Nissan X-Trail 32. Manual - part 1992

STC-18

< ECU DIAGNOSIS INFORMATION >

EPS CONTROL UNIT

ECU DIAGNOSIS INFORMATION

EPS CONTROL UNIT

Reference Value

INFOID:0000000010688408

VALUES ON THE DIAGNOSIS TOOL

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.
NOTE:
The following table includes information (items) inapplicable to this vehicle. For information (items) applicable
to this vehicle, refer to CONSULT display items.

Monitor item 

Data monitor

Condition

Value/Status

BATTERY VOLT

Ignition switch: ON

10.5 V – 16 V

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

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)

C/U TEMP

Ignition switch ON or engine running

Displays temperature of inside of 
EPS control unit [

°

C (

°

F)]

ASSIST LEVEL

Engine running

100 % 

*2

VEHICLE SPEED

Vehicle stopped

0 km/h (0 mph)

While driving

Approximately equal to the indication 

on speedometer

*3

(inside of 

±

10%)

WARNING LAMP

EPS warning lamp: ON

On

EPS warning lamp: OFF

Off

ENGINE STATUS

Engine not running

Stop

Engine running

Run

ST TORQUE STATUS

Engine running

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

Off

Steering wheel: Right or left turn

On

EPS ASSIST PERMIS

Engine running

Status other than stop/start system

On

In stop/start system operation

Off

EPS CONTROL UNIT

STC-19

< ECU DIAGNOSIS INFORMATION >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

*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.

TERMINAL LAYOUT

PHYSICAL VALUES

STOP/START STATUS

When stop/start system is inactive

INACT

When stop/start system is restarting

AUTO ST

When stop/start system is active

ACT

When stop/start system is interrupted

CANCEL

IPA ON

EPS system operating conditions are not satisfied

Off1

EPS system or around view monitor with park assist is abnormal

Off2

Assist torque is larger than a command value from around view 
monitor with park assist

Off3

Normal condition

On

IPA STATUS 1

Around view monitor with park assist is in operation

On

Around view monitor with park assist is not in operation

Off

STOP/START SYSTEM

When stop/start system is active

On

When stop/start system is prohibited

Off

IPA STATUS 2

Around view monitor with park assist is not in operation

Off

Around view monitor with park assist is in operation (steering 
wheel is not turned)

On1

The following cases
• Around view monitor with park assist in operation
• Steering wheel is turned
• Sonar is not operation

On2

The following cases
• Around view monitor with park assist in operation
• Steering wheel is turned
• Sonar is operation

On3

IPA STATUS 3

Around view monitor with park assist is normal

NORMAL

Around view monitor with park assist is abnormal

MALF

IPA TARGET CURRENT

Around view monitor with park assist is in operation

0 – 70(A)

EPS CONTROL CUR-
RENT

EPS system is in operation

0 – 90 (A)

Monitor item 

Data monitor

Condition

Value/Status

JSGIA1434ZZ

STC-20

< ECU DIAGNOSIS INFORMATION >

EPS CONTROL UNIT

Fail-Safe

INFOID:0000000010688409

• If any malfunction occurs in the system and control unit detects the malfunction, Electric power steering

warning lamp on combination meter turns ON to indicate system malfunction.

• When Electric power steering warning lamp is ON, the system enters into a manual steering state. (Control

turning force steering wheel becomes heavy.)

Protection Function

INFOID:0000000010688410

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
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:0000000010688411

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

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

(SB)

Ground

Ignition power supply

Input

Ignition switch: ON

10.5 V – 16 V

Ignition switch: OFF

Approx. 0 V

9

(R)

Ground

Battery power supply

Input

Always

10.5 V – 16 V

10

(B)

Ground

Ground

—

Always

Approx. 0 V

DTC

Fail-safe condition

C1601

Assist is reduced according to voltage, resulting in manual steering state.

C1604

Manual steering state.

C1606

C1607

C1608

C1609

Constant steering assist level state

U1000

Normal control
NOTE:
If the cause is in a different ECU, the state changes to fixed steering assist force.

U1010

Normal control

U1970

Around view monitor with park assist function stops (controlled by around view monitor).

U1971

Around view monitor with park assist function stops (controlled by sonar).

Priority

Priority order item (DTC)

1

• U1000 CAN COMM CIRCUIT
• U1010 CONTROL UNIT (CAN)

2

• U1970 AROUND VIEW MONITOR SYSTEM
• U1971 SONAR SYSTEM
• C1609 CAN VHCL SPEED

EPS CONTROL UNIT

STC-21

< ECU DIAGNOSIS INFORMATION >

C

D

E

F

H

I

J

K

L

M

A

B

STC

N

O

P

DTC Index

INFOID:0000000010688412

*: Even if DTC is detected, electric power steering warning lamp does not turns ON when assist torque is gen-
erated.

3

C1601 BATTERY VOLT

4

• C1604 TORQUE SENSOR
• C1606 EPS MOTOR
• C1607 EEPROM
• C1608 CONTROL UNIT

Priority

Priority order item (DTC)

DTC

Items

Electric power steering warning lamp

Reference

C1601

BATTERY VOLT

ON

STC-27, "DTC Description"

C1604

TORQUE SENSOR

ON

STC-30, "DTC Description"

C1606

EPS MOTOR

ON

STC-31, "DTC Description"

C1607

EEPROM

OFF

STC-32, "DTC Description"

C1608

CONTROL UNIT

ON / OFF

*

STC-32, "DTC Description"

C1609

CAN VHCL SPEED

OFF

STC-33, "DTC Description"

U1000

CAN COMM CIRCUIT

OFF

STC-34, "DTC Description"

U1010

CONTROL UNIT (CAN)

OFF

STC-35, "DTC Description"

U1970

AROUND VIEW MONITOR

OFF

STC-36, "DTC Description"

U1971

SONAR

OFF

STC-38, "DTC Description"