Infiniti FX35 / FX45. Manual - part 46

AT-112

< SERVICE INFORMATION >

DTC P0725 ENGINE SPEED SIGNAL

DTC P0725 ENGINE SPEED SIGNAL

Description

INFOID:0000000001327203

The engine speed signal is sent from the ECM to the TCM with CAN communication.

CONSULT-III Reference Value in Data Monitor Mode

INFOID:0000000001327204

On Board Diagnosis Logic

INFOID:0000000001327205

Diagnostic trouble code “P0725 ENGINE SPEED SIG” with CONSULT-III or 16th judgement flicker without
CONSULT-III is detected when TCM does not receive the ignition signal from ECM during engine cranking or
running.

Possible Cause

INFOID:0000000001327206

Harness or connectors
(ECM to TCM circuit is open or shorted.)

DTC Confirmation Procedure

INFOID:0000000001327207

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-III

1.

Turn ignition switch ON.

2.

Select “SELECTION FROM MENU” in “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III
and check monitor “VHCL/S SE-A/T”, “ACCELE POSI” and “SLCT LVR POSI”.

3.

Touch “START”.

4.

Start engine and maintain the following conditions for at least 10 consecutive seconds.
VHCL/S SE-A/T: 10 km/h (6 MPH) or more
ACCELE POSI: More than 1.0/8
SLCT LVR POSI: “D” position 

5.

If DTC is detected, go to 

AT-112, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000001327208

1.

CHECK CAN COMMUNICATION LINE

 With CONSULT-III

• Perform the self-diagnosis.

 Without CONSULT-III

• Perform the self-diagnosis. Refer to 

AT-91, "Diagnosis Procedure without CONSULT-III"

.

Is a malfunction in the CAN communication indicated in the results?

YES

>> Check CAN communication line. Refer to 

AT-94

.

NO

>> GO TO 2.

2.

CHECK DTC WITH TCM

 With CONSULT-III

1.

Start engine.

2.

Select “ECU INPUT SIGNALS” in “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.

Item name

Condition 

Display value

ENGINE SPEED

Engine running

Closely matches the tachometer reading.

DTC P0725 ENGINE SPEED SIGNAL

AT-113

< SERVICE INFORMATION >

D

E

F

G

H

I

J

K

L

M

A

B

AT

N

O

P

3.

While monitoring engine speed, check for engine speed change corresponding to wide-open throttle posi-
tion signal.

OK or NG

OK

>> GO TO 3.

NG

>> Check the ignition signal circuit. Refer to 

EC-569

 (for VQ35DE) or 

EC-1166

 (for VK45DE)

3.

CHECK DTC

Perform 

AT-112, "DTC Confirmation Procedure"

.

OK or NG

OK

>> INSPECTION END

NG

>> GO TO 4.

4.

CHECK TCM POWER SUPPLY AND GROUND CIRCUIT

Check TCM power supply and ground circuit. Refer to 

AT-160

.

OK or NG

OK

>> GO TO 5.

NG

>> Repair or replace damaged parts.

5.

DETECT MALFUNCTIONING ITEM

Check 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 

AT-215, "Control Valve with TCM and A/T Fluid Tem-

perature Sensor 2"

.

NG

>> Repair or replace damaged parts.

Item name

Condition 

Display value

ENGINE SPEED

Engine running

Closely matches the tachometer reading.

AT-114

< SERVICE INFORMATION >

DTC P0731 A/T 1ST GEAR FUNCTION

DTC P0731 A/T 1ST GEAR FUNCTION

Description

INFOID:0000000001375112

This malfunction is detected when the A/T does not shift into 1st gear position as instructed by TCM. This is
not only caused by electrical malfunction (circuits open or shorted) but also by mechanical malfunction such
as control valve sticking, improper solenoid valve operation.

On Board Diagnosis Logic

INFOID:0000000001375113

Diagnostic trouble code “P0731 A/T 1ST GR FNCTN” with CONSULT-III or 18th judgment flicker without CON-
SULT-III is detected when TCM detects any inconsistency in the actual gear ratio.

Possible Cause

INFOID:0000000001375114

• Harness or connectors 

(Solenoid circuits are open or shorted.)

• Input clutch solenoid valve
• Front brake solenoid valve
• Direct clutch solenoid valve
• High and low reverse clutch solenoid valve
• Each clutch
• Hydraulic control circuit

DTC Confirmation Procedure

INFOID:0000000001375115

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-III

1.

Start the engine and select “DATA MONITOR” mode for “TRANSMISSION” with CONSULT-III.

2.

Make sure that “ATF TEMP 1” is within the following range.
ATF TEMP 1: 20

°

C – 140

°

C

If out of range, drive vehicle to warm ATF or stop engine to cool ATF.

3.

Select “1ST GR FNCTN P0731” of “DTC WORK SUPPORT” mode for “TRANSMISSION” with CON-
SULT-III.

4.

Drive vehicle and maintain the following conditions.
VEHICLE SPEED: 10 km/h (6 MPH) or more
ACCELE POSI: 0.6/8 or more
ENGINE SPEED: TURBINE REV 

−

 50 rpm or more

TURBINE REV: 300 rpm or more
GEAR: “1” position
MANU MODE SW: ON

5.

Keep the current driving status for at least 5 consecutive seconds if CONSULT-III screen changes from
“OUT OF CONDITION” to “TESTING”.

CAUTION:

If “TESTING” does not appear on CONSULT-III for a long time, select “SELF-DIAG RESULTS”. In
case a 1st trip DTC other than P0731 is shown, refer to “

AT-84, "CONSULT-III Function (TRANSMIS-

SION)"

”.

If “COMPLETED RESULT NG” is detected, go to 

AT-115, "Diagnosis Procedure"

.

If “STOP VEHICLE” is detected, go to the following step.

6.

Stop vehicle.

7.

Drive vehicle in “D” position allowing it to shift from 1st to 5th gear and check shift timing and shift shock.

-

Touch “OK” to complete the inspection when normally shifted from the 1st to 5th gear.

-

Touch “NG” when an unusual shift shock, etc. occurs in spite of shifting from the 1st to 5th gear. Go to 

AT-

49, "Inspections Before Trouble Diagnosis"

.

-

Perform 

AT-84, "CONSULT-III Function (TRANSMISSION)"

 when not shifted from the 1st to 5th gear.

(Neither “OK” nor “NG” are indicated.)

DTC P0731 A/T 1ST GEAR FUNCTION

AT-115

< SERVICE INFORMATION >

D

E

F

G

H

I

J

K

L

M

A

B

AT

N

O

P

Diagnosis Procedure

INFOID:0000000001375116

1.

CHECK CAN COMMUNICATION LINE

 With CONSULT-III

• Perform self-diagnosis.

 Without CONSULT-III

• Perform self-diagnosis. Refer to 

AT-91, "Diagnosis Procedure without CONSULT-III"

.

Is a malfunction in the CAN communication indicated in the results?

YES

>> Check CAN communication line. Refer to 

AT-124

.

NO

>> GO TO 2.

2.

CHECK TCM POWER SUPPLY AND GROUND CIRCUIT

Check TCM power supply and ground circuit. Refer to 

AT-126

.

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace damaged parts.

3.

DETECT MALFUNCTION ITEM

Check A/T assembly harness connector pin terminals for damage or loose connection with harness connector.

OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace damaged parts.

4.

REPLACE CONTROL VALVE WITH TCM

1.

Replace control valve with TCM. Refer to 

AT-215, "Control Valve with TCM and A/T Fluid Temperature

Sensor 2"

.

2.

Perform 

AT-114, "DTC Confirmation Procedure"

.

OK or NG

OK

>> INSPECTION END

NG

>> Confirm malfunction phenomena by “ROAD TEST” to repair malfunctioning part. Refer to 

AT-49,

"Inspections Before Trouble Diagnosis"

.