Nissan Maxima. Manual - part 1127

STC-14

< DTC/CIRCUIT DIAGNOSIS >

VEHICLE SPEED SIGNAL CIRCUIT

2. Turn ignition switch ON.

3. Check voltage between combination meter connector M24 ter-

minal 30 and ground.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair harness or connectors.

4.

CHECK VEHICLE SPEED SIGNAL (COMBINATION METER SIDE)

1. Turn the ignition switch OFF.

2. Connect combination meter connector.

3. Check combination meter input/output standard values. Refer to 

MWI-47, "Reference Value"

.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Replace combination meter. Refer to 

MWI-122, "Removal and Installation"

.

5.

CHECK VEHICLE SPEED SIGNAL (POWER STEERING CONTROL UNIT SIDE)

1. Turn the ignition switch OFF.

2. Connect power steering control unit connector.

3. Start the engine.

4. Check signal between power steering control unit connector

M59 terminal 8 and ground with oscilloscope.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Replace power steering control unit. Refer to 

STC-22, "Removal and Installation"

.

6.

CHECK TERMINALS AND HARNESS CONNECTORS

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

2. 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.

Combination meter

Ground

Voltage (Approx.)

Connector

Terminal

M24

30

—

0V

AWGIA0098ZZ

Power steering control unit

Value (Approx.)

Connector

Terminal

Condition

M59

 8 - Ground

Vehicle speed:
40 km/h (25 
MPH)

CAUTION:

Check air 
pressure of 
tire under 
standard con-
dition.

AWGIA0121ZZ

ELF1080D

POWER STEERING CONTROL UNIT

STC-15

< ECU DIAGNOSIS INFORMATION >

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ECU DIAGNOSIS INFORMATION

POWER STEERING CONTROL UNIT

Reference Value

INFOID:0000000009466561

TERMINAL LAYOUT

PHYSICAL VALUES

CAUTION:

JSGIA0023ZZ

Terminal No.

Wire 

color

Description

Condition

Value (Approx.)

+

-

Signal name

Input/

Output

1

Ground

R/Y

Power steering so-
lenoid 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)

2.5 - 3.7 V

3

Ground

G

Ignition power sup-
ply

Input

Ignition switch: ON

Battery voltage

Ignition switch: OFF

0 V

5

Ground

LG/W

Power steering so-
lenoid valve ground

—

Always

0  V

6

Ground

B

Ground

—

Always

0 V

8

Ground

L/B

Vehicle speed sig-
nal

Input

Vehicle speed: 40 km/h (25 MPH)

CAUTION:

Check air pressure of tire under 
standard condition.

10

Ground

V/W

Engine speed sig-
nal

Input

Engine speed: At idle
(Warm-up condition)

Engine speed: Approx. 2,000 RPM
(Warm-up condition)

ELF1080D

JSGIA0143ZZ

PBIA3655J

STC-16

< ECU DIAGNOSIS INFORMATION >

POWER STEERING CONTROL UNIT

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

Fail Safe

INFOID:0000000009466562

EPS system

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

force to be controlled without impairing the drive ability) if any of

the input/output signals to/from EPS system (power steering con-

trol unit) deviate from the standard.

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 cancelled when a vehicle speed signal of 2

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

OFF

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

ABGIA0091GB

Function

Warn-

ing lamp

DTC No.

Detection point (malfunction part)

Malfunction part and cause

Fail-safe 

function

—

—

Vehicle speed signal

• 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.

ELECTRONICALLY CONTROLLED POWER STEERING SYSTEM

STC-17

< WIRING DIAGRAM >

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WIRING DIAGRAM

ELECTRONICALLY CONTROLLED POWER STEERING SYSTEM 

Wiring Diagram

INFOID:0000000009466563

ABGWA0002GB