Nissan Quest E52. Manual - part 1224

TM-126

< DTC/CIRCUIT DIAGNOSIS >

[CVT: RE0F09B]

P1777 STEP MOTOR

Is the inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-42, "Intermittent Incident"

.

NO

>> GO TO 2.

2.

CHECK STEP MOTOR

1.

Disconnect the CVT unit connector.

2.

Check the step motor. Refer to 

TM-126, "Component Inspection (Step Motor)"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Replace the transaxle assembly due to malfunction in the step motor. Refer to 

TM-174, "Removal

and Installation"

.

3.

CHECK HARNESS BETWEEN TCM AND CVT UNIT

1.

Check the continuity between TCM harness connector terminals and CVT unit harness connector termi-
nals.

2.

Check the continuity between TCM harness connector terminals and ground.

Is the inspection result normal?

YES

>> Check intermittent incident. Refer to 

GI-42, "Intermittent Incident"

.

NO

>> Repair or replace damaged parts.

Component Inspection (Step Motor)

INFOID:0000000009650203

1.

CHECK STEP MOTOR

1.

Check the resistance between CVT unit connector terminals.

2.

Check the resistance between CVT unit connector terminals and ground.

TCM

—

Resistance (Approx.)

Connector

Terminal

F23

27

Ground

15.0 

Ω

28

29

30

TCM

CVT unit

Continuity

Connector

Terminal

Connector

Terminal

F23

27

F24

9

Existed

28

8

29

7

30

6

TCM

—

Continuity

Connector

Terminal

F23

27

Ground

Not existed

28

29

30

CVT unit

Resistance (Approx.)

Terminal

6

7

30.0 

Ω

8

9

P1777 STEP MOTOR

TM-127

< DTC/CIRCUIT DIAGNOSIS >

[CVT: RE0F09B]

C

E

F

G

H

I

J

K

L

M

A

B

TM

N

O

P

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace the transaxle assembly due to malfunction in the step motor. Refer to 

TM-174, "Removal

and Installation"

.

CVT unit

—

Resistance (Approx.)

terminal

6

Ground

15.0 

Ω

7

8

9

TM-128

< DTC/CIRCUIT DIAGNOSIS >

[CVT: RE0F09B]

P1778 STEP MOTOR

P1778 STEP MOTOR

Description

INFOID:0000000009650204

• The step motor changes the step by turning 4 coils ON/OFF according to the signal from TCM. As a result,

the flow of line pressure to primary pulley is changed and pulley ratio is controlled.

• This diagnosis item is detected when the electrical system is OK, but the mechanical system is NG.
• This diagnosis item is detected when the state of the changing of the speed mechanism in the unit does not

operate normally.

DTC Logic

INFOID:0000000009650205

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

CAUTION:

• Always drive vehicle at a safe speed.
• Check primary speed and vehicle speed before perform “DTC CONFIRMATION PROCEDURE”.
• If hi-geared fixation occurred, go to 

TM-86, "Diagnosis Procedure"

.

1.

PRECONDITIONING

If “DTC CONFIRMATION PROCEDURE” has been previously conducted, always turn ignition switch OFF and
wait at least 10 seconds before conducting the next test.

>> GO TO 2.

2.

CHECK DTC DETECTION

With CONSULT

1.

Start the engine.

2.

Warm up the engine. [Set the CVT fluid to 20

°

C (68

°

F) or more.]

NOTE:
When the ambient temperature is 20

°

C (68

°

F), the CVT fluid usually increases to 50 to 80

°

C (122 to

176

°

F) with driving in an urban area for approximately 10 minutes.

3.

Maintain the following conditions for at least 30 seconds.

With GST

Follow the procedure “With CONSULT”.

Is “P1778” detected?

YES

>> Go to 

TM-128, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000009650206

1.

CHECK STEP MOTOR SYSTEM

DTC

Trouble diagnosis name

DTC detection condition

Possible cause

P1778

Step Motor Circuit Intermit-
tent

When below diagnosis conditions are met, the difference 
between actual primary speed and command primary 
speed calculated by shift control logic exceeds 1,000 rpm 
and keeps the status for 5 seconds or more
• Diagnosis Conditions
- Selector lever: “D” position
- Vehicle speed: 11 km/h (7 MPH) or more
- Accelerator pedal position: 1.1/8
- Engine speed: 450 rpm or more
- CVT fluid temperature: 20

°

C – 180

°

C (68

°

F – 356

°

F)

Step motor

Selector lever

: “D” position 

Accelerator pedal position

: 1.1/8 or more

Vehicle speed

: 20 km/h (13 MPH) or more

P1778 STEP MOTOR

TM-129

< DTC/CIRCUIT DIAGNOSIS >

[CVT: RE0F09B]

C

E

F

G

H

I

J

K

L

M

A

B

TM

N

O

P

Check the step motor system. Refer to 

TM-125, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace damaged parts.

2.

CHECK PRIMARY SPEED SENSOR SYSTEM

Check the primary speed sensor system. Refer to 

TM-86, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace damaged parts.

3.

CHECK SECONDARY SPEED SENSOR SYSTEM

Check the secondary speed sensor system. Refer to 

TM-88, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace damaged parts.

4.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> Replace the transaxle assembly. Refer to 

TM-174, "Removal and Installation"

.

NO

>> Repair or replace damaged parts.