2006 INFINITI QX56 ECU

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

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

DTC P1757 FRONT BRAKE SOLENOID VALVEAT-143
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Revision: November 2009 2006 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- 1 4 4 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
FR/B SOLENOID Front brake engaged. Refer to
AT- 2 0
.0.6 - 0.8 A
Front brake disengaged. Refer to AT- 2 0
.0 - 0.05 A
BCIA0030E

DTC P1762 DIRECT CLUTCH SOLENOID VALVEAT-147
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Revision: November 2009 2006 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- 1 4 8 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
D/C SOLENOID Direct clutch disengaged. Refer to
AT- 2 0
.0.6 - 0.8 A
Direct clutch engaged. Refer to AT- 2 0
.0 - 0.05 A
BCIA0030E

DTC P1767 HIGH AND LOW REVERSE CLUTCH SOLENOID VALVEAT-151
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Revision: November 2009 2006 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- 1 5 2 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
Item name Condition Display value (Approx.)
HLR/C SOL High and low reverse clutch disengaged. Refer to
AT- 2 0
. 0.6 - 0.8 A
High and low reverse clutch engaged. Refer to AT- 2 0
. 0 - 0.05 A
BCIA0030E

DTC P1772 LOW COAST BRAKE SOLENOID VALVEAT-155
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G H
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Revision: November 2009 2006 QX56
DTC P1772 LOW COAST BRAKE SOLENOID VALVEPFP:31940
DescriptionECS00CIT
Low coast brake solenoid valve is turned “ON” or “OFF ” 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 ValueECS00CIU
On Board Diagnosis LogicECS00CIV

This is an OBD-II self-diagnostic item.

Diagnostic trouble code “P1772 LC/B SOLENOID/CIRC ” with CONSULT-II is detected when TCM detects
an improper voltage drop when it tries to operate the solenoid valve.
Possible CauseECS00CIW

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

Low coast brake solenoid valve
DTC Confirmation ProcedureECS00CIX
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.
4. Drive vehicle and maintain the following conditions for at least 5 consecutive seconds.
Selector lever: “1” or “2”
Gear position: “1st” or “2nd” gear (LC/B ON/OFF)
5. If DTC is detected, go to AT- 1 5 6 , "
Diagnostic Procedure" .
WITH GST
Follow the procedure “With CONSULT-II”.
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
BCIA0030E

AT-160
DTC P1841 ATF PRESSURE SWITCH 1
Revision: November 20092006 QX56
Diagnostic ProcedureECS00CJA
1. CHECK INPUT SIGNAL
With CONSULT-II
1. Start engine.
2. Select “ECU INPUT SIGNALS ” or “MAIN SIGNALS ” in “DATA
MONITOR ” mode for “A/T ” with CONSULT-II.
3. Drive vehicle in the “D ” position (3rd
4th gear), and confirm
the ON/OFF actuation of the “ATF PRES SW 1”.
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 5 9 , "DTC Confirmation Procedure" .
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
Item name Condition Display value
ATF PRES
SW 1 Front brake engaged. Refer to
AT- 2 0
.ON
Front brake disengaged. Refer to AT- 2 0
.OFF
PCIA0067E