Nissan Sentra. Manual - part 826

DIAGNOSIS SYSTEM (EPS CONTROL UNIT)

STC-11

< SYSTEM DESCRIPTION >

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*1: Almost in accordance with the value of “MOTOR SIG”. It is not a malfunction though these values are not

accorded when steering quickly.

*2: Normally displays 100%. In case of an excessive stationary steering, the assist curvature gradually falls.

However, it returns to 100% when left standing.

*3: It is not a malfunction, though it might not be corresponding just after ignition switch in turned ON.

STC-12

< ECU DIAGNOSIS INFORMATION >

EPS CONTROL UNIT

ECU DIAGNOSIS INFORMATION

EPS CONTROL UNIT

Reference Value

INFOID:0000000009757429

VALUES ON THE DIAGNOSIS TOOL

The following table includes information (items) inapplicable to this vehicle. For information (items) applicable

to this vehicle, refer to CONSULT display items.

CAUTION:

The output signal indicates the EPS control unit calculation data. The normal values will be displayed

even in the event that the output circuit (harness) is open.

*1: Almost in accordance with the value of “MOTOR SIG”. It is not a malfunction though these values are not

accorded when steering quickly.

*2: A fixed value is indicated regardless of steering turning.

*3: Normally displays 100%. In case of an excessive stationary steering, the assist curvature gradually falls.

However, it returns to 100% when left standing.

*4: It is not a malfunction, though it might not be corresponding just after ignition switch in turned ON.

Monitor item 

Data monitor

Condition

Display value

BATTERY VOLT

Ignition switch: ON

Battery voltage

TORQUE SENSOR

Engine running

Steering wheel: Not steering (There is 
no steering force)

Approx. 0 Nm

Steering wheel: Right turn

Positive value (Nm)

Steering wheel: Left turn

Negative value (Nm)

MOTOR CURRENT

Engine running

Steering wheel: Not steering (There is 
no steering force)

Approx. 0 A

Steering wheel: Right or left turn

Displays consumption current of 
EPS motor (A)

*1

MOTOR SIG

Engine running

Steering wheel: Not steering (There is 
no steering force)

Approx. 0 A

Steering wheel: Right turn

Positive value (A)

Steering wheel: Left turn

Negative value (A)

ASSIST TORQUE

Engine running

Approx. 0 Nm

*2

C/U TEMP

Ignition switch ON or engine running

Displays temperature of inside of 
EPS control unit [

°C (°F)]

ASSIST LEVEL

Engine running

100 %

*3

VEHICLE SPEED

Vehicle stopped

0 km/h (0 mph)

While driving

Approximately equal to the indication 
on speedometer

*4

(inside of 

±10%)

WARNING LAMP

EPS warning lamp: ON

On

EPS warning lamp: OFF

Off

ENGINE STATUS

Engine not running

Stop

Engine running

Run

EPS CONTROL UNIT

STC-13

< ECU DIAGNOSIS INFORMATION >

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TERMINAL LAYOUT

PHYSICAL VALUES

Fail-Safe

INFOID:0000000009757430

• If any malfunction occurs in the system and control unit detects the malfunction, EPS warning lamp on com-

bination meter turns ON to indicate system malfunction.

• When EPS warning lamp is ON, the system enters into a manual steering state. (Control turning force steer-

ing wheel becomes heavy.)

• Under abnormal vehicle speed signal conditions, vehicle speed is judged as constant.

Protection Function

INFOID:0000000009757431

EPS control unit decreases the output signal to EPS motor while extremely using the power steering function

(e.g., full steering) consecutively for protecting EPS motor and EPS control unit (Overload protection control).

While activating overload protection control, the assist torque gradually decreases, and the steering wheel

ALGIA0156ZZ

Terminal No.

(Wire Color)

Description

Condition

Value

(Approx.)

+

−

Signal name

Input/Output

1

(P)

—

CAN-L

Input/Output

—

—

2

(L)

—

CAN-H

Input/Output

—

—

4

(BR)

Ground

Ignition power supply

Input

Ignition switch: ON

Battery voltage

Ignition switch: OFF

0 V

9

(R)

Ground

Battery power supply

Input

Always

Battery voltage

10

(B)

Ground

Ground

—

Always

0 V

15

(R)

Ground

Torque sensor ground

—

Always

0 V

16

(Y)

Ground

Torque sensor main

Input

Ignition switch: ON

Steering wheel: Not 
steering (There is no 
steering force)

2.5 V

Engine running

Steering wheel: steer-
ing

1.6 V – 3.4 V

(The value is changed 

according to steering 

left or right)

17

(B)

Ground

Torque sensor sub

Input

Ignition switch: ON

Steering wheel: Not 
steering (There is no 
steering force)

2.5 V

Engine running

Steering wheel: steer-
ing

1.6 V – 3.4 V

(The value is changed 

according to steering 

left or right)

18

(W)

Ground

Torque sensor power 
supply

Output

Ignition switch: ON

5 V

STC-14

< ECU DIAGNOSIS INFORMATION >

EPS CONTROL UNIT

turning force becomes heavy. The normal assist torque is recovered if the steering wheel is not turned for a

while.

DTC Inspection Priority Chart

INFOID:0000000009757432

When multiple DTCs are detected simultaneously, check one by one depending on the following priority list. 

DTC Index

INFOID:0000000009757433

*: Even if DTC is detected, EPS warning lamp does not turn ON when assist torque is generated.

Priority

Priority order item (DTC)

1

U1000 CAN COMM CIRCUIT

2

C1609 CAN VHCL SPEED

3

C1601 BATTERY VOLT

4

Other than the above

DTC

Items

EPS warning lamp

Reference

C1601

BATTERY VOLT

ON

STC-22, "DTC Logic"

C1604

TORQUE SENSOR

ON

STC-25, "DTC Logic"

C1606

EPS MOTOR

ON

STC-27, "DTC Logic"

C1607

EEPROM

OFF

STC-28, "DTC Logic"

C1608

CONTROL UNIT

ON / OFF

*

STC-28, "DTC Logic"

C1609

CAN VHCL SPEED

ON

STC-29, "DTC Logic"

U1000

CAN COMM CIRCUIT

ON

STC-30, "DTC Logic"