2005 INFINITI QX4 ECU

DTC P1721 VEHICLE SPEED SENSOR MTR
AT-133
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Revision: October 20052005 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 4 , "
Diagnostic Procedure" .
Item name Condition Display value (km/h)
VHCL/S SE·MTR During driving Approximately matches the speedometer reading.
BCIA0030E

AT-134
DTC P1721 VEHICLE SPEED SENSOR MTR
Revision: October 20052005 QX56
Diagnostic ProcedureECS00CH4
1. CHECK CAN COMMUNICATION LINE
Perform the self-diagnosis. Refer 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-95, "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-133, "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-168, "
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-231, "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 drivingApproximately matches the
speedometer reading.
SCIA2148E

DTC P1730 A/T INTERLOCK
AT-135
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Revision: October 20052005 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 6 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
BCIA0030E

AT-138
DTC P1731 A/T 1ST ENGINE BRAKING
Revision: October 20052005 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-139, "
Diagnostic Procedure" .
Item name Condition Display value
ON OFF SOLLow coast brake engaged. Refer to AT- 1 9
.ON
Low coast brake disengaged. Refer to AT- 1 9
.OFF
ATF PRES SW 2Low coast brake engaged. Refer to AT- 1 9
.ON
Low coast brake disengaged. Refer to AT- 1 9
.OFF
BCIA0030E

AT-140
DTC P1752 INPUT CLUTCH SOLENOID VALVE
Revision: October 20052005 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-141, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
I/C SOLENOIDInput clutch disengaged. Refer to AT- 1 9
.0.6 - 0.8 A
Input clutch engaged. Refer to AT- 1 9
. 0 - 0.05 A
BCIA0030E

AT-144
DTC P1757 FRONT BRAKE SOLENOID VALVE
Revision: October 20052005 QX56
DTC P1757 FRONT BRAKE SOLENOID VALVEPFP:31940
DescriptionECS00CHT
Front brake 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 ValueECS00CHU
On Board Diagnosis LogicECS00CHV

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P1757 FR/B 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 CauseECS00CHW

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

Front brake solenoid valve
DTC Confirmation ProcedureECS00CHX
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 (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 AT-145, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
FR/B SOLENOIDFront brake engaged. Refer to AT- 1 9
.0.6 - 0.8 A
Front brake disengaged. Refer to AT- 1 9
. 0 - 0.05 A
BCIA0030E

AT-148
DTC P1762 DIRECT CLUTCH SOLENOID VALVE
Revision: October 20052005 QX56
DTC P1762 DIRECT CLUTCH SOLENOID VALVEPFP:31940
DescriptionECS00CI5
Direct 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 ValueECS00CI6
On Board Diagnosis LogicECS00CI7

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P1762 D/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 CauseECS00CI8

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

Direct clutch solenoid valve
DTC Confirmation ProcedureECS00CI9
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: 1st

2nd Gear (D/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-149, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
D/C SOLENOIDDirect clutch disengaged. Refer to AT-1 9
. 0.6 - 0.8 A
Direct clutch engaged. Refer to AT-1 9
. 0 - 0.05 A
BCIA0030E

AT-152
DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVE
Revision: October 20052005 QX56
DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVEPFP:31940
DescriptionECS00CIH
High and low reverse 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 ValueECS00CII
On Board Diagnosis LogicECS00CIJ

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P1767 HLR/C SOL/CIRC” with CONSULT-II or 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 CauseECS00CIK

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

High and low reverse clutch solenoid valve
DTC Confirmation ProcedureECS00CIL
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: 2nd

3rd Gear (HLR/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-153, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
HLR/C SOLHigh and low reverse clutch disengaged. Refer to AT- 1 9
.0.6 - 0.8 A
High and low reverse clutch engaged. Refer to AT- 1 9
. 0 - 0.05 A
BCIA0030E