INFINITI QX56 2008 Factory Service Manual

TM-74
< COMPONENT DIAGNOSIS >
P1721 VEHICLE SPEED SIGNAL
P1721 VEHICLE SPEED SIGNAL
DescriptionINFOID:0000000001604106
The vehicle speed signal is transmitted from combination meter to TCM by CAN communication line. The sig-
nal functions as an auxiliary device to the output speed sensor when it is malfunctioning. The TCM will then
use the vehicle speed signal.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001604107
On Board Diagn osis LogicINFOID:0000000001604108
• This is not an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1721” with CONSULT-III is det ected when TCM does not receive the proper vehi-
cle speed signal (input by CAN communication) from combination meter.
Possible CauseINFOID:0000000001604109
Harness or connectors
(The sensor circuit is open or shorted.)
DTC Confirmation ProcedureINFOID:0000000001604110
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 “TRANSMISSION” with CONSULT-III.
3. Start engine and maintain the following conditions for at least 5 consecutive seconds. ACCELE POS: 1/8 or less
VHCL SPEED SE: 30 km/h (17 MPH) or more
4. If DTC is detected, go to TM-74, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000001604111
1.CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer TM-32, "
CONSULT-III Function (TRANSMISSION)".
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to TM-38.
NO >> GO TO 2.
2.CHECK INPUT SIGNAL
With CONSULT-III
1. Start engine.
2. Select “ECU INPUT SIGNALS” in “DATA MONI TOR” mode for “TRANSMISSION” with CONSULT-III.
3. Drive vehicle and read out the value of “VHCL/S SE·MTR”.
OK or NG
Item name Condition Display value (km/h)
VHCL/S SE·MTR During driving Approximately matches the speedometer reading.
Item nameCondition Displa y value (Approx.)(km/h)
VHCL/S SE·MTR During driving Approximately matches the speed-
ometer reading.
Revision: March 2010
2008 QX56

P1721 VEHICLE SPEED SIGNALTM-75
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
OK >> GO TO 4.
NG >> GO TO 3.
3.CHECK COMBINATION METERS
Check combination meter. Refer to MWI-4, "
Work Flow".
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4.CHECK DTC
Perform “DTC Confirmation Procedure”.
• Refer to TM-74, "
DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 5.
5.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 6.
NG >> Repair or replace damaged parts.
6.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-201, "Control Valve with TCM and A/T Fluid
Temperature Sensor 2".
NG >> Repair or replace damaged parts.
Revision: March 2010 2008 QX56

TM-76
< COMPONENT DIAGNOSIS >
P1730 INTERLOCK
P1730 INTERLOCK
DescriptionINFOID:0000000001604112
• Fail-safe function to detect interlock conditions.
On Board Diagnosis LogicINFOID:0000000001604113
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1730” with CONSULT-III is detected when TCM does not receive the proper volt-
age signal from the sensor and switch.
• TCM monitors and compares gear position and conditions of each ATF pressure switch when gear is steady.
Possible CauseINFOID:0000000001604114
• Harness or connectors (The solenoid and switch circuit is open or shorted.)
• Low coast brake solenoid valve
• ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000001604115
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 “TRANSMISSION” with CONSULT-III.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 2 consecutive seconds. Selector lever: “D” position
5. If DTC is detected, go to TM-5, "
Work Flow".
WITH GST
Follow the procedure “With CONSULT-III”.
Judgement of InterlockINFOID:0000000001604116
• When Interlock is judged to be malfunctioning, the vehi cle should be fixed in 2GR, and should be set in a
condition in which it can travel.
NOTE:
When the vehicle is driven fixed in 2GR, a input speed sensor malfunction is displayed, but this is not a input
speed sensor malfunction.
• When interlock is detected at the 3GR or more, it is locked at the 2GR.
Diagnosis ProcedureINFOID:0000000001604117
1.SELF-DIAGNOSIS
With CONSULT-III
1. Drive vehicle.
2. Stop vehicle and turn ignition switch “OFF”.
3. Turn ignition switch “ON”.
4. Select “SELF-DIAG RESULTS” mode fo r “TRANSMISSION” with CONSULT-III.
OK or NG
OK >> GO TO 2.
NG >> Check low coast brake solenoid valve circuit and function. Refer to TM-88, "
Diagnosis Proce-
dure", TM-90, "Diagnosis Procedure".
2.CHECK DTC
Perform “DTC Confirmation Procedure”.
Revision: March 2010 2008 QX56

P1730 INTERLOCKTM-77
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
• Refer to TM-76, "DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 3.
3.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 4.
NG >> Repair or replace damaged parts.
4.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-201, "Control Valve with TCM and A/T Fluid
Temperature Sensor 2".
NG >> Repair or replace damaged parts.
Revision: March 2010 2008 QX56

TM-78
< COMPONENT DIAGNOSIS >
P1731 1ST ENGINE BRAKING
P1731 1ST ENGINE BRAKING
DescriptionINFOID:0000000001604118
Fail-safe function to prevent sudden decrease in speed by engine brake other than at "1" position.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001604119
On Board Diagnosis LogicINFOID:0000000001604120
• This is not an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1731” with CONSULT-III is detected under the following conditions.
- When TCM does not receive the proper voltage signal from the sensor.
- When TCM monitors ATF pressure switch 2 and solenoid monitor value, and detects as irregular when engine brake of 1st gear acts other than at 1 position.
Possible CauseINFOID:0000000001604121
• Harness or connectors(The sensor circuit is open or shorted.)
• Low coast brake solenoid valve
• ATF pressure switch 2
DTC Confirmation ProcedureINFOID:0000000001604122
NOTE:
If “DTC Confirmation Procedure” has been previously preformed, 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 “TRANSMISSION” with CONSULT-III.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 2 consecutive seconds. ENGINE SPEED: 1,200 rpm
Selector lever: “1” position
Gear position: 1st gear
5. If DTC is detected, go to TM-78, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000001604123
1.CHECK INPUT SIGNALS
With CONSULT-III
1. Start the engine.
2. Select “SELECTION FROM MENU” in “DATA MONITOR” for "TRANSMISSION" with CONSULT-III"
3. Drive vehicle in the “1” position (1st gear), and c onfirm the ON/OFF actuation of “ATF PRES SW 2” and
"ON OFF SOL".
Item name Condition Display value
ON OFF SOL Low coast brake engaged. Refer to
TM-9
.O N
Low coast brake disengaged. Refer to TM-9
.O FF
ATF PRES SW 2 Low coast brake engaged. Refer to
TM-9
ON
Low coast brake disengaged. Refer to TM-9
.O FF
Item name Condition Display value
ON OFF
SOL Low coast brake engaged. Refer to TM-9
.O
N
Low coast brake disengaged. Refer to TM-9
.OFF
Revision: March 2010 2008 QX56

P1731 1ST ENGINE BRAKINGTM-79
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
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 TM-92, "
Diagnosis Procedure".
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 connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to TM-201, "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 TM-78, "
DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
ATF PRES
SW 2 Low coast brake engaged. Refer to
TM-9.ON
Low coast brake disengaged. Refer to TM-9
.OFF
Item name
Condition Display value
Revision: March 2010 2008 QX56

TM-80
< COMPONENT DIAGNOSIS >
P1752 INPUT CLUTCH SOLENOID
P1752 INPUT CLUTCH SOLENOID
DescriptionINFOID:0000000001604124
Input clutch solenoid valve is controlled by the TCM in response to signals sent from the transmission range
switch, output speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then
be shifted to the optimum position.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001604125
On Board Diagn osis LogicINFOID:0000000001604126
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1752” 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:0000000001604127
• Harness or connectors (The solenoid circuit is open or shorted.)
• Input clutch solenoid valve
DTC Confirmation ProcedureINFOID:0000000001604128
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 “TRANSMISSION” with CONSULT-III.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 5 consecutive seconds.
ACCELE POS: 1.5/8 - 2.0/8
Selector lever: “D” position
Gear position: 3rd ⇒ 4GR (I/C ON/OFF)
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving
conditions required for this test.
5. If DTC is detected go to TM-80, "
Diagnosis Procedure".
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000001604129
1.CHECK INPUT SIGNAL
With CONSULT-III
1. Turn ignition switch “ON”.
2. Select “MAIN SIGNALS” in “DATA MONITOR” mode for “TRANMSMISSION” with CONSULT-III.
3. Start the engine.
4. Read out the value of “I/C SOLENOID” while driving.
Item name Condition Display value (Approx.)
I/C SOLENOID Input clutch disengaged. Refer to
TM-9
.0.6 - 0.8 A
Input clutch engaged. Refer to TM-9
.0 - 0 .0 5 A
Revision: March 2010 2008 QX56

P1752 INPUT CLUTCH SOLENOIDTM-81
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
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 TM-92, "
Diagnosis Procedure".
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 connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to TM-201, "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 TM-80, "
DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value (Ap-
prox.)
I/C SOLE-
NOID Input clutch disengaged. Refer to
TM-9
. 0.6 - 0.8 A
Input clutch engaged. Refer to TM-9
.0 - 0.05 A
Revision: March 2010 2008 QX56

TM-82
< COMPONENT DIAGNOSIS >
P1757 FRONT BRAKE SOLENOID
P1757 FRONT BRAKE SOLENOID
DescriptionINFOID:0000000001604130
Front brake solenoid valve is controlled by the TCM in response to signals sent from the transmission range
switch, output speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then
be shifted to the optimum position.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001604131
On Board Diagn osis LogicINFOID:0000000001604132
• This is an OBD-II self-diagnostic item.
• Diagnostic trouble code “P1757” 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:0000000001604133
• Harness or connectors (The solenoid circuit is open or shorted.)
• Front brake solenoid valve
DTC Confirmation ProcedureINFOID:0000000001604134
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 “TRANSMISSION” with CONSULT-III.
3. Start engine.
4. Drive vehicle and maintain the following conditions for at least 5 consecutive seconds.
ACCELE POS: 1.5/8 - 2.0/8
Selector lever: “D” position
Gear position: 3rd ⇒ 4GR (FR/B ON/OFF)
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving
conditions required for this test.
5. If DTC is detected go to TM-82, "
Diagnosis Procedure".
WITH GST
Follow the procedure “With CONSULT-III”.
Diagnosis ProcedureINFOID:0000000001604135
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.
4. Read out the value of “FR/B SOLENOID” while driving.
Item name Condition Display value (Approx.)
FR/B SOLENOID Front brake engaged. Refer to
TM-9
0.6 - 0.8 A
Front brake disengaged. Refer to TM-9
0 - 0.05 A
Revision: March 2010 2008 QX56

P1757 FRONT BRAKE SOLENOIDTM-83
< COMPONENT DIAGNOSIS >
CEF
G H
I
J
K L
M A
B
TM
N
O P
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 TM-92, "
Diagnosis Procedure".
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 connector.
OK or NG
OK >> Replace the control valve with TCM. Refer to TM-201, "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 TM-82, "
DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value (Ap-
prox.)
FR/B SOLE-
NOID Front brake engaged. Refer to
TM-9
0.6 - 0.8 A
Front brake disengaged. Refer to TM-9
0 - 0.05 A
Revision: March 2010 2008 QX56