Infiniti Q45. Manual - part 56

DTC P1730 A/T INTERLOCK

AT-137

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Judgement of A/T Interlock

NCS000XC

When A/T Interlock is judged to be malfunctioning, the vehicle should be fixed in 2nd gear, and should be set
in a condition in which it can travel.
When one of the following fastening patterns is detected, the fail-safe function in correspondence with the indi-
vidual pattern should be performed.

NOTE:
When the vehicle is driven fixed in 2nd gear, a turbine revolution sensor malfunction is displayed, but
this is not a turbine revolution sensor malfunction.

A/T INTERLOCK COUPLING PATTERN TABLE

●

: NG, X: OK

Diagnostic Procedure

NCS000XD

1. 

CHECK SELF-DIAGNOSTIC RESULTS

 With CONSULT-II

1.

Drive vehicle.

2.

Stop vehicle and turn ignition switch OFF.

3.

Turn ignition switch ON. (Do not start engine.)

4.

Select “SELF-DIAG RESULTS” mode for “A/T” with CONSULT-
II.

 Without CONSULT-II

1.

Drive vehicle.

2.

Stop vehicle and turn ignition switch OFF.

3.

Turn ignition switch ON. (Do not start engine.)

4.

Perform self-diagnosis. Refer to 

AT-97, "TCM SELF-DIAGNOSTIC PROCEDURE (NO TOOLS)"

 .

 OK or NG

OK

>> GO TO 2.

NG

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

AT-157, "DTC P1772 LOW

COAST BRAKE SOLENOID VALVE"

 , 

AT-159, "DTC P1774 LOW COAST BRAKE SOLENOID

VALVE FUNCTION"

 .

2. 

CHECK DTC

Perform “DTC Confirmation Procedure”. Refer to 

AT-136, "DTC Confirmation Procedure"

 .

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 3.

Gear position

ATF pressure switch output

Fail-safe 

function

Clutch pressure output pattern after fail-safe func-

tion

SW3 

(I/C)

SW6 

(HLR/

C)

SW5 

(D/C)

SW1 

(FR/B)

SW2 

(LC/B)

I/C

HLR/C

D/C

FR/B

LC/B

L/U

A/T interlock 
coupling pat-
tern

3rd

–

X

X

–

●

Held in 

2nd gear

OFF

OFF

ON

OFF

OFF

OFF

4th

–

X

X

–

●

Held in 

2nd gear

OFF

OFF

ON

OFF

OFF

OFF

5th

X

X

–

X

●

Held in 

2nd gear

OFF

OFF

ON

OFF

OFF

OFF

BCIA0031E

AT-138

DTC P1730 A/T INTERLOCK

3. 

CHECK TCM POWER SUPPLY AND GROUND CIRCUIT

Check TCM power supply and ground circuit. Refer to 

AT-173, "MAIN POWER SUPPLY AND GROUND CIR-

CUIT"

 .

OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace damaged parts.

4. 

DETECT MALFUNCTIONING ITEM

Check the following.

●

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-225, "Control Valve with TCM and A/T Fluid Tem-

perature Sensor 2"

 .

NG

>> Repair or replace damaged parts.

DTC P1731 A/T 1ST ENGINE BRAKING

AT-139

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DTC P1731 A/T 1ST ENGINE BRAKING

PFP:00000

Description

NCS000XE

Fail-safe function to prevent sudden decrease in speed by engine brake other than at M1 position.

CONSULT-II Reference Value

NCS000XF

On Board Diagnosis Logic

NCS000XG

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

●

Diagnostic trouble code “P1731 A/T 1ST E/BRAKING” with CONSULT-II or 13th judgement flicker without
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 M1 position.

Possible Cause

NCS000XH

●

Harness or connectors
(Sensor circuit is open or shorted.)

●

Low coast brake solenoid valve

●

ATF pressure switch 2

DTC Confirmation Procedure

NCS000XI

CAUTION:

●

Always drive vehicle at a safe speed.

●

Be careful not to rev engine into the red zone on the tachometer.

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 “SELECTION FROM MENU” in “DATA MONITOR” mode
for “A/T” with CONSULT-II and check monitor “ENGINE
SPEED”, “MANU MODE SW” and “GEAR”.

3.

Touch “START”.

4.

Start engine.

5.

Drive vehicle and maintain the following conditions for at least 2
consecutive seconds.
ENGINE SPEED: 1,200 rpm
MANU MODE SW: ON 
GEAR: “1” position   

6.

If DTC is detected, go to 

AT-140, "Diagnostic Procedure"

 .

Item name

Condition 

Display value

ON OFF SOL

Low coast brake engaged. Refer to 

AT-19

 

.

ON

Low coast brake disengaged. Refer to 

AT-19

 

.

OFF

ATF PRES SW 2

Low coast brake engaged. Refer to 

AT-19

 

.

ON

Low coast brake disengaged. Refer to 

AT-19

 

.

OFF

BCIA0031E

AT-140

DTC P1731 A/T 1ST ENGINE BRAKING

Diagnostic Procedure

NCS000XJ

1. 

CHECK INPUT SIGNALS

 With CONSULT-II

1.

Start engine.

2.

Select “SELECTION FROM MENU” in “DATA MONITOR” mode
for “A/T” with CONSULT-II.

3.

Drive vehicle in the “M” 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-173, "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.

●

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-225, "Control Valve with TCM and A/T Fluid Tem-

perature Sensor 2"

 .

NG

>> Repair or replace damaged parts.

4. 

CHECK DTC

Perform “DTC Confirmation Procedure”. Refer to 

AT-139, "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-19

 

.

ON

Low coast brake disengaged. Refer to 

AT-19

 

.

OFF

ATF PRES 
SW 2

Low coast brake engaged. Refer to 

AT-19

 

.

ON

Low coast brake disengaged. Refer to 

AT-19

 

.

OFF

SCIA4670E