Nissan Murano Z51 (2012 year). Manual - part 89

STC-4

< SYSTEM DESCRIPTION >

EPS SYSTEM

• The valve driving voltage to control the power steering solenoid

valve varies according to the vehicle speed.

OPERATION PRINCIPLE

During Parking (When Turning The Steering Wheel To The Right.)

1.

Power steering solenoid valve is closed while a vehicle is stopped.

2.

Pinion “1R”, “2R” and “3R” are closed depending on steering torque of steering wheel.

3.

Oil pressure “P” in the gear housing assembly is the sum of oil pressures occurred in “2R” and “3R”. This
results in a light steering force because of high pressure.

During High-speed Operation

1.

Power steering solenoid valve is opened during high-speed operation.

2.

Pinion “1R”, “2R” and “3R” are closed depending on steering torque of steering wheel.

3.

Oil pressure “2R” does not occur because the power steering solenoid valve is on full throttle.

4.

Oil pressure “P” in the gear housing assembly includes only oil pressure occurred in “3R” and results in a
heavy steering force.

JSGIA0374GB

JSGIA0020GB

JSGIA0021GB

Revision: 2013 February

2012 MURANO

EPS SYSTEM

STC-5

< SYSTEM DESCRIPTION >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

Component Parts Location

INFOID:0000000007540091

Component Description

INFOID:0000000007540092

1.

Power steering solenoid valve

2.

Power steering control unit

A.

Steering gear assembly

B.

Glove box assembly removed

: Vehicle front

JSGIA0301ZZ

Component parts

Reference/Function

Power steering control unit

• Signals from various sensors control the driving voltage to the power steering solenoid valve.
• The power steering control unit controls the driving voltage to the power steering solenoid valve 

for maintaining the power steering assist force when the fail-safe function is activated. (The en-
gine speed signals control EPS system if any vehicle speed signal error is detected.)

Combination meter

STC-11, "Description"

ECM

STC-9, "Description"

Power steering solenoid valve

STC-7, "Description"

Revision: 2013 February

2012 MURANO

STC-6

< DTC/CIRCUIT DIAGNOSIS >

POWER SUPPLY AND GROUND CIRCUIT

DTC/CIRCUIT DIAGNOSIS

POWER SUPPLY AND GROUND CIRCUIT

Description

INFOID:0000000007540093

Power supply to EPS system

Diagnosis Procedure

INFOID:0000000007540094

1.

CHECK POWER SUPPLY

1.

Turn the ignition switch OFF.

2.

Disconnect power steering control unit harness connector.

3.

Check voltage between power steering control unit harness connector and ground.

4.

Turn the ignition switch ON.

CAUTION:

Never start the engine.

5.

Check voltage between power steering control unit harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>>

Check the following. If any items are damaged, repair or replace damaged parts.

• 10A fuses (#3) open
- Harness for short or open between ignition switch and power steering control unit harness con-

nector No. 3 terminal.

- Ignition switch. Refer to 

PCS-65, "Component Inspection"

.

2.

CHECK GROUND CIRCUIT

1.

Turn the ignition switch OFF.

2.

Check continuity between power steering control unit harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair open circuit or short to power in harness or connectors.

3.

CHECK TERMINALS AND HARNESS CONNECTORS

Check power steering control unit pin terminals for damage or loose connection with harness connector.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Repair or replace damaged parts.

Power steering control unit

—

Voltage

(Approx.)

Connector

Terminal

M61

3 Ground

0 

V

Power steering control unit

—

Voltage

(Approx.)

Connector

Terminal

M61

3 Ground

Battery 

voltage

Power steering control unit

—

Continuity

Connector

Terminal

M61

6 Ground

Existed

Revision: 2013 February

2012 MURANO

POWER STEERING SOLENOID VALVE

STC-7

< DTC/CIRCUIT DIAGNOSIS >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

POWER STEERING SOLENOID VALVE

Description

INFOID:0000000007540095

Power steering solenoid valve controls the power steering oil pressure in the gear housing assembly.

Diagnosis Procedure

INFOID:0000000007540096

1.

CHECK POWER STEERING SOLENOID VALVE SIGNAL

Check voltage between power steering control unit harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> GO TO 2.

2.

CHECK HARNESS BETWEEN POWER STEERING SOLENOID VALVE AND POWER STEERING CON-

TROL UNIT

1.

Turn the ignition switch OFF.

2.

Disconnect power steering solenoid valve harness connector.

3.

Disconnect power steering control unit harness connector.

4.

Check the continuity between power steering solenoid valve harness connector and the power steering
control unit harness connector.

5.

Check continuity between power steering control unit harness connector and ground.

Is the inspection result normal?

 YES

>> GO TO 3.

 NO

>> Repair or replace damaged parts.

3.

CHECK POWER STEERING SOLENOID VALVE

Check power steering solenoid valve. Refer to 

STC-8, "Component Inspection"

.

Is the inspection result normal?

 YES

>> GO TO 4.

 NO

>> Replace gear-sub assembly. Refer to 

ST-44, "Exploded View"

 (With heated steering wheel), 

ST-

85, "Exploded View"

 (Without heated steering wheel).

4.

CHECK TERMINALS AND HARNESS CONNECTORS

• Check power steering control unit pin terminals for damage or loose connection with harness connector.
• Check power steering solenoid valve pin terminals for damage or loose connection with harness connector.

Is the inspection result normal?

Power steering control unit

—

Condition

Voltage

(Approx.)

Connector

Terminal

M61

 1 

Ground

Vehicle speed: 0 km/h (0 MPH)
(Engine is running)

4.4 – 6.6 V

Vehicle speed: 100 km/h (62 MPH)

2.4 – 3.6 V

Power steering solenoid valve

Power steering control unit

Continuity

Connector

Terminal

Connector

Terminal

E52

1

M61

1

Existed

E52

2

M61

5

Existed

Power steering control unit

—

Continuity

Connector

Terminal

M61

1

Ground

Not existed

M61

5

Revision: 2013 February

2012 MURANO

STC-8

< DTC/CIRCUIT DIAGNOSIS >

POWER STEERING SOLENOID VALVE

YES

>> INSPECTION END

NO

>> Repair or replace damaged parts.

Component Inspection

INFOID:0000000007540097

1.

CHECK POWER STEERING SOLENOID VALVE

1.

Turn the ignition switch OFF.

2.

Disconnect power steering solenoid valve harness connector.

3.

Check resistance between power steering solenoid valve connector terminals.

4.

Check power steering solenoid valve by listening for its operation sound while applying battery voltage to
power steering solenoid valve connector E52 terminals 1 (positive) and 2 (negative).

Is the inspection result normal?

 YES

>> INSPECTION END

 NO

>> Replace gear-sub assembly. Refer to 

ST-44, "Exploded View"

 (With heated steering wheel), 

ST-

85, "Exploded View"

 (Without heated steering wheel).

Power steering solenoid valve

Resistance (Approx.)

Terminal

1 2

4 

– 

6 

Ω

Revision: 2013 February

2012 MURANO

ENGINE SPEED SIGNAL CIRCUIT

STC-9

< DTC/CIRCUIT DIAGNOSIS >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

ENGINE SPEED SIGNAL CIRCUIT

Description

INFOID:0000000007540098

ECM sends engine speed signal to power steering control unit.

Diagnosis Procedure

INFOID:0000000007540099

1.

PERFORM ECM SELF-DIAGNOSIS

With CONSULT

1.

Turn the ignition switch ON.

CAUTION:

Never start the engine

2.

Perform “ENGINE” self-diagnosis. Refer to 

EC-129, "CONSULT Function"

.

Is any DTC detected?

YES

>> Check the DTC.

NO

>> GO TO 2.

2.

CHECK HARNESS BETWEEN ECM AND POWER STEERING CONTROL UNIT

1.

Turn the ignition switch OFF.

2.

Disconnect ECM harness connectors.

3.

Disconnect power steering control unit harness connector.

4.

Check continuity between ECM harness connector and power steering control unit harness connector.

5.

Check continuity between power steering control unit harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace damaged parts.

3.

CHECK ENGINE SPEED SIGNAL (1)

1.

Connect ECM harness connectors.

2.

Check signal between ECM harness connector and ground with oscilloscope.

ECM

Power steering control unit

Continuity

Connector

Terminal

Connector

Terminal

E16

94

M61

10

Existed

Power steering control unit

—

Continuity

Connector

Terminal

M61

10

Ground

Not existed

Revision: 2013 February

2012 MURANO

STC-10

< DTC/CIRCUIT DIAGNOSIS >

ENGINE SPEED SIGNAL CIRCUIT

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Replace ECM. Refer to 

EC-17, "ADDITIONAL SERVICE WHEN REPLACING CONTROL UNIT :

Description"

.

4.

CHECK ENGINE SPEED SIGNAL (2)

1.

Turn the ignition switch OFF.

2.

Connect power steering control unit harness connector.

3.

Check signal between power steering control unit harness connector and ground with oscilloscope.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Replace power steering control unit. Refer to 

STC-20, "Removal and Installation"

.

5.

CHECK TERMINALS AND HARNESS CONNECTORS

• Check power steering control unit pin terminals for damage or loose connection with harness connector.
• Check ECM pin terminals for damage or loose connection with harness connector.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Repair or replace damaged parts.

ECM

Ground

Condition

Voltage

(Approx.)

Connector

Terminal

E16

94

Ground

Engine is running
• Warm-up condition
• Idle speed

Engine is running
• Warm-up condition
• Engine speed: Approx. 2,000 rpm

JMBIA0076GB

JMBIA0077GB

Power steering control unit

—

Condition

Voltage

(Approx.)

Connector

Terminal

M61

10

Ground

Engine is running
• Warm-up condition
• Idle speed

Engine is running
• Warm-up condition
• Engine speed: Approx. 2,000 rpm

JMBIA0076GB

JMBIA0077GB

Revision: 2013 February

2012 MURANO

VEHICLE SPEED SIGNAL CIRCUIT

STC-11

< DTC/CIRCUIT DIAGNOSIS >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

VEHICLE SPEED SIGNAL CIRCUIT

Description

INFOID:0000000007540100

Combination meter sends vehicle speed signal to power steering control unit.

Diagnosis Procedure

INFOID:0000000007540101

1.

PERFORM COMBINATION METER SELF-DIAGNOSIS

With CONSULT

1.

Turn the ignition switch ON.

CAUTION:

Never start the engine

2.

Perform “METER/M&A” self-diagnosis. Refer to 

MWI-35, "CONSULT Function (METER/M&A)"

.

Is any DTC detected?

YES

>> Check the DTC.

NO

>> GO TO 2.

2.

CHECK HARNESS BETWEEN COMBINATION METER AND POWER STEERING CONTROL UNIT

1.

Turn the ignition switch OFF.

2.

Disconnect combination meter harness connector.

3.

Disconnect power steering control unit harness connector.

4.

Check continuity between combination meter harness connector and power steering control unit harness
connector.

5.

Check continuity between power steering control unit harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace damaged parts.

3.

CHECK VEHICLE SPEED SIGNAL (1)

1.

Turn the ignition switch OFF.

2.

Connect combination meter harness connector.

3.

Check combination meter input/output standard values. Refer to 

MWI-58, "Reference Value"

.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Replace combination meter Refer to 

MWI-94, "Exploded View"

.

4.

CHECK VEHICLE SPEED SIGNAL (2)

1.

Turn the ignition switch OFF.

2.

Connect power steering control unit harness connector.

3.

Check signal between power steering control unit harness connector and ground with oscilloscope.

Combination meter

Power steering control unit

Continuity

Connector

Terminal

Connector

Terminal

M34

30

M61

8

Existed

Power steering control unit

—

Continuity

Connector

Terminal

M61

8

Ground

Not existed

Revision: 2013 February

2012 MURANO

STC-12

< DTC/CIRCUIT DIAGNOSIS >

VEHICLE SPEED SIGNAL CIRCUIT

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Replace power steering control unit. Refer to 

STC-20, "Removal and Installation"

.

5.

CHECK TERMINALS AND HARNESS CONNECTORS

• Check power steering control unit pin terminals for damage or loose connection with harness connector.
• Check combination meter pin terminals for damage or loose connection with harness connector.
Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Repair or replace damaged parts.

Power steering control unit

—

Condition

Voltage

(Approx.)

Connector

Terminal

M61

 8

Ground

Vehicle speed: 40 km/h (25 MPH)

CAUTION:

Check air pressure of tire under 
standard condition.

NOTE:
The maximum voltage varies de-
pending on the specification (desti-
nation unit).

JSNIA0015GB

Revision: 2013 February

2012 MURANO

POWER STEERING CONTROL UNIT

STC-13

< ECU DIAGNOSIS INFORMATION >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

ECU DIAGNOSIS INFORMATION

POWER STEERING CONTROL UNIT

Reference Value

INFOID:0000000007540102

TERMINAL LAYOUT

PHYSICAL VALUES

JSGIA0023ZZ

Terminal No.

(Wire color)

Description

Condition

Value (Approx.)

+

-

Signal name

Input/

Output

1

(Y)

Ground

Power steering solenoid 
valve voltage

Output

Vehicle speed: 0 km/h (0 MPH)
(Engine is running)

4.4 – 6.6 V

Vehicle speed: 100 km/h (62 MPH)

2.4 – 3.6 V

3

(G)

Ground

Ignition switch power 
supply

Input

Ignition switch: ON

Battery voltage

Ignition switch: OFF

0 V

5

(LG)

Ground

Power steering solenoid 
valve ground

—

Always

0  V

6

(B)

Ground

Ground

—

Always

0 V

8

(P)

Ground

Vehicle speed signal

Input

Vehicle speed: 40 km/h (25 MPH)

CAUTION:

Check air pressure of tire under 
standard condition.

NOTE:
The maximum voltage varies de-
pending on the specification 
(destination unit).

JSNIA0015GB

Revision: 2013 February

2012 MURANO

STC-14

< ECU DIAGNOSIS INFORMATION >

POWER STEERING CONTROL UNIT

CAUTION:

When using circuit tester or oscilloscope to measure voltage for inspection, be sure not to forcibly extend any connector ter-
minals.

10

(V)

Ground

Engine speed signal

Input

Engine is running
• Warm-up condition
• Idle speed

Engine is running
• Warm-up condition
• Engine speed: Approx. 2,000 rpm

Terminal No.

(Wire color)

Description

Condition

Value (Approx.)

+

-

Signal name

Input/

Output

JMBIA0076GB

JMBIA0077GB

Revision: 2013 February

2012 MURANO

POWER STEERING CONTROL UNIT

STC-15

< ECU DIAGNOSIS INFORMATION >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

Wiring Diagram - ELECTRONICALLY CONTROLLED POWER STEERING SYSTEM -

INFOID:0000000007540103

For connector terminal arrangements, harness layouts, and alphabets in a 

 (option abbreviation; if not

described in wiring diagram), refer to 

GI-12, "Connector Information"

.

Fail-Safe

INFOID:0000000007540104

EPS system

JCGWM0180GB

Revision: 2013 February

2012 MURANO

STC-16

< ECU DIAGNOSIS INFORMATION >

POWER STEERING CONTROL UNIT

• EPS system enters the fail-safe mode (that allows the steering

force to be controlled without impairing the drivability) if any of the
input/output values to/from EPS system (power steering control
unit) deviate from the standard range.
NOTE:
The system enters the fail-safe mode if the engine speed remains
at 1,500 rpm or more for over 10 seconds while the vehicle is
stopped. This is normal.

• The fail-safe function is canceled when a vehicle speed signal of 2

km/h (1.2 MPH) or more is inputted or the ignition switch is turned
OFF

→

ON. EPS system restores the normal operation at that time.

JSGIA0368GB

Mode

Warn-

ing lamp

DTC

Detection point (malfunction part)

Error area and root cause

Fail-safe 

function

—

—

Vehicle speed signal input

• Engine speed is 1,500 rpm or more and there is no vehicle 

speed signal input for over 10 seconds during vehicle travel.

• Vehicle speed signal has abruptly dropped from 30 km/h (19 

MPH) or more to 2 km/h (1.2 MPH) or less within 1.4 sec-
onds.

Revision: 2013 February

2012 MURANO

UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIATION)

STC-17

< SYMPTOM DIAGNOSIS >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

SYMPTOM DIAGNOSIS

UNBALANCE STEERING WHEEL TURNING FORCE (TORQUE VARIA-
TION)

Description

INFOID:0000000007540105

• Hard steering when fully turning the steering wheel.
• Light steering when driving at a high speed.

Diagnosis Procedure

INFOID:0000000007540106

1.

CHECK SYSTEM FOR POWER SUPPLY AND GROUND

Perform trouble diagnosis for power supply and ground. Refer to 

STC-6, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace damaged parts.

2.

CHECK SYSTEM FOR VEHICLE SPEED SIGNAL

Perform trouble diagnosis for vehicle speed signal. Refer to 

STC-11, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace damaged parts.

3.

CHECK SYSTEM FOR ENGINE SPEED SIGNAL

Perform trouble diagnosis for engine speed signal. Refer to 

STC-9, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace damaged parts.

4.

CHECK SYSTEM FOR POWER STEERING SOLENOID VALVE

Perform trouble diagnosis for power steering solenoid valve. Refer to 

STC-7, "Diagnosis Procedure"

.

Is the inspection result normal?

YES

>> Perform the symptom diagnosis for the steering system. Refer to 

ST-27, "NVH Troubleshooting

Chart"

 (With heated steering wheel), 

ST-73, "NVH Troubleshooting Chart"

 (Without heated steer-

ing wheel).

NO

>> Repair or replace damaged parts.

Revision: 2013 February

2012 MURANO

STC-18

< PRECAUTION >

PRECAUTIONS

PRECAUTION

PRECAUTIONS

FOR USA AND CANADA

FOR USA AND CANADA : Precaution for Supplemental Restraint System (SRS) "AIR 
BAG" and "SEAT BELT PRE-TENSIONER"

INFOID:0000000007540107

The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the “SRS AIR BAG” and “SEAT BELT” of this
Service Manual.

WARNING:

Always observe the following items for preventing accidental activation.
• To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death in

the event of a collision that would result in air bag inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.

• Improper maintenance, including incorrect removal and installation of the SRS, can lead to personal

injury caused by unintentional activation of the system. For removal of Spiral Cable and Air Bag
Module, see “SRS AIR BAG”.

• Never use electrical test equipment on any circuit related to the SRS unless instructed to in this Ser-

vice Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or harness
connectors.

PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS

WARNING:

Always observe the following items for preventing accidental activation.
• When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the

ignition ON or engine running, never use air or electric power tools or strike near the sensor(s) with
a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly causing
serious injury.

• When using air or electric power tools or hammers, always switch the ignition OFF, disconnect the

battery, and wait at least 3 minutes before performing any service.

FOR MEXICO

FOR MEXICO : Precaution for Supplemental Restraint System (SRS) "AIR BAG" and 
"SEAT BELT PRE-TENSIONER"

INFOID:0000000007814143

The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. Information necessary to service the system safely is included in the “SRS AIR BAG” and
“SEAT BELT” of this Service Manual.

WARNING:

Always observe the following items for preventing accidental activation.
• To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death in

the event of a collision that would result in air bag inflation, all maintenance must be performed by
an authorized NISSAN/INFINITI dealer.

• Improper maintenance, including incorrect removal and installation of the SRS, can lead to personal

injury caused by unintentional activation of the system. For removal of Spiral Cable and Air Bag
Module, see “SRS AIR BAG”.

• Never use electrical test equipment on any circuit related to the SRS unless instructed to in this Ser-

vice Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or harness
connectors.

PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS

WARNING:

Revision: 2013 February

2012 MURANO

PRECAUTIONS

STC-19

< PRECAUTION >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

Always observe the following items for preventing accidental activation.
• When working near the Air Bag Diagnosis Sensor Unit or other Air Bag System sensors with the

ignition ON or engine running, never use air or electric power tools or strike near the sensor(s) with
a hammer. Heavy vibration could activate the sensor(s) and deploy the air bag(s), possibly causing
serious injury.

• When using air or electric power tools or hammers, always switch the ignition OFF, disconnect the

battery, and wait at least 3 minutes before performing any service.

Revision: 2013 February

2012 MURANO