Infiniti QX56 (JA60). Manual - part 944

TM-78

< COMPONENT DIAGNOSIS >

P1730 INTERLOCK

P1730 INTERLOCK

Description

INFOID:0000000005148630

Fail-safe function to detect interlock conditions.

On Board Diagnosis Logic

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• This is an OBD-II self-diagnostic item.

• Diagnostic trouble code “P1730 INTERLOCK” with CONSULT-III 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 Cause

INFOID:0000000005148632

• Harness or connectors

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

• Low coast brake solenoid valve

• ATF pressure switch 2

DTC Confirmation Procedure

INFOID:0000000005148633

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-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.

SLCT LVR POSI: “D” position 

5. If DTC is detected, go to 

TM-78, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “With CONSULT-III”.

Judgment of Interlock

INFOID:0000000005148634

• When interlock is judged to be malfunctioning, the vehicle 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 Procedure

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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 for “TRANSMISSION” with CONSULT-III.
 OK or NG

OK

>> GO TO 2.

NG

>> Check low coast brake solenoid valve circuit and function. Refer to 

TM-90, "Diagnosis Proce-

dure"

, 

TM-93, "Diagnosis Procedure"

.

2.

CHECK DTC

Perform “DTC Confirmation Procedure”.

P1730 INTERLOCK

TM-79

< COMPONENT DIAGNOSIS >

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• Refer to 

TM-78, "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-94, "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-172, "Control Valve with TCM and A/T Fluid

Temperature Sensor 2 and Plug"

.

NG

>> Repair or replace damaged parts.

TM-80

< COMPONENT DIAGNOSIS >

P1731 1ST ENGINE BRAKING

P1731 1ST ENGINE BRAKING

Description

INFOID:0000000005148636

Fail-safe function to prevent sudden decrease in speed by engine brake other than at "1" position.

CONSULT-III Reference Value in Data Monitor Mode

INFOID:0000000005148637

On Board Diagnosis Logic

INFOID:0000000005148638

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

• Diagnostic trouble code “P1731 1GR E/BRAKING” with CONSULT-III is detected under the following condi-

tions.

- 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 1GR acts other than at 1 position.

Possible Cause

INFOID:0000000005148639

• Harness or connectors

(The sensor circuit is open or shorted.)

• Low coast brake solenoid valve

• ATF pressure switch 2

DTC Confirmation Procedure

INFOID:0000000005148640

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-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

SLCT LVR POSI: “1” position 

GEAR: 1st

5. If DTC is detected, go to 

TM-80, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000005148641

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 (1GR), and confirm 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

.

ON

Low coast brake disengaged. Refer to 

TM-9

.

OFF

ATF PRES SW 2

Low coast brake engaged. Refer to 

TM-9

.

ON

Low coast brake disengaged. Refer to 

TM-9

.

OFF

P1731 1ST ENGINE BRAKING

TM-81

< COMPONENT DIAGNOSIS >

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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-94, "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-172, "Control Valve with TCM and A/T Fluid

Temperature Sensor 2 and Plug"

.

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

ON OFF SOL

Low coast brake engaged. Refer to 

TM-9

.

ON

Low coast brake disengaged. Refer to 

TM-9

.

OFF

ATF PRES SW 2

Low coast brake engaged. Refer to 

TM-9

.

ON

Low coast brake disengaged. Refer to 

TM-9

.

OFF