2001 INFINITI QX4 low oil pressure

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

SAT341H
DescriptionNBAT0057The line pressure solenoid valve regulates the oil pump discharge
pressure to suit the driving condition in response to a signal sent
from the TCM.
The line pressure duty cycle value is not consistent when the
closed throttle position switch is ªONº. To confirm the line
pressure duty cycle at low pressure, the accelerator (throttle)
should be open until the closed throttle position switch is
ªOFFº.
CONSULT-II REFERENCE VALUE IN DATA MONITOR
MODE
NBAT0057S02Remarks: 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%
NOTE:
The line pressure duty cycle value is not consistent when the closed throttle position switch is ªONº. To confirm the line pressure duty
cycle at low pressure, the accelerator (throttle) should be open until the closed throttle position switch is ªOFFº.
TCM TERMINALS AND REFERENCE VALUENBAT0057S03Remarks: 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
ON BOARD DIAGNOSIS LOGICNBAT0057S04
Diagnostic trouble code Malfunction is detected when ... Check item (Possible cause)
: L/PRESS SOL/CIRCTCM detects an improper voltage drop
when it tries to operate the solenoid
valve.IHarness or connectors
(The solenoid circuit is open or shorted.)
ILine pressure solenoid valve
: P0745
DTC P0745 LINE PRESSURE SOLENOID VALVE
Description
AT-162

6. Vehicle Does Not Creep Backward In ªRº
Position
=NBAT0078SYMPTOM:
Vehicle does not creep backward when selecting ªRº position.
1 CHECK A/T FLUID LEVEL
Check A/T fluid level again.
SAT638A
OK or NG
OK©GO TO 2.
NG©Refill ATF.
2 CHECK STALL TEST
Check stall revolution with selector lever in ª1º and ªRº positions.
Refer to AT-356.
SAT493G
OK or NG
OK©GO TO 3.
OK in ª1º position, NG in
ªRº position©1. Remove control valve assembly. Refer to ªON-VEHICLE SERVICEº, AT-273.
2. Check the following items:
IValves to control line pressure (Pressure regulator valve, pressure modifier valve, pilot
valve and pilot filter)
ILine pressure solenoid valve
3. Disassemble A/T.
4. Check the following items:
IOil pump assembly
ITorque converter
IReverse clutch assembly
IHigh clutch assembly
NG in both ª1º and ªRº
positions©GO TO 6.
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSES FOR SYMPTOMS
6. Vehicle Does Not Creep Backward In ªRº Position
AT-227

3 CHECK LINE PRESSURE
Check line pressure at idle with selector lever in ªRº position. Refer to ªLINE PRESSURE TESTº, AT-62.
SAT494G
OK or NG
OK©GO TO 4.
NG©1. Remove control valve assembly. Refer to ªON-VEHICLE SERVICEº, AT-273.
2. Check the following items:
IValves to control line pressure (Pressure regulator valve, pressure modifier valve, pilot
valve and pilot filter)
ILine pressure solenoid valve
3. Disassemble A/T.
4. Check the following items:
IOil pump assembly
4 CHECK A/T FLUID CONDITION
1. Remove oil pan.
2. Check A/T fluid condition.
SAT171B
OK or NG
OK©GO TO 5.
NG©GO TO 6.
5 CHECK SYMPTOM
Check again.
OK or NG
OK©INSPECTION END
NG©1. Perform TCM input/output signal inspection.
2. If NG, recheck TCM pin terminals for damage or loose connection with harness con-
nector.
TROUBLE DIAGNOSES FOR SYMPTOMS
6. Vehicle Does Not Creep Backward In ªRº Position (Cont'd)
AT-228

6 DETECT MALFUNCTIONING ITEM
1. Remove control valve assembly. Refer to ªON-VEHICLE SERVICEº, AT-273.
2. Check the following items:
IValves to control line pressure (Pressure regulator valve, pressure modifier valve, pilot valve and pilot filter)
ILine pressure solenoid valve
3. Disassemble A/T.
4. Check the following items:
IOil pump assembly
ITorque converter
IReverse clutch assembly
IHigh clutch assembly
ILow & reverse brake assembly
ILow one-way clutch
©Repair or replace damaged parts.GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSES FOR SYMPTOMS
6. Vehicle Does Not Creep Backward In ªRº Position (Cont'd)
AT-229

3 CHECK LINE PRESSURE
Check line pressure at idle with selector lever in ªRº position.
Refer to ªLINE PRESSURE TESTº, AT-62.
SAT494G
OK or NG
OK©GO TO 4.
NG©1. Remove control valve assembly.
Refer to AT-273.
2. Check the following items:
IValves to control line pressure (Pressure regulator valve, pressure modifier valve, pilot
valve and pilot filter)
ILine pressure solenoid valve
3. Disassemble A/T.
4. Check the following items:
IOil pump assembly
4 CHECK A/T FLUID CONDITION
1. Remove oil pan.
2. Check A/T fluid condition.
SAT171B
OK or NG
OK©GO TO 5.
NG©GO TO 6.
5 CHECK SYMPTOM
Check again.
OK or NG
OK©INSPECTION END
NG©1. Perform TCM input/output signal inspection.
2. If NG, recheck TCM pin terminals for damage or loose connection with harness con-
nector.
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
TROUBLE DIAGNOSES FOR SYMPTOMS
7. Vehicle Does Not Creep Forward In ªDº, ª2º Or ª1º Position (Cont'd)
AT-231

6 DETECT MALFUNCTIONING ITEM
1. Remove control valve assembly. Refer to ªON-VEHICLE SERVICEº, AT-273.
2. Check the following items:
IValves to control line pressure (Pressure regulator valve, pressure modifier valve, pilot valve and pilot filter)
ILine pressure solenoid valve
3. Disassemble A/T.
4. Check the following items:
IOil pump assembly
IForward clutch assembly
IForward one-way clutch
ILow one-way clutch
ILow & reverse brake assembly
ITorque converter
©Repair or replace damaged parts.
TROUBLE DIAGNOSES FOR SYMPTOMS
7. Vehicle Does Not Creep Forward In ªDº, ª2º Or ª1º Position (Cont'd)
AT-232

4 CHECK LINE PRESSURE
Check line pressure at stall point with selector lever in ªDº position.
Refer to ªLINE PRESSURE TESTº, AT-62.
SAT494G
OK or NG
OK©GO TO 5.
NG©GO TO 8.
5 CHECK A/T FLUID CONDITION
1. Remove oil pan.
2. Check A/T fluid condition.
SAT171B
OK or NG
OK©GO TO 6.
NG©GO TO 8.
6 DETECT MALFUNCTIONING ITEM
1. Remove control valve assembly.
Refer to AT-273.
2. Check the following items:
IShift valve A
IShift valve B
IShift solenoid valve A
IShift solenoid valve B
IPilot valve
IPilot filter
OK or NG
OK©GO TO 7.
NG©Repair or replace damaged parts.
TROUBLE DIAGNOSES FOR SYMPTOMS
8. Vehicle Cannot Be Started From D1(Cont'd)
AT-234