Nissan Altima HL32 Hybrid. Manual - part 1057

EPS SYSTEM

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FUNCTION DIAGNOSIS

EPS SYSTEM

System Diagram

INFOID:0000000004212822

CONTROL DIAGRAM

System Description

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DESCRIPTION

The EPS system generates assist torque to assist steering effort through the operation of the motor installed

on the steering gear assembly.

the direction and amount of power assistance are determined by signals from the torque sensor and controlled

in accordance with vehicle speed. As a result, steering effort is controlled to be light during low speed driving

and moderately high during high speed driving.

JSGIA0158GB

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< FUNCTION DIAGNOSIS >

EPS SYSTEM

Component Parts Location

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1.

EPS warning lamp

2.

EPS motor angle sensor (in steering 
gear assembly)

3.

EPS motor (in steering gear assem-
bly)

4.

Torque sensor (in steering gear as-
sembly)

5.

EPS control unit

6.

EPS DC/DC converter

7.

Steering angle sensor

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EPS SYSTEM

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Component Description

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Component parts

Function

EPS control unit
(Electric power steering control unit)

• Outputs optimum assist torque signal to EPS motor.
• Reduces output signals to EPS motor and protects EPS motor and EPS control unit 

when using power steering continuously and excessively.

• As a fail-safe function, turned off output signal to EPS motor and then enters a manual 

steering state, if malfunction is detected in EPS system.

EPS motor

Products assist torque by control signal from EPS control unit.

Torque sensor

Detects steering wheel turning force and outputs sensor signal to EPS control unit.

EPS motor angle sensor

Detects EPS motor rotation angle and outputs sensor signal to EPS control unit.

EPS DC/DC converter

Is controlled by EPS control unit. Steps down HV battery-supplied voltage to 42V to sup-
ply power to EPS motor through motor driving circuit in EPS control unit.

EPS warning lamp

Illuminates if malfunction is detected in electrical system of EPS system.

Brake ECU

Transmits the following signals via CAN communication to EPS control unit.
• Vehicle speed signal

Steering angle sensor

Transmits the following signals via CAN communication to EPS control unit.
• Steering angle signal

HV ECU
(Hybrid Vehicle Control ECU)

• Transmits the following signals via CAN communication to EPS control unit.
- Power steering assist permission signal
- Power steering assist stop request signal
- READY status signal
• Receives the following signals via CAN communication from EPS control unit
- Power steering assist signal

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< FUNCTION DIAGNOSIS >

DIAGNOSIS SYSTEM (EPS CONTROL UNIT)

DIAGNOSIS SYSTEM (EPS CONTROL UNIT)

CONSULT-III Function (EPS)

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FUNCTION

CONSULT-III can display each diagnostic item using the diagnostic test modes shown following.

WORK SUPPORT MODE

Work Item

SELF-DIAG RESULT MODE

Display Item List

Diagnostic test mode

Function

Work support

• This mode enables a technician to adjust some devices faster and more accurately by following 

the indications on CONSULT-III.

Self-diagnostic results

• Self-diagnostic results can be read and erased quickly.

Data monitor

• Input/Output data in the EPS control unit can be read.

ECU part number

• EPS control unit part number can be read.

Work item

Condition

Usage

SENSOR CALIBRATION

• Ignition voltage is more than 10 V
• The steering wheel to the straight-

ahead position

• No DTC detected

Use to EPS motor angle sensor initialization and torque sensor 
calibration when replacing EPS control unit, replacing steering 
gear assembly and/or unbalanced steering wheel turning force.

DTC

Item

(CONSULT-III screen term)

DTC detecting condition

Possible cause

C1601

BATTERY VOLT

When the power supply malfunction supplied to EPS 
control unit is detected.

• Power supply
• Harness or connector
• EPS control unit

C1604

TORQUE SENSOR

When the torque sensor malfunction built in steering 
gear assembly is detected.

• Torque sensor calibration in-

complete

• Harness or connector
• Torque sensor
• EPS control unit

C1606

EPS MOTOR

When the motor driver malfunction in EPS control 
unit or EPS motor malfunction is detected.

• EPS motor angle sensor ini-

tialization incomplete

• EPS motor angle sensor
• Harness or connector
• EPS motor
• EPS control unit

C1607

EEPROM

When the memory (EEPROM) system malfunction is 
detected in EPS control unit.

• EPS control unit

C1608

CONTROL UNIT

When the internal malfunction is detected in EPS 
control unit.

• EPS control unit

C1609

VHCL SPEED SIGNAL

Malfunction is detected in vehicle speed signal that is 
output from brake ECU through CAN communica-
tion.
(Improper signal inputs while driving.)

• Wheel sensor
• Brake  ECU
• Harness or connector

(CAN communication line)

• EPS control unit

C1613

TQ SE CLB NOT PFRM

Torque sensor calibration is not performed.

• Torque sensor calibration 

not performed

C16A0

HV ECU

Malfunction has been detected from HV ECU.

• HV ECU