Infiniti M45 (Y34). Manual - part 42

TROUBLE DIAGNOSIS

AT-53

D

E

F

G

H

I

J

K

L

M

A

B

AT

CAUTION:

Run the engine at idle for at least one minute.

Judgement Stall Test

O: Stall speed within standard value position
H: Stall speed higher than standard value
L: Stall speed lower than standard value

Stall test standard value position

LINE PRESSURE TEST 
Line Pressure Test Port

Stall speed:

2,300 - 2,600 rpm

Selector lever position

Expected problem location

“D”, “M”

“R”

Stall rotation 

H

O

●

Forward brake

●

Forward one-way clutch

●

1st one-way clutch

●

3rd one-way clutch

O

H

●

Reverse brake

L

L

●

Engine and torque converter one-way clutch

H

H

●

Line pressure low

Does not shift up “D”, “M” position 1 

→

 2

Slipping in 2nd, 3rd, 4th gears

Direct clutch slippage

Does not shift up “D”, “M” position 2 

→

 3

Slipping in 3rd, 4th, 5th gears

High and low reverse clutch slippage

Does not shift up “D”, “M” position 3 

→

 4

Slipping in 4th, 5th gears

Input clutch slippage

Does not shift up “D”, “M” position 4 

→

 5

Slipping in 5th gear

Front brake slippage

PCIA0017E

AT-54

TROUBLE DIAGNOSIS

Line Pressure Test Procedure

1.

Inspect the amount of engine oil and replenish if necessary.

2.

Drive the car for about 10 minutes to warm it up so that the A/T fluid reaches in range of 50 to 80

°

C (122

to 176

°

F), then inspect the amount of A/T fluid and replenish if necessary.

NOTE:
The automatic fluid temperature rises in range of 50 to 80

°

C (122 to 176

°

F) during 10 minutes of

driving.

3.

After warming up A/T, remove the oil pressure detection plug
and install the oil pressure gauge.

CAUTION:

When using the oil pressure gauge, be sure to use the O-
ring attached to the oil pressure detection plug.

4.

Securely engage the parking brake so that the tires do not turn.

5.

Start the engine, then measure the line pressure at both idle and
the stall speed.

CAUTION:

●

Keep the brake pedal pressed all the way down during
measurement.

●

When measuring the line pressure at the stall speed,
refer to 

AT-52, "STALL TEST"

 . 

6.

After the measurements are complete, install the oil pressure
detection plug and tighten to the regulation torque below.

CAUTION:

●

Do not reuse O-ring.

●

Apply ATF to O-ring.

Line Pressure

SCIA5309E

SCIA1224E

: 7.3 N·m (0.74 kg-m, 65 in-lb)

SAT493G

Engine speed

Line pressure

kPa (kg/cm

2

 , psi)

“R” position

“D”,“ M” positions

At idle speed

392 - 441 (4.0 - 4.5, 57 - 64)

373 - 422 (3.8 - 4.3, 54 - 61)

At stall speed

1,700 - 1,890 (17.3 - 19.3, 247 - 274)

1,310 - 1,500 (13.3 - 15.3, 190 - 218)

TROUBLE DIAGNOSIS

AT-55

D

E

F

G

H

I

J

K

L

M

A

B

AT

Judgement of Line Pressure Test

ROAD TEST 
Description

●

The road test inspects overall performance of the A/T and analyzes possible malfunction causes.

●

The road test is carried out in the following three stages.

1.

Check before engine is started. Refer to 

AT-56

 . 

2.

Check at idle. Refer to 

AT-56

 .

3.

Cruise test

●

Inspect all the items from Part 1 to Part 3. Refer to 

AT-58

 , 

AT-60

 , 

AT-60

 . 

●

Before beginning the road test, check the test procedure and inspection items.

●

Test all inspection items until the symptom is uncovered. Diagnose NG items when all road tests are
complete.

Judgement Possible 

cause

Idle speed

Low for all positions 
(P, R, N, D, M)

Possible causes include malfunctions in the pressure supply system and low oil pump output.
For example

●

Oil pump wear

●

Pressure regulator valve or plug sticking or spring fatigue

●

Oil strainer 

Þ

 oil pump 

Þ

 pressure regulator valve passage oil leak

●

Engine idle speed too low

Only low for a spe-
cific position

Possible causes include an oil pressure leak in a passage or device related to the position after 
the pressure is distributed by the manual valve.

High

Possible causes include a sensor malfunction or malfunction in the line pressure adjustment func-
tion.
For example

●

Accelerator pedal position signal malfunction

●

ATF temperature sensor malfunction

●

Line pressure solenoid malfunction (sticking in “OFF” state, filter clog, cut line)

●

Pressure regulator valve or plug sticking

Stall speed

Oil pressure does 
not rise higher than 
the oil pressure for 
idle.

Possible causes include a sensor malfunction or malfunction in the line pressure adjustment func-
tion.
For example

●

Accelerator pedal position signal malfunction

●

TCM breakdown

●

Line pressure solenoid malfunction (shorting, sticking in“ ON” state)

●

Pressure regulator valve or plug sticking

●

Pilot valve sticking or pilot filter clogged

The pressure rises, 
but does not enter 
the standard posi-
tion.

Possible causes include malfunctions in the pressure supply system and malfunction in the line 
pressure adjustment function.
For example

●

Accelerator pedal position signal malfunction

●

Line pressure solenoid malfunction (sticking, filter clog)

●

Pressure regulator valve or plug sticking

●

Pilot valve sticking or pilot filter clogged

Only low for a spe-
cific position

Possible causes include an oil pressure leak in a passage or device related to the position after 
the pressure is distributed by the manual valve.

AT-56

TROUBLE DIAGNOSIS

Check Before Engine is Started

ACS004HR

1. 

CHECK A/T CHECK INDICATOR LAMP

1.

Park vehicle on level surface.

2.

Move selector lever to “P” position.

3.

Turn ignition switch OFF and wait at least 10 seconds.

4.

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

Does A/T CHECK indicator lamp light up for about 2 seconds?

YES

>> GO TO 2.

NO

>> Stop the road test and go to 

AT-256, "A/T CHECK Indicator Lamp Does Not Come On"

 . 

2. 

CHECK A/T CHECK INDICATOR LAMP

Does A/T CHECK indicator lamp flash for about 8 seconds?

YES

>> For TCM fail-safe mode, carry out self-diagnostics and record all NG items on the diagnostics

worksheet. Refer to 

AT-92

 , 

AT-101

 .

NO

>> 1. Turn ignition switch OFF.

2. Perform self-diagnostics and record all NG items on the diagnostics worksheet. Refer to 

AT-92

, 

AT-101

 .

3. Go to 

AT-56, "Check at Idle"

 .

Check at Idle 

ACS004HS

1. 

CHECK STARTING THE ENGINE

1.

Park vehicle on level surface.

2.

Move selector lever to “P” or “N” position.

3.

Turn ignition switch OFF.

4.

Start engine.

Does the engine start?

YES

>> GO TO 2.

NO

>> Stop the road test and go to 

AT-258, "Engine Cannot Be Started In “P” or “N” Position"

 .

2. 

CHECK STARTING THE ENGINE

1.

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

2.

Move selector lever in “D”, “M” or “R” position.

3.

Start engine.

Does the engine start in any position?

YES

>> Stop the road test and go to 

AT-258, "Engine Cannot Be Started In “P” or “N” Position"

 .

NO

>> GO TO 3.

3. 

CHECK “P” POSITION FUNCTION

1.

Move selector lever to “P” position.

2.

Turn ignition switch OFF.

3.

Release the parking brake.

4.

Push the vehicle forward or backward.

5.

Engage the parking brake.

Does vehicle move when it is pushed forward or backward?

YES

>> Enter a check mark at “Vehicle moves when pushed in “P” position” on the diagnostics worksheet,

then continue the road test.

NO

>> GO TO 4.