
5) Make sure that ªOKº is displayed. (If ªNGº is displayed, refer
to ªDIAGNOSTIC PROCEDUREº.)
Refer to ªDIAGNOSTIC PROCEDUREº, AT-157.
Refer to shift schedule, AT-356.
With GST
Follow the procedure ªWith CONSULT-IIº.
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0744 IMPROPER LOCK-UP OPERATION
Description (Cont'd)
AT-155

Wiring Diagram Ð AT Ð TCCSIGNBAT0195
MAT913A
DTC P0744 IMPROPER LOCK-UP OPERATION
Wiring Diagram Ð AT Ð TCCSIG
AT-156

Diagnostic Procedure=NBAT0055
1 CHECK SHIFT UP (D3TO D4)
During ªCruise test þ Part 1º, AT-71.
Does A/T shift from D
3to D4at the specified speed?
SAT988H
YesorNo
Ye s©IGO TO 10.
IAnd check for proper lock-up.
No©GO TO 2.
2 CHECK LINE PRESSURE
Perform line pressure test. Refer to AT-62.
OK or NG
OK©GO TO 3.
NG©GO TO 6.
3 CHECK CONTROL VALVE
1. Disassemble control valve assembly. Refer to AT-301.
2. Check to ensure that:
IValve, sleeve and plug slide along valve bore under their own weight.
IValve, sleeve and plug are free from burrs, dents and scratches.
IControl valve springs are free from damage, deformation and fatigue.
IHydraulic line is free from obstacles.
SAT367H
OK or NG
OK©GO TO 4.
NG©Repair control valve.
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0744 IMPROPER LOCK-UP OPERATION
Diagnostic Procedure
AT-157

4 CHECK SHIFT UP (D3TO D4)
Does A/T shift from D3to D4at the specified speed?
YesorNo
Ye s©GO TO 5.
No©Check control valve again. Repair or replace control valve assembly.
5 CHECK DTC
Perform Diagnostic Trouble Code (DTC) confirmation procedure, AT-154.
OK or NG
OK©INSPECTION END
NG©IGO TO 10.
IAnd check for proper lock-up.
6 CHECK LINE PRESSURE SOLENOID VALVE
1. Remove control valve assembly. Refer to AT-273.
2. Check line pressure solenoid valve operation. Refer to AT-161.
SAT158J
OK or NG
OK©GO TO 7.
NG©Replace solenoid valve assembly.
DTC P0744 IMPROPER LOCK-UP OPERATION
Diagnostic Procedure (Cont'd)
AT-158