Infiniti M45 (Y34). Manual - part 72

DTC P1730 A/T INTERLOCK

AT-173

D

E

F

G

H

I

J

K

L

M

A

B

AT

3. 

CHECK TCM

1.

Check TCM input/output signal. Refer to 

AT-86, "TCM Input/Output Signal Reference Values"

 .

2.

If NG, recheck TCM pin terminals for damage or loose connection with harness connector.

OK or NG

OK

>> INSPECTION END

NG

>> Repair or replace damaged parts.

AT-174

DTC P1731 A/T 1ST ENGINE BRAKING

DTC P1731 A/T 1ST ENGINE BRAKING

PFP:00000

Description

ACS0048K

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

CONSULT-II Reference Value

ACS004PG

On Board Diagnosis Logic

ACS0048L

●

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

●

Diagnostic trouble code “A/T 1ST E/BRAKING” with CONSULT-II or 13th judgement flicker without CON-
SULT-II is detected under the following condition.

–

When TCM does not receive the proper voltage signal from the sensor.

–

When TCM monitors each pressure switch and solenoid monitor value, and detects as irregular when
engine brake of 1st gear acts other than at M1 position.

Possible Cause

ACS0048M

●

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

●

Low coast brake solenoid valve

●

ATF pressure switch 2

DTC Confirmation Procedure

ACS0048N

NOTE:
If “DTC Confirmation Procedure” has been previously conducted, always turn ignition switch OFF and
wait at least 10 seconds before conducting 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.

Maintain the following conditions for at least 2 consecutive sec-
onds.
ENGINE SPEED: 1,200 rpm
Selector lever: “D” position 
Gear position: 1st gear   

5.

If DTC is detected, go to 

AT-176, "Diagnostic Procedure"

 .

Item name

Condition 

Display value

ON OFF SOL

Low coast brake solenoid valve operates.

ON

Other conditions

OFF

ATF PRES SW 2

Low coast brake solenoid valve operates.

ON

Other conditions

OFF

SAT014K

DTC P1731 A/T 1ST ENGINE BRAKING

AT-175

D

E

F

G

H

I

J

K

L

M

A

B

AT

Wiring Diagram — AT — E/BRE

ACS0048O

TCWA0124E

AT-176

DTC P1731 A/T 1ST ENGINE BRAKING

TCM terminals and data are reference value. Measured between each terminal and ground.

Diagnostic Procedure

ACS0048P

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.

Accelerate vehicle in “D” position (1st gear), and confirm the
ON/OFF actuation of the “ATF PRES SW 2” and “ON OFF SOL”.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 2.

Terminal   

No.

Wire 

color

Item

Condition

Data (Approx.)

13

W/L

Low coast brake 
solenoid valve

When 

vehicle 
cruises

When the solenoid valve is operating (when running in M1-1 
gear or M2-2 gear)

Battery voltage

When the solenoid valve is not operating (when running in “D”)

0V

16

W/G

SEL1 (ATF pres-
sure switch 2)

–

–

40

Y/G

DATA BIT1

–

–

Item name

Condition 

Display value

ON OFF SOL

Low coast brake solenoid 
valve operates.

ON

Other conditions

OFF

ATF PRES SW 2

Low coast brake solenoid 
valve operates.

ON

Other conditions

OFF

SCIA4670E