ignition INFINITI QX56 2004 Factory Workshop Manual

DTC P0725 ENGINE SPEED SIGNAL
AT-115
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
DTC P0725 ENGINE SPEED SIGNALPFP:24825
DescriptionUCS002E1
The engine speed signal is sent from the ECM to the TCM.
CONSULT-II Reference ValueUCS002E2
On Board Diagnosis LogicUCS002E3

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

Diagnostic trouble code “ENGINE SPEED SIG” with CONSULT-II is detected when TCM does not receive
the ignition signal from ECM during engine cranking or running.
Possible CauseUCS002E4
Harness or connectors
(The ECM to the TCM circuit is open or shorted.)
DTC Confirmation ProcedureUCS002E5
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 5 , "
Diagnostic Procedure" .
Diagnostic ProcedureUCS002E6
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis.Refer to AT- 9 3 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 1 0 3 , "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-116
DTC P0725 ENGINE SPEED SIGNAL
Revision: August 20072004 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.
With GST
Follow the procedure “With CONSULT-II”.
OK or NG
OK >> GO TO 3.
NG >> Check the ignition signal circuit.

Refer to EC-583, "IGNITION SIGNAL" .
3. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT- 9 0 , "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 4.
NG >> GO TO 6.
4. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-115, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 5.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT-241, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
6. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> GO TO 7.
NG >> Repair or replace damaged parts.
Item name Condition Display value (rpm)
ENGINE SPEED Engine running Closely matches the tachometer reading.
PCIA0041E

AT-118
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
Revision: August 20072004 QX56
DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVEPFP:31940
DescriptionUCS002E7

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 ValueUCS002E8
On Board Diagnosis LogicUCS002E9

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “TCC SOLENOID/CIRC” with CONSULT-II or P0740 without 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 CauseUCS002EA

Torque converter clutch solenoid valve

Harness or connectors
(The solenoid circuit is open or shorted.)
DTC Confirmation ProcedureUCS002EB
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-119, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.) (A)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4
When performing lock-up 0.4 - 0.6
BCIA0030E

DTC P0740 TORQUE CONVERTER CLUTCH SOLENOID VALVE
AT-119
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
Diagnostic ProcedureUCS002EC
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
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 6.
NG >> GO TO 2.
2. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT- 11 8 , "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT - 2 4 1 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
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-121
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)PFP:31940
DescriptionUCS002ED
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 ValueUCS002EE
On Board Diagnosis LogicUCS002EF

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “A/T TCC S/V FNCTN” with CONSULT-II or P0744 without 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 CauseUCS002EG

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

Torque converter clutch solenoid valve

Hydraulic control circuit
DTC Confirmation ProcedureUCS002EH
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- 6 7 , "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- 1 2 2 , "
Diagnostic Procedure" .
Refer to shift schedule, AT-67, "
Vehicle Speed When Performing and Releasing Complete Lock-up" .
Item name Condition Display value (Approx.) (A)
TCC SOLENOIDWhen performing slip lock-up 0.2 - 0.4
When performing lock-up 0.4 - 0.6
BCIA0030E

AT-122
DTC P0744 A/T TCC S/V FUNCTION (LOCK-UP)
Revision: August 20072004 QX56
WITH GST
Follow the procedure “With CONSULT-II”.
Diagnostic ProcedureUCS002EI
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
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 6.
NG >> GO TO 2.
2. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT- 9 0 , "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT-121, "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT-241, "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
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

AT-124
DTC P0745 LINE PRESSURE SOLENOID VALVE
Revision: August 20072004 QX56
DTC P0745 LINE PRESSURE SOLENOID VALVEPFP:31940
DescriptionUCS002EJ
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 ValueUCS002EK
On Board Diagnosis LogicUCS002EL

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “L/PRESS SOL/CIRC” with CONSULT-II or P0745 without 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 CauseUCS002EM

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

Line pressure solenoid valve
DTC Confirmation ProcedureUCS002EN
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-125, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.) (A)
LINE PRES SOL During driving 0.2 - 0.6
BCIA0030E

DTC P0745 LINE PRESSURE SOLENOID VALVE
AT-125
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
Diagnostic ProcedureUCS002EO
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “A/T”
with CONSULT-II.
3. Start the engine.
4. Read out the value of “LINE PRES SOL” while driving.
OK or NG
OK >> GO TO 6.
NG >> GO TO 2.
2. CHECK TCM
Perform TCM input/output signals inspection. Refer to AT-90, "
TCM Input/Output Signal Reference Values" .
OK or NG
OK >> GO TO 3.
NG >> GO TO 5.
3. CHECK DTC
Perform “DTC Confirmation Procedure”.

Refer to AT- 1 2 4 , "DTC Confirmation Procedure" .
OK or NG
OK >>INSPECTION END
NG >> GO TO 4.
4. DETECT MALFUNCTIONING ITEM
Check the following items:

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT - 2 4 1 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
5. DETECT MALFUNCTIONING ITEM
Check the following items:

Power supply and ground circuit for TCM.

The A/T assembly harness connector terminals for damage or loose connection with harness connector.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace damaged parts.
Item name Condition Display value (Approx.)
LINE PRES SOL During driving 0.2 - 0.6 A
SCIA4793E

DTC P1702 TRANSMISSION CONTROL MODULE (RAM)
AT-127
D
E
F
G
H
I
J
K
L
MA
B
AT
Revision: August 20072004 QX56
DTC P1702 TRANSMISSION CONTROL MODULE (RAM)PFP:31036
DescriptionUCS002EP
The TCM consists of a microcomputer and connectors for signal input and output and for power supply. The
TCM controls the A/T.
On Board Diagnosis LogicUCS002EQ

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

Diagnostic trouble code “TCM·RAM” with CONSULT-II is detected when TCM memory RAM is malfunc-
tioning.
Possible CauseUCS002ER
TCM.
DTC Confirmation ProcedureUCS002ES
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 “A/T” with CONSULT-II.
3. Start engine.
4. Run engine for at least 2 consecutive seconds at idle speed.
5. If DTC is detected, go to AT - 1 2 7 , "
Diagnostic Procedure" .
Diagnostic ProcedureUCS002ET
1. CHECK DTC
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
3. Touch “ERASE”.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Perform “DTC Confirmation Procedure”, AT-127, "
DTC Confir-
mation Procedure" .
Is the
“TCM·RAM” displayed again?
YES >> Replace the control valve with TCM. Refer to AT-241,
"Control Valve With TCM and A/T Fluid Temperature
Sensor 2" .
NO >>INSPECTION END
BCIA0030E
BCIA0031E

AT-128
DTC P1703 TRANSMISSION CONTROL MODULE (ROM)
Revision: August 20072004 QX56
DTC P1703 TRANSMISSION CONTROL MODULE (ROM)PFP:31036
DescriptionUCS002EU
The TCM consists of a microcomputer and connectors for signal input and output and for power supply. The
TCM controls the A/T.
On Board Diagnosis LogicUCS002EV

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

Diagnostic trouble code “TCM·ROM” with CONSULT-II is detected when TCM memory ROM is malfunc-
tioning.
Possible CauseUCS002EW
TCM.
DTC Confirmation Procedure UCS002EX
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 to “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for A/T with CONSULT-II.
3. Start engine.
4. Run engine for at least 2 consecutive seconds at idle speed.
5. If DTC is detected, go to AT-128, "
Diagnostic Procedure" .
Diagnostic ProcedureUCS002EY
1. CHECK DTC
With CONSULT-II
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.
3. Touch “ERASE”.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Perform “DTC Confirmation Procedure”, AT-128, "
DTC Confir-
mation Procedure" .
Is the
“TCM·ROM” displayed again?
YES >> Replace the control valve with TCM. Refer to AT-241,
"Control Valve With TCM and A/T Fluid Temperature
Sensor 2" .
NO >>INSPECTION END
BCIA0030E
BCIA0031E