2009 INFINITI QX56 engine

P0725 ENGINE SPEEDTM-53
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
NG >> Check the ignition signal circuit.  Refer to EC-404, "Diagnosis Procedure"
.
3.CHECK DTC
Perform "DTC Confirmation Procedure".
 Refer to TM-52, "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 TM-92, "Diagnosis Procedure"
.
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 connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to TM-203, "Control Valve with TCM and A/T Fluid
Temperature Sensor 2".
NG >> Repair or replace damaged parts.
Revision: December 20092009 QX56

TM-54
< COMPONENT DIAGNOSIS >
P0731 1GR INCORRECT RATIO
P0731 1GR INCORRECT RATIO
DescriptionINFOID:0000000003771865
This malfunction is detected when the A/T does not shift into 1GR position as instructed by 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.
On Board Diagn osis LogicINFOID:0000000003771866
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P0731” is detected when TCM detec ts any inconsistency in the actual gear ratio.
Possible CauseINFOID:0000000003771867
 Harness or connectors
(Solenoid circuits are open or shorted.)
 Input clutch solenoid valve
 Front brake solenoid valve
 Direct clutch solenoid valve
 High and low reverse clutch solenoid valve
 Each clutch
 Hydraulic control circuit
DTC Confirmation ProcedureINFOID:0000000003771868
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, alw ays turn ignition switch OFF and
wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Start the engine and select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
2. Make sure that “ATF TEMP 1” is within the following range. ATF TEMP 1: 20 °C – 140 °C
If out of range, drive vehicle to warm ATF or stop engine to cool ATF.
3. Select “1ST GR FNCTN P0731” of “DTC WORK SUPPORT” mode for “TRANSMISSION” with CON-
SULT-III.
4. Drive vehicle and maintain the following conditions.
VEHICLE SPEED: 10 km/h (6 MPH) or more
ACCELE POSI: 0.6/8 or more
ENGINE SPEED: INPUT SPEED − 50 rpm or more
INPUT SPEED: 300 rpm or more
GEAR: “1” position
MANU MODE SW: ON
5. Keep the current driving status for at least 5 consecutive seconds if CONSULT-III screen changes from
“OUT OF CONDITION” to “TESTING”.
CAUTION:
If “TESTING” does not ap pear on CONSULT-III for a long ti me, select “SELF-DIAG RESULTS”. In
case a 1st trip DTC other than P0731 is shown, refer to “ TM-117, "DTC No. Index"
”.
If “COMPLETED RESULT NG” is detected, go to TM-55, "Diagnosis Procedure"
.
If “STOP VEHICLE” is detect ed, go to the following step.
6. Stop vehicle.
7. Drive vehicle in “D” position allowing it to shif t from 1GR to 5GR gear and check shift timing and shift
shock.
- Touch “OK” to complete the inspection when normally shifted from the 1GR to 5GR.
- Touch “NG” when an unusual shift shock, etc. occurs in spite of shifting from the 1GR to 5GR. Go to TM-
190, "Description".
- Perform TM-32, "CONSULT-III Function (TRANSMISSION)"
when not shifted from the 1GR to 5GR. (Nei-
ther “OK” nor “NG” are indicated.)
Revision: December 20092009 QX56

TM-56
< COMPONENT DIAGNOSIS >
P0732 2GR INCORRECT RATIO
P0732 2GR INCORRECT RATIO
DescriptionINFOID:0000000003771870
This malfunction is detected when the A/T does not shift into 2GR position as instructed by 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.
On Board Diagn osis LogicINFOID:0000000003771871
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P0732” detected when TCM detects any inconsistency in the actual gear ratio.
Possible CauseINFOID:0000000003771872
 Harness or connectors
(Solenoid circuits are open or shorted.)
 Input clutch solenoid valve
 Front brake solenoid valve
 Direct clutch solenoid valve
 High and low reverse clutch solenoid valve
 Each clutch
 Hydraulic control circuit
DTC Confirmation ProcedureINFOID:0000000003771873
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, alw ays turn ignition switch OFF and
wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Start the engine and select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
2. Make sure that “ATF TEMP 1” is within the following range. ATF TEMP 1: 20 °C – 140 °C
If out of range, drive vehicle to warm ATF or stop engine to cool ATF.
3. Select “2ND GR FNCTN P0732” of “DTC WORK SUPPORT” mode for “TRANSMISSION” with CON-
SULT-III.
4. Drive vehicle and maintain the following conditions.
VEHICLE SPEED: 10 km/h (6 MPH) or more
ACCELE POSI: 0.6/8 or more
ENGINE SPEED: INPUT SPEED − 50 rpm or more
INPUT SPEED: 300 rpm or more
GEAR: “2” position
MANU MODE SW: ON
5. Keep the current driving status for at least 5 consecutive seconds if CONSULT-III screen changes from
“OUT OF CONDITION” to “TESTING”.
CAUTION:
If “TESTING” does not ap pear on CONSULT-III for a long ti me, select “SELF-DIAG RESULTS”. In
case a 1st trip DTC other than P0732 is shown, refer to “ TM-117, "DTC No. Index"
”.
If “COMPLETED RESULT NG” is detected, go to TM-57, "Diagnosis Procedure"
.
If “STOP VEHICLE” is detect ed, go to the following step.
6. Stop vehicle.
7. Drive vehicle in “D” position allowing it to shift from 1GR to 5GR and check shift timing and shift shock.
- Touch “OK” to complete the inspection when normally shifted from the 1GR to 5GR.
- Touch “NG” when an unusual shift shock, etc. occurs in spite of shifting from the 1GR to 5GR. Go to TM-
190, "Description".
- Perform TM-32, "CONSULT-III Function (TRANSMISSION)"
when not shifted from the 1GR to 5GR. (Nei-
ther “OK” nor “NG” are indicated.)
Revision: December 20092009 QX56

TM-58
< COMPONENT DIAGNOSIS >
P0733 3GR INCORRECT RATIO
P0733 3GR INCORRECT RATIO
DescriptionINFOID:0000000003771875
This malfunction is detected when the A/T does not shift into 3GR position as instructed by 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.
On Board Diagn osis LogicINFOID:0000000003771876
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P0733” is detected when TCM detec ts any inconsistency in the actual gear ratio.
Possible CauseINFOID:0000000003771877
 Harness or connectors
(Solenoid circuits are open or shorted.)
 Input clutch solenoid valve
 Front brake solenoid valve
 Direct clutch solenoid valve
 High and low reverse clutch solenoid valve
 Each clutch
 Hydraulic control circuit
DTC Confirmation ProcedureINFOID:0000000003771878
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, alw ays turn ignition switch OFF and
wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Start the engine and select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
2. Make sure that “ATF TEMP 1” is within the following range. ATF TEMP 1: 20 °C – 140 °C
If out of range, drive vehicle to warm ATF or stop engine to cool ATF.
3. Select “3RD GR FNCTN P0733” of “DTC WORK SUPPORT” mode for “TRANSMISSION” with CON-
SULT-III.
4. Drive vehicle and maintain the following conditions.
VEHICLE SPEED: 10 km/h (6 MPH) or more
ACCELE POSI: 0.6/8 or more
ENGINE SPEED: INPUT SPEED − 50 rpm or more
INPUT SPEED: 300 rpm or more
GEAR: “3” position
MANU MODE SW: ON
5. Keep the current driving status for at least 5 consecutive seconds if CONSULT-III screen changes from
“OUT OF CONDITION” to “TESTING”.
CAUTION:
If “TESTING” does not ap pear on CONSULT-III for a long ti me, select “SELF-DIAG RESULTS”. In
case a 1st trip DTC other than P0732 is shown, refer to “ TM-117, "DTC No. Index"
”.
If “COMPLETED RESULT NG” is detected, go to TM-59, "Diagnosis Procedure"
.
If “STOP VEHICLE” is detect ed, go to the following step.
6. Stop vehicle.
7. Drive vehicle in “D” position allowing it to shift from 1GR to 5GR and check shift timing and shift shock.
- Touch “OK” to complete the inspection when normally shifted from the 1GR to 5GR.
- Touch “NG” when an unusual shift shock, etc. occurs in spite of shifting from the 1GR to 5GR. Go to TM-
190, "Description".
- Perform TM-32, "CONSULT-III Function (TRANSMISSION)"
when not shifted from the 1GR to 5GR. (Nei-
ther “OK” nor “NG” are indicated.)
Revision: December 20092009 QX56

TM-60
< COMPONENT DIAGNOSIS >
P0734 4GR INCORRECT RATIO
P0734 4GR INCORRECT RATIO
DescriptionINFOID:0000000003771880
This malfunction is detected when the A/T does not shift into 4GR position as instructed by 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.
On Board Diagn osis LogicINFOID:0000000003771881
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P0734” is detected when TCM detec ts any inconsistency in the actual gear ratio.
Possible CauseINFOID:0000000003771882
 Harness or connectors
(Solenoid circuits are open or shorted.)
 Input clutch solenoid valve
 Front brake solenoid valve
 Direct clutch solenoid valve
 High and low reverse clutch solenoid valve
 Each clutch
 Hydraulic control circuit
DTC Confirmation ProcedureINFOID:0000000003771883
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, alw ays turn ignition switch OFF and
wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Start the engine and select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
2. Make sure that “ATF TEMP 1” is within the following range. ATF TEMP 1: 20 °C – 140 °C
If out of range, drive vehicle to warm ATF or stop engine to cool ATF.
3. Select “4TH GR FNCTN P0734” of “DTC WORK SUPPORT” mode for “TRANSMISSION” with CON-
SULT-III.
4. Drive vehicle and maintain the following conditions.
VEHICLE SPEED: 10 km/h (6 MPH) or more
ACCELE POSI: 0.6/8 or more
ENGINE SPEED: INPUT SPEED − 50 rpm or more
INPUT SPEED: 300 rpm or more
GEAR: “4” position
MANU MODE SW: ON
5. Keep the current driving status for at least 5 consecutive seconds if CONSULT-III screen changes from
“OUT OF CONDITION” to “TESTING”.
CAUTION:
If “TESTING” does not ap pear on CONSULT-III for a long ti me, select “SELF-DIAG RESULTS”. In
case a 1st trip DTC other than P0734 is shown, refer to “ TM-117, "DTC No. Index"
”.
If “COMPLETED RESULT NG” is detected, go to TM-61, "Diagnosis Procedure"
.
If “STOP VEHICLE” is detect ed, go to the following step.
6. Stop vehicle.
7. Drive vehicle in “D” position allowing it to shift from 1GR to 5GR and check shift timing and shift shock.
- Touch “OK” to complete the inspection when normally shifted from the 1GR to 5GR.
- Touch “NG” when an unusual shift shock, etc. occurs in spite of shifting from the 1GR to 5GR. Go to TM-
190, "Description".
- Perform TM-32, "CONSULT-III Function (TRANSMISSION)"
when not shifted from the 1GR to 5GR. (Nei-
ther “OK” nor “NG” are indicated.)
Revision: December 20092009 QX56

TM-62
< COMPONENT DIAGNOSIS >
P0735 5GR INCORRECT RATIO
P0735 5GR INCORRECT RATIO
DescriptionINFOID:0000000003771885
This malfunction is detected when the A/T does not shift into 5GR position as instructed by 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.
On Board Diagn osis LogicINFOID:0000000003771886
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P0735” is detected when TCM detec ts any inconsistency in the actual gear ratio.
Possible CauseINFOID:0000000003771887
 Harness or connectors
(Solenoid circuits are open or shorted.)
 Input clutch solenoid valve
 Front brake solenoid valve
 Direct clutch solenoid valve
 High and low reverse clutch solenoid valve
 Each clutch
 Hydraulic control circuit
DTC Confirmation ProcedureINFOID:0000000003771888
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If “DTC Confirmation Procedure” has been previously performed, alw ays turn ignition switch OFF and
wait at least 10 seconds before performing the next test.
After the repair, perform the following proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Start the engine and select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.
2. Make sure that “ATF TEMP 1” is within the following range. ATF TEMP 1: 20 °C – 140 °C
If out of range, drive vehicle to warm ATF or stop engine to cool ATF.
3. Select “5TH GR FNCTN P0735” of “DTC WORK SUPPORT” mode for “TRANSMISSION” with CON-
SULT-III.
4. Drive vehicle and maintain the following conditions.
VEHICLE SPEED: 10 km/h (6 MPH) or more
ACCELE POSI: 0.6/8 or more
ENGINE SPEED: INPUT SPEED − 50 rpm or more
INPUT SPEED: 300 rpm or more
GEAR: “5” position
MANU MODE SW: ON
5. Keep the current driving status for at least 5 consecutive seconds if CONSULT-III screen changes from
“OUT OF CONDITION” to “TESTING”.
CAUTION:
If “TESTING” does not ap pear on CONSULT-III for a long ti me, select “SELF-DIAG RESULTS”. In
case a 1st trip DTC other than P0735 is shown, refer to “ TM-117, "DTC No. Index"
”.
If “COMPLETED RESULT NG” is detected, go to TM-63, "Diagnosis Procedure"
.
If “STOP VEHICLE” is detect ed, go to the following step.
6. Stop vehicle.
7. Drive vehicle in “D” position allowing it to shif t from 1GR to 5GR gear and check shift timing and shift
shock.
- Touch “OK” to complete the inspection when normally shifted from the 1GR to 5GR.
- Touch “NG” when an unusual shift shock, etc. occurs in spite of shifting from the 1GR to 5GR. Go to TM-
190, "Description".
- Perform TM-32, "CONSULT-III Function (TRANSMISSION)"
when not shifted from the 1GR to 5GR. (Nei-
ther “OK” nor “NG” are indicated.)
Revision: December 20092009 QX56

TM-64
< COMPONENT DIAGNOSIS >
P0740 TORQUE CONVERTER
P0740 TORQUE CONVERTER
DescriptionINFOID:0000000003771890
 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 accelera tor pedal position sensor (throttle position sensor).
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-III Reference Value in Data Monitor ModeINFOID:0000000003771891
On Board Diagnosis LogicINFOID:0000000003771892
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P0740” with CONSULT-III 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 CauseINFOID:0000000003771893
 Torque converter clutch solenoid valve
 Harness or connectors (The solenoid circuit is open or shorted.)
DTC Confirmation ProcedureINFOID:0000000003771894
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 proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Turn ignition switch “ON”. (Do not start engine.)
2. Select “DATA MONITOR” mode for “ENGINE” with CONSULT-III.
3. Start engine and maintain the following conditions for at least 5 consecutive seconds.
VHCL/S SE-A/T: 80 km/h (50 MPH) or more
ACCELE POSI: 0.5/8 - 1.0/8
SLCT LVR POSI: “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 TM-64, "Diagnosis Procedure"
.
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000003771895
1.CHECK INPUT SIGNAL
With CONSULT-III
1. Turn ignition switch “ON”.
2. Select “MAIN SIGNALS” in “DATA MONITO R” mode for “TRANSMISSION” with CONSULT-III.
3. Start engine.
Item name Condition Display value (Approx.)
TCC SOLENOID When performing slip lock-up 0.2 - 0.4 A
When performing lock-up 0.4 - 0.6 A
Revision: December 20092009 QX56

TM-66
< COMPONENT DIAGNOSIS >
P0744 TORQUE CONVERTER
P0744 TORQUE CONVERTER
DescriptionINFOID:0000000003771896
This malfunction is detected when the A/T does not lock-up. This is not only caused by electrical malfunction
(circuits open or shorted) but also by mechanical malfunc tion such as control valve sticking, improper solenoid
valve operation, etc.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000003771897
On Board Diagn osis LogicINFOID:0000000003771898
 This is an OBD-II self-diagnostic item.
 Diagnostic trouble code “P0744” with CONSULT-III 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 CauseINFOID:0000000003771899
 Harness or connectors
(The solenoid circuit is open or shorted.)
 Torque converter clutch solenoid valve
 Hydraulic control circuit
DTC Confirmation ProcedureINFOID:0000000003771900
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 proc edure to confirm the malfunction is eliminated.
WITH CONSULT-III
1. Start engine and Select “TCC S/V FNCTN CHECK” of “DTC WORK SUPPORT” mode for “TRANSMIS-
SION” with CONSULT-III 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
SLCT LVR POSI: “D” position
[Reference speed: Constant speed of more than 80 km/h (50 MPH)]
- Make sure “GEAR” shows “5”.
- For shift schedule, refer to TM-291, "Vehicle Speed at Which Lock-up Occurs/Releases"
.
- If “TESTING” does not ap pear on CONSULT-III for a long ti me, 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 TM-67, "Diagnosis Procedure"
.
Refer to shift schedule, TM-291, "Vehicle Speed at Which Lock-up Occurs/Releases"
.
WITH GST
Follow the procedure “With CONSULT-III”.
Item name Condition Display value (Approx.)
TCC SOLENOID When performing slip lock-up 0.2 - 0.4 A
When performing lock-up 0.4 - 0.6 A
Revision: December 20092009 QX56