2006 INFINITI QX56 engine

AT-132
DTC P1721 VEHICLE SPEED SENSOR MTR
Revision: November 20092006 QX56
DTC P1721 VEHICLE SPEED SENSOR MTRPFP:24814
DescriptionECS00CGZ
The vehicle speed sensor·MTR signal is transmitted from combination meter to TCM by CAN communication
line. The signal functions as an auxiliary device to the revolution sensor when it is malfunctioning. The TCM
will then use the vehicle speed sensor ·MTR signal.
CONSULT-II Reference ValueECS00CH0
On Board Diagnosis LogicECS00CH1

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

Diagnostic trouble code “P1721 VHE SPD SE ·MTR ” with CONSULT-II is detected when TCM does not
receive the proper vehicle speed sensor MTR signal (input by CAN communication) from combination
meter.
Possible CauseECS00CH2
Harness or connectors
(The sensor circuit is open or shorted.)
DTC Confirmation ProcedureECS00CH3
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 “A/T” with CONSULT-II.
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 AT- 1 3 3 , "
Diagnostic Procedure" .
Item name Condition Display value (km/h)
VHCL/S SE ·MTR During driving Approximately matches the speedometer reading.
BCIA0030E

DTC P1721 VEHICLE SPEED SENSOR MTRAT-133
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Revision: November 2009 2006 QX56
Diagnostic ProcedureECS00CH4
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer AT- 8 6 , "
SELF-DIAGNOSTIC RESULT MODE" .
Is a malfunction in the CAN communication indicated in the results?
YES >> Check CAN communication line. Refer to AT- 9 6 , "DTC U1000 CAN COMMUNICATION LINE" .
NO >> GO TO 2.
2. CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for
“A/T ” with CONSULT-II.
3. Drive vehicle and read out the value of “VHCL/S SE·MTR ”.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3. CHECK COMBINATION METERS
Check combination meter. Refer to DI-17, "
How to Proceed With Trouble Diagnosis" .
OK or NG
OK >> GO TO 4.
NG >> Repair or replace damaged parts.
4. CHECK DTC
Perform “DTC Confirmation Procedure ”.

Refer to AT- 1 3 2 , "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 . AT- 1 6 7 , "
MAIN POWER SUPPLY AND GROUND CIR-
CUIT"
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 connec-
tor.
OK or NG
OK >> Replace the control valve with TCM. Refer to AT- 2 3 0 , "Control Valve With TCM and A/T Fluid
Temperature Sensor 2" .
NG >> Repair or replace damaged parts.
Item name Condition Display value (Approx.)(km/h)
VHCL/S SE ·MTR During driving Approximately matches the
speedometer reading.
SCIA2148E

AT-134
DTC P1730 A/T INTERLOCK
Revision: November 20092006 QX56
DTC P1730 A/T INTERLOCKPFP:00000
DescriptionECS00CH5

Fail-safe function to detect interlock conditions.
On Board Diagnosis LogicECS00CH6

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P1730 A/T INTERLOCK ” with CONSULT-II is detected when TCM does not
receive the proper voltage signal from the sensor and switch.

TCM monitors and compares gear position and conditions of each ATF pressure switch when gear is
steady.
Possible CauseECS00CH7

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

Low coast brake solenoid valve

ATF pressure switch 2
DTC Confirmation ProcedureECS00CH8
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. Drive vehicle and maintain the following conditions for at least 2 consecutive seconds.
Selector lever: “D” position
5. If DTC is detected, go to AT- 1 3 5 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
BCIA0030E

DTC P1731 A/T 1ST ENGINE BRAKINGAT-137
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Revision: November 2009 2006 QX56
DTC P1731 A/T 1ST ENGINE BRAKINGPFP:00000
DescriptionECS00CHB
Fail-safe function to prevent sudden decrease in speed by engine brake other than at "1" position.
CONSULT-II Reference ValueECS00CHC
On Board Diagnosis LogicECS00CHD

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

Diagnostic trouble code “P1731 A/T 1ST E/BRAKING ” with CONSULT-II is detected under the following
conditions.
–When TCM does not receive the proper voltage signal from the sensor.
–When TCM monitors each ATF pressure switch and solenoid monitor value, and detects as irregular when
engine brake of 1st gear acts other than at 1 position.
Possible CauseECS00CHE

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

Low coast brake solenoid valve

ATF pressure switch 2
DTC Confirmation ProcedureECS00CHF
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 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. 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 AT- 1 3 8 , "
Diagnostic Procedure" .
Item name Condition Display value
ON OFF SOL Low coast brake engaged. Refer to
AT- 2 0
.O N
Low coast brake disengaged. Refer to AT- 2 0
.O FF
ATF PRES SW 2 Low coast brake engaged. Refer to
AT- 2 0
.O N
Low coast brake disengaged. Refer to AT- 2 0
.O FF
BCIA0030E

AT-138
DTC P1731 A/T 1ST ENGINE BRAKING
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CHG
1. CHECK INPUT SIGNALS
With CONSULT-II
1. Start the engine.
2. Select “SELECTION FROM MENU” in “DATA MONITOR” for
"A/T" with CONSULT-II"
3. Drive vehicle in the “1 ” position (1st gear), and confirm the ON/
OFF actuation of “ATF PRES SW 2 ” and "ON OFF SOL".
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 7 , "
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- 2 3 0 , "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- 1 3 7 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ON OFF
SOL Low coast brake engaged. Refer to
AT- 2 0
.ON
Low coast brake disengaged. Refer to AT- 2 0
.OFF
ATF PRES
SW 2 Low coast brake engaged. Refer to
AT- 2 0
.ON
Low coast brake disengaged. Refer to AT- 2 0
.OFF
PCIA0067E

DTC P1752 INPUT CLUTCH SOLENOID VALVEAT-139
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Revision: November 2009 2006 QX56
DTC P1752 INPUT CLUTCH SOLENOID VALVEPFP:31940
DescriptionECS00CHH
Input clutch solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehicle
speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the
optimum position.
CONSULT-II Reference ValueECS00CHI
On Board Diagnosis LogicECS00CHJ

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P1752 I/C 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 CauseECS00CHK

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

Input clutch solenoid valve
DTC Confirmation ProcedureECS00CHL
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 “A/T” with CONSULT-II.
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
4th Gear (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 AT- 1 4 0 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
I/C SOLENOID Input clutch disengaged. Refer to
AT- 2 0
.0.6 - 0.8 A
Input clutch engaged. Refer to AT- 2 0
.0 - 0.05 A
BCIA0030E

AT-140
DTC P1752 INPUT CLUTCH SOLENOID VALVE
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CHM
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 “I/C 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 7 , "
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- 2 3 0 , "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- 1 3 9 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
(Approx.)
I/C SOLE-
NOID Input clutch disengaged. Refer to
AT- 2 0
. 0.6 - 0.8 A
Input clutch engaged. Refer to AT- 2 0
. 0 - 0.05 ASCIA4793E

DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTIONAT-141
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Revision: November 2009 2006 QX56
DTC P1754 INPUT CLUTCH SOLENOID VALVE FUNCTIONPFP:31940
DescriptionECS00CHN

Input clutch solenoid valve is controlled by the TCM in response to signals sent from the PNP switch, vehi-
cle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be
shifted to the optimum position.

This is not only caused by electrical malfunction (circuits open or shorted) but also by mechanical mal-
function such as control valve sticking, improper solenoid valve operation.
CONSULT-II Reference ValueECS00CHO
On Board Diagnosis LogicECS00CHP

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P1754 I/C SOLENOID FNCTN” with CONSULT-II is detected under the following
conditions.
–When TCM detects that actual gear ratio is irregular, and relation between gear position and condition of
pressure switch 3 is irregular during depressing accelerator pedal. (Other than during shift change)
–When TCM detects that relation between gear position and condition of ATF pressure switch 3 is irregular
during releasing accelerator pedal. (Other than during shift change)
Possible CauseECS00CHQ

Harness or connectors
(The solenoid and switch circuits are open or shorted.)

Input clutch solenoid valve

ATF pressure switch 3
DTC Confirmation ProcedureECS00CHR
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.
2. Accelerate vehicle to maintain the following conditions.
ACCELE POSI: 1.5/8 - 2.0/8
Selector lever: “D” position
Gear position: 3rd
4th Gear (I/C ON/OFF)
Driving location: Driving the vehicle uphill (increased
engine load) will help maintain the driving conditions
required for this test.
3. Perform step “2” again.
4. Turn ignition switch “OFF”, then perform step “1” to “3 ” again.
5. Check “SELF-DIAG RESULTS ” mode for “A/T” with CONSULT-
II. If DTC (P1754) is detected, refer to AT- 1 4 2 , "
Diagnostic Procedure" .
If DTC (P1752) is detected, go to AT- 1 4 0 , "
Diagnostic Procedure" .
If DTC (P1843) is detected, go to AT- 1 6 2 , "
Diagnostic Procedure" .
Item nameCondition Display value (Approx.)
I/C SOLENOID Input clutch disengaged. Refer to
AT- 2 0
.0.6 - 0.8 A
Input clutch engaged. Refer to AT- 2 0
.0 - 0.05 A
ATF PRES SW 3 Input clutch engaged. Refer to
AT- 2 0
.ON
Input clutch disengaged. Refer to AT- 2 0
.OFF
BCIA0030E