Mitsubishi Outlander (2013+). Manual - part 69

 

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Mitsubishi Outlander (2013+). Manual - part 69

 

 

ELECTRIC POWER STEERING

ELECTRIC POWER STEERING (EPS)

37-6

GENERAL DESCRIPTION ON SYSTEM

To improve operational reliability, the dual-circuit sys-
tem has been adopted for the torque sensor. If any 
malfunction occurs in the electric power steering sys-
tem, the fail-safe function of the EPS-ECU is acti-
vated, and the output current of the EPS-ECU 
applied to the motor is turned off. At the same time, 
the steering system enters manual mode, and 

informs a driver of the system malfunction by illumi-
nating the warning lamp on the combination meter. 
The warning lamp illuminates when the following 
malfunctions occur: open circuit in the electric power 
steering system wiring harness, poor connection, 
malfunctions in the EPS-ECU, motor, or sensors.

ELECTRICAL PARTS AND FUNCTIONS

ACB05501AB

EPS-ECU

Motor

Torque sensor

Parts name

Description about function

Sensor

Wheel speed sensor (ABS-ECU 
or ASC-ECU)

The vehicle speed signal is sent from the ABS-ECU or 
ASC-ECU to the EPS-ECU via the engine-ECU.

Torque sensor

Detects a steering force, converts it into the voltage signal, 
and then sends the signal to the EPS-ECU.

Actuator

Motor

Generates assist torque by the steering operation to the 
column shaft using the signals sent from the EPS-ECU.

Electric power steering warning 
lamp (in combination meter)

Warns a driver of the system malfunction using the signal 
sent from the EPS-ECU.

EPS-ECU

Control the actuator (motor) based on the signal sent from 
sensor.

Controls the self-diagnostic function and fail-safe function.

Controls diagnostic function (Compatible with M.U.T.-III).

ELECTRIC POWER STEERING

ELECTRIC POWER STEERING (EPS)

37-7

SYSTEM CONFIGURATION

MOTOR

M2370001100122

The EPS motor receives the control current from the 
EPS-ECU, and rotates in accordance with steering 
operation. The rotational force generated by the EPS 
motor is transmitted via the worm shaft and the 
reduction gear to the column shaft.

ACB05502

EPS-ECU Power supply

Ignition switch

Torque sensor signal (main)

Earth

Torque sensor signal (sub)

Motor current

EPS-ECU

Torque sensor

Motor

Engine-ECU

ETACS-ECU

AWC-ECU

Output current value

Diagnosis 
connector

Combination 
meter

Engine speed

EPS warning lamp

Vehicle speed

Odometer 

(distance information)

Diagnosis code output

Additional Torque

Diagnosis code allowed 
to be stored

Steering column
shaft assembly

AB

NOTE:                       line indicates the CAN communication.

ACB05503 AB

A

A

Worm shaft

Reduction gear

Sectional view A - A

Motor

ELECTRIC POWER STEERING

ELECTRIC POWER STEERING (EPS)

37-8

TORQUE SENSOR

M2370001600020

The torque sensor is mounted on the column shaft, 
and detects the steering force. When the steering 
wheel is turned, the phase relationship between the 
input shaft and the lower shaft will be changed due to 
distortion of the torsion bar. The torque sensor will 
detect the distortion angle and send two voltage sig-
nals (main and sub) to the EPS-ECU in accordance 
with it.

ELECTRIC POWER STEERING-ECU 
(EPS-ECU)

M2370000800195

The EPS-ECU includes an input interface circuit, a 
microprocessor, an output drive circuit, a power relay 
and a motor line relay. It also integrates a self-diag-
nostic function, and illuminates the warning lamp on 
the combination meter when a trouble occurs. At the 
same time, it sends diagnosis code(s) to the diagno-
sis connector.

CAN communication

The EPS-ECU communicates with the other ECUs 
and other units through CAN communication to con-
trol the steering system.

NOTE: Indicates items which send and receive data 
through CAN communication.

ACB05508

AB

Torque sensor

Lower shaft

Torsion bar

Torque sensor

Input shaft

Output voltage (V)

Torque sensor characteristic chart

Neutral

Sub

Main

5

2.5

Input signals

Sent to

Engine-ECU

AWC-ECU

Combination 
meter (via the 
ETACS-ECU)

ETACS-ECU

Engine speed

Vehicle speed

Additional torque

Distance information (diagnosis 
additional information)

Vehicle information (diagnosis 
control)

ELECTRIC POWER STEERING

ELECTRIC POWER STEERING (EPS)

37-9

NOTE: Indicates items which send and receive data 
through CAN communication.

Fail-safe function

If the EPS-ECU detects any malfunction, it illumi-
nates the EPS warning lamp, deactivates the EPS 
functions, and then switches the steering system into 
manual mode.

DIAGNOSIS FUNCTION

The EPS-ECU has the following functions to make 
system checks easier.

• Diagnosis code set

• Service data output

All the above items can be diagnosed using MUT-III.

Diagnosis code set

There are 29 diagnostic items. Since all the diagnos-
tic results are recorded in volatile memory (EEP-
ROM*), they are stored in the memory even though 
the battery terminals are disconnected.

NOTE: 

.

*EEPROM (Electrical Erasable & Programmable 
ROM): Special type of memory that can be pro-
grammed or erased electrically.

For diagnosis items, refer to Workshop Manual.

Service data output

Using M.U.T.-III, the input data sent from the sensors 
and motors can be read.

NOTE: For service data items, refer to Workshop 
Manual.

OPERATION

M2370000700217

IGNITION SWITCH ON

Ignition supply voltage is applied to the EPS-ECU, 
and the ECU enters standby mode.

1. When the engine is started, the engine speed sig-

nal sent from the engine-ECU is input to the 
EPS-ECU.

2. After starting the engine, the EPS-ECU judges 

the engine status "ENGINE SPEED ON" when 
the engine speed reaches 500 r/min, then the 
power assist function is ready.

Output signal name

Received by

Engine-ECU

Combination meter 
(via the ETACS-ECU)

Diagnosis connector

Motor current signal

EPS warning lamp illumination 
request signal

Diagnosis code signal

Service data output signal

AC611649

AJ

Electric power 
steering-ECU

Engine-ECU

OFF

OFF

Motor

Motor current signal

Maximum limit value (82Arms)

Engine speed

Engine speed

ON

500 r/min

min 0.6 second

0.8 second

Motor output

Determination of motor 
control start

Temporary increase of motor 
assist limit value

 

 

 

 

 

 

 

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