2001 INFINITI QX4 check engine

Diagnostic ProcedureNBAT0035
1 INSPECTION START
Do you have CONSULT-II?
YesorNo
Yes (With CONSULT-II)©GO TO 2.
No (Without CONSULT-
II)©GO TO 5.
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 ªVHCL/S SE´A/Tº while driving.
Check the value changes according to driving speed.
SAT614J
OK or NG
OK©GO TO 3.
NG©GO TO 4.
3 CHECK REVOLUTION SENSOR
Refer to ªComponent Inspectionº, AT-115.
OK or NG
OK©GO TO 6.
NG©Repair or replace revolution sensor.
4 DETECT MALFUNCTIONING ITEM
Check the following items:
IHarness for short or open between TCM and revolution sensor (Main harness)
IHarness for short or open between revolution sensor and ECM (Main harness)
IGround circuit for ECM
Refer to EC-142, ªWIRING DIAGRAMº.
OK or NG
OK©GO TO 6.
NG©GO TO 3.
DTC P0720 VEHICLE SPEED SENSOR´A/T (REVOLUTION SENSOR)
Diagnostic Procedure
AT-114

5 CHECK INPUT SIGNAL (WITHOUT CONSULT-II)
Without CONSULT-II
1. Start engine.
2. Check voltage between TCM terminal 29 and ground while driving.
(Measure with AC range.)
Voltage:
At 0 km/h (0 MPH):
0V
At 30 km/h (19 MPH):
1V or more
(Voltage rises gradually in response to vehicle speed.)
SAT519J
OK or NG
OK©GO TO 3.
NG©GO TO 4.
6 CHECK DTC
Perform Diagnostic Trouble Code (DTC) confirmation procedure, AT-112.
OK or NG
OK©INSPECTION END
NG©GO TO 7.
7 CHECK TCM INSPECTION
1. Perform TCM input/output signal inspection.
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK©INSPECTION END
NG©Repair or replace damaged parts.
SAT210IA
Component InspectionNBAT0036REVOLUTION SENSORNBAT0036S01IFor removal, refer to AT-273.
ICheck resistance between terminals 1, 2 and 3.
Terminal No. Resistance
1 2 500 - 650W
2 3 No continuity
1 3 No continuity
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0720 VEHICLE SPEED SENSOR´A/T (REVOLUTION SENSOR)
Diagnostic Procedure (Cont'd)
AT-115

DescriptionNBAT0037The engine speed signal is sent from the ECM to the TCM.
TCM TERMINALS AND REFERENCE VALUENBAT0037S02Remarks: Specification data are reference values.
Terminal
No.Wire color Item ConditionJudgement
standard
(Approx.)
39 W/BEngine speed sig-
nal
Refer to EC-127, ªECM INSPECTION
TABLEº.Ð
ON BOARD DIAGNOSIS LOGICNBAT0037S03
Diagnostic trouble code Malfunction is detected when ... Check item (Possible cause)
: ENGINE SPEED SIG
TCM does not receive the proper voltage
signal from ECM.IHarness or connectors
(The sensor circuit is open or shorted.)
: P0725
SAT014K
SAT020K
DIAGNOSTIC TROUBLE CODE (DTC) CONFIRMATION
PROCEDURE
NBAT0037S01CAUTION:
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) Turn ignition switch ªONº and select ªDATA MONITORº mode
for ªENGINEº with CONSULT-II.
2) Start engine and maintain the following conditions for at least
10 consecutive seconds.
VHCL SPEED SE: 10 km/h (6 MPH) or more
THRTL POS SEN: More than 1.2V
Selector lever: D position (OD ªONº)
With GST
Follow the procedure ªWith CONSULT-IIº.
DTC P0725 ENGINE SPEED SIGNAL
Description
AT-116

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

4 CHECK INPUT SIGNAL (WITHOUT CONSULT-II)
Without CONSULT-II
1. Start engine.
2. Check voltage between TCM terminal 39 and ground.
SAT520J
Refer toEC-127, ªECM INSPECTION TABLEº.
Ye s©GO TO 4.
No©GO TO 3.
5 CHECK DTC
Perform Diagnostic Trouble Code (DTC) confirmation procedure, AT-116.
OK or NG
OK©INSPECTION END
NG©GO TO 6.
6 CHECK TCM INSPECTION
1. Perform TCM input/output signal inspection.
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK©INSPECTION END
NG©Repair or replace damaged parts.
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0725 ENGINE SPEED SIGNAL
Diagnostic Procedure (Cont'd)
AT-119

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

SAT014K
SAT971J
SAT021J
DIAGNOSTIC TROUBLE CODE (DTC) CONFIRMATION
PROCEDURE
NBAT0039S01CAUTION:
IAlways drive vehicle at a safe speed.
IBe careful not to rev engine into the red zone on the
tachometer.
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.
TESTING CONDITIONS:
Always drive vehicle on a level road to improve the accuracy of
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 ª1ST GR FNCTN P0731º of ªDTC WORK SUPPORTº
mode for ªA/Tº with CONSULT-II and touch ªSTARTº.
4) Accelerate vehicle to 10 to 20 km/h (6 to 12 MPH) under the
following condition and release the accelerator pedal com-
pletely.
THROTTLE POSI: Less than 1.0/8 (at all times during step
4)
Selector lever: D position (OD ªONº)
ICheck that ªGEARº shows ª2º after releasing pedal.
5) Depress accelerator pedal to WOT (more than 7.0/8 of
ªTHROTTLE POSIº) quickly from a speed of 10 to 20 km/h (6
to 12 MPH) until ªTESTINGº changes to ªSTOP VEHICLEº or
ªCOMPLETEDº. (It will take approximately 3 seconds.)
If the check result NG appears on CONSULT-II screen, go to
ªDIAGNOSTIC PROCEDUREº, AT-124.
If ªSTOP VEHICLEº appears on CONSULT-II screen, go to the
following step.
ICheck that ªGEARº shows ª1º when depressing accelera-
tor pedal to WOT.
IIf ªTESTINGº does not appear on CONSULT-II for a long
time, select ªSELF-DIAG RESULTSº for ªENGINEº. In case
a 1st trip DTC other than P0731 is shown, refer to appli-
cable ªTROUBLE DIAGNOSIS FOR DTCº.
6) Stop vehicle.
7) Follow the instruction displayed. (Check for normal shifting
referring to the table below.)
Vehicle conditionGear on actual transmission shift pattern when
screen is changed to 1,2,3,4
No malfunction exists 1,2,3,4
GI
MA
EM
LC
EC
FE
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
DTC P0731 IMPROPER SHIFTING TO 1ST GEAR POSITION
Description (Cont'd)
AT-121

DescriptionNBAT0042IThis 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
second 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 VALUENBAT0042S02Remarks: Specification data are reference values.
Terminal
No.Wire color Item ConditionJudgement
standard
(Approx.)
12 L/RShift solenoid
valve B
When 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 LOGICNBAT0042S03This 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 (2nd) sup-
posed by TCM, the slip ratio will be more than normal. In case the
ratio exceeds the specified value, TCM judges this diagnosis mal-
function.
This malfunction will be caused when shift solenoid valve B is stuck
open.
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 open43* 3 4
*: P0732 is detected.
Diagnostic trouble code Malfunction is detected when ... Check item (Possible cause)
: A/T 2ND GR FNCTN
A/T cannot be shifted to the 2nd gear
position even if electrical circuit is good.IShift solenoid valve B
IEach clutch
IHydraulic control circuit
: P0732
DTC P0732 IMPROPER SHIFTING TO 2ND GEAR POSITION
Description
AT-126