INFINITI QX4 2005 Factory Service Manual

AT-110
DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)
Revision: October 20052005 QX56
Wiring Diagram — AT — VSSA/TECS00CFF
BCWA0322E

DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)
AT-111
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Revision: October 20052005 QX56
Diagnostic ProcedureECS00CFG
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”.
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T” with CONSULT-II.
3. Start the engine.
4. Read out the value of “VHCL/S SE·A/T” while driving.
Check the value changes according to driving speed.
OK or NG
OK >> GO TO 6.
NG >> GO TO 2.
2. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT- 1 6 8 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT"
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector pin terminals for damage or loose connection with harness connec-
tor.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
Item name Condition Display value (km/h)
VHCL/S SE·A/T During driving Approximately matches the
speedometer reading.
SCIA2148E

AT-112
DTC P0720 VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)
Revision: October 20052005 QX56
4. CHECK SUB-HARNESS
1. Remove control valve with TCM. Refer to AT-231, "
Control Valve With TCM and A/T Fluid Temperature
Sensor 2" .
2. Disconnect park/neutral position switch connector and TCM connector.
3. Check continuity between park/neutral position switch connector
terminals and TCM connector terminals.
4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.
OK or NG
OK >> GO TO 5.
NG >> Replace open circuit or short to ground and short to power in harness or connectors.
5. REPLACE THE REVOLUTION SENSOR AND CHECK DTC
1. Replace the revolution sensor. Refer to AT-262, "
Disassembly" .
2. Perform “DTC Confirmation Procedure”. Refer to AT-108, "
DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> Replace the control valve with TCM. Refer to AT-231, "
Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
6. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-108, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
Item Connector Terminal
(Wire color)Continuity
Park/neutral position switch
connectorF505 8 (Y)
Ye s
TCM connector F503 20 (Y)
Park/neutral position switch
connectorF505 9 (R)
Ye s
TCM connector F503 17 (R)
Park/neutral position switch
connectorF505 10 (B)
Ye s
TCM connector F503 16 (B)
SCIA5458E

DTC P0725 ENGINE SPEED SIGNAL
AT-113
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Revision: October 20052005 QX56
DTC P0725 ENGINE SPEED SIGNALPFP:24825
DescriptionECS00CFH
The engine speed signal is sent from the ECM to the TCM.
CONSULT-II Reference ValueECS00CFI
On Board Diagnosis LogicECS0 0CF J

This is not an OBD-II self-diagnostic item.

Diagnostic trouble code “P0725 ENGINE SPEED SIG” with CONSULT-II is detected when TCM does not
receive the ignition signal from ECM during engine cranking or running.
Possible CauseECS00CFK
Harness or connectors
(The ECM to the TCM circuit is open or shorted.)
DTC Confirmation ProcedureECS00CFL
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Turn ignition switch “ON” and select “DATA MONITOR” mode for
“A/T” 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
ACCELE POSI: More than 1/8
Selector lever: “D” position
3. If DTC is detected, go to AT - 11 3 , "
Diagnostic Procedure" .
Diagnostic ProcedureECS0 0CF M
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer to AT - 8 5 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 9 5 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
Item name Condition Display value (rpm)
ENGINE SPEED Engine running Closely matches the tachometer reading.
BCIA0030E

AT-114
DTC P0725 ENGINE SPEED SIGNAL
Revision: October 20052005 QX56
2. CHECK DTC WITH TCM
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T” with CONSULT-II.
3. While monitoring engine speed, check for engine speed change
corresponding to wide-open throttle position signal.
OK or NG
OK >> GO TO 3.
NG >> Check the ignition signal circuit.

Refer to EC-619, "IGNITION SIGNAL" .
3. CHECK DTC
Perform "DTC Confirmation Procedure".

Refer to AT-113, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT- 1 6 8 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
OK or NG
OK >> GO TO 5.
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector pin terminals for damage or loose connection with harness connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT-231, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
Item name Condition Display value (rpm)
ENGINE SPEED Engine running Closely matches the tachometer reading.
PCIA0041E

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
AT-115
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Revision: October 20052005 QX56
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVEPFP:31940
DescriptionECS00CFN

The torque converter clutch solenoid valve is activated, with the gear in D4 , D5 by the TCM in response
to signals sent from the vehicle speed sensor and accelerator pedal position sensor (throttle position sen-
sor). Torque converter clutch piston operation will then be controlled.

Lock-up operation, however, is prohibited when A/T fluid temperature is too low.

When the accelerator pedal is depressed (less than 1/8) 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 ValueECS00CFO
On Board Diagnosis LogicECS00CFP

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P0740 TCC SOLENOID/CIRC” with CONSULT-II is detected under the following
conditions.
–When TCM detects an improper voltage drop when it tries to operate the solenoid valve.
–When TCM detects as irregular by comparing target value with monitor value.
Possible CauseECS00CFQ

Torque converter clutch solenoid valve

Harness or connectors
(The solenoid circuit is open or shorted.)
DTC Confirmation ProcedureECS00CFR
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “ENGINE” with CONSULT-II.
3. Start engine and maintain the following conditions for at least 5
consecutive seconds.
VHCL SPEED SE: 80 km/h (50 MPH) or more
ACCELE POS: 0.5/8 - 1.0/8
SELECTOR LEVER: “D” position
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.
4. If DTC is detected go to AT- 11 6 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4 A
When performing lock-up 0.4 - 0.6 A
BCIA0030E

AT-116
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
Revision: October 20052005 QX56
Diagnostic ProcedureECS00CFS
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”.
2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “A/T”
with CONSULT-II.
3. Start engine.
4. Read out the value of “TCC SOLENOID” while driving.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT- 1 6 8 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector pin terminals for damage or loose connection with harness connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT-231, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
4. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-115, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
Item name Condition Display value (Approx.)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4 A
When performing lock-up 0.4 - 0.6 A
SCIA4793E

DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)
AT-117
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Revision: October 20052005 QX56
DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)PFP:31940
DescriptionECS00CFT
This malfunction is detected when the A/T does not shift into 5th gear position or the torque converter clutch
does not lock-up as instructed by the TCM. This is not only caused by electrical malfunction (circuits open or
shorted) but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation,
etc.
CONSULT-II Reference ValueECS00CFU
On Board Diagnosis LogicECS00CFV

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P0744 A/T TCC S/V FNCTN” with CONSULT-II is detected under the following
conditions.
–When A/T cannot perform lock-up even if electrical circuit is good.
–When TCM detects as irregular by comparing difference value with slip rotation.
Possible CauseECS00CFW

Harness or connectors
(The solenoid circuit is open or shorted.)

Torque converter clutch solenoid valve

Hydraulic control circuit
DTC Confirmation ProcedureECS00CFX
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Start engine and Select “TCC S/V FNCTN CHECK” of “DTC
WORK SUPPORT” mode for “A/T” with CONSULT-II and touch
“START”.
2. Accelerate vehicle to more than 80 km/h (50 MPH) and maintain
the following condition continuously until “TESTING” has turned
to “COMPLETE”. (It will take approximately 30 seconds after
“TESTING” shows.)
ACCELE POSI: More than 1.0/8 (at all times during step 4)
TCC SOLENOID: 0.4 - 0.6 A
Selector lever: “D” position
[Reference speed: Constant speed of more than 80 km/h (50
MPH)]
–Make sure “GEAR” shows “5”.
–For shift schedule, refer to AT- 3 2 2 , "Vehicle Speed When Performing and Releasing Complete
Lock-up" .
–If “TESTING” does not appear on CONSULT-II for a long time, select “SELF-DIAG RESULTS”. In
case a 1st trip DTC other than P0744 is shown, refer to applicable “TROUBLE DIAGNOSIS FOR
DTC”.
3. Make sure that “OK” is displayed. (If “NG” is displayed, refer to “DIAGNOSTIC PROCEDURE”.)
Refer to AT- 11 8 , "
Diagnostic Procedure" .
Refer to shift schedule, AT-322, "
Vehicle Speed When Performing and Releasing Complete Lock-up" .
Item name Condition Display value (Approx.)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4 A
When performing lock-up 0.4 - 0.6 A
BCIA0030E

AT-118
DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)
Revision: October 20052005 QX56
WITH GST
Follow the procedure “With CONSULT-II”.
Diagnostic ProcedureECS00CFY
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”.
2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “A/T”
with CONSULT-II.
3. Start the engine.
4. Read out the value of “TCC SOLENOID” while driving.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit. Refer to AT- 1 6 8 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector pin terminals for damage or loose connection with harness connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT-231, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
4. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-117, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 2.
Item name Condition Display value (Approx.)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4 A
When performing lock-up 0.4 - 0.6 A
SCIA4793E

DTC P0745 LINE PRESSURE SOLENOID VALVE
AT-119
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Revision: October 20052005 QX56
DTC P0745 LINE PRESSURE SOLENOID VALVEPFP:31940
DescriptionECS00CFZ
The 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 signal is “ON”.
To confirm the line pressure duty cycle at low pressure, the accelerator (throttle) should be open until
the closed throttle position signal is “OFF”.
CONSULT-II Reference ValueECS00CG0
On Board Diagnosis LogicECS00CG1

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P0745 L/PRESS SOL/CIRC” with CONSULT-II is detected under the following
conditions.
–When TCM detects an improper voltage drop when it tries to operate the solenoid valve.
–When TCM detects as irregular by comparing target value with monitor value.
Possible CauseECS00CG2

Harness or connectors
(The solenoid circuit is open or shorted.)

Line pressure solenoid valve
DTC Confirmation ProcedureECS00CG3
NOTE:
If “DTC Confirmation Procedure” has been previously performed, always turn ignition switch “OFF”
and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Turn ignition switch “ON” and select “DATA MONITOR” mode for
“ENGINE” with CONSULT-II.
2. Engine start and wait at least 5 second.
3. If DTC is detected, go to AT-120, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
LINE PRES SOL During driving 0.2 - 0.6 A
BCIA0030E