Nissan Ariya: System Description

• Component Parts
• System. Eps System
• Diagnosis System (eps Control Unit). Consult Function

System. Eps System

System Description

SYSTEM DIAGRAM

DESCRIPTION

• EPS system consists mainly of power steering control module, EPS motor, power steering torque sensor.

  

• EPS system calculates a control signal to transmit to the EPS motor based on information received from each control unit via CAN communication and information received from power steering torque sensor.

• Power steering control module performs an arithmetical operation on data, such as steering wheel turning force (sensor signal) from the power steering torque sensor, Nissan Ariya vehicle speed signal, etc. Then it generates an optimum assist torque signal to the EPS motor according to the driving condition.

• After set the Nissan Ariya vehicle to READY, the EPS system performs control.

• When a malfunction occurs in the system, the fail-safe function stops the EPS system. Refer to Fail- Safe.

• Power steering control module decreases the output signal to EPS motor while extremely using the power steering function (e.g., full steering) consecutively for protecting EPS motor and power steering control module (Overload protection control). Refer to Protection Function.

• The characteristics of steering can be set as follows in information display.

  Mode	Description
  Standard	The setting of the steering system is normal feel.
  Sport	The setting of the steering system is adjusted to moderately increase steering wheel effort for a sporty feel.
  Drive Mode	The setting of the steering system is follow the drive mode selector switches settings.

CONDITIONS FOR POWER STEERING WARNING LAMP ON

• Turn ON when there is a malfunction in EPS system and activates the fail-safe mode to indicate that the assist timing during steering operation shifts or becomes heavier.

• Also turns ON when power switch is ON, for purpose of lamp check. Turns OFF after the set the Nissan Ariya vehicle to READY, if system is normal.

CAUTION:

Even if the power steering warning lamp turns ON, it does not necessarily mean that the power steering control module has failed, and the power steering warning lamp turns ON due to abnormal data reception from another control unit or an abnormality in CAN communication.

Circuit Diagram

Fail-safe

• When a malfunction occurs in the system, it will be in a fail-safe state (EPS system control stop state).

• In the fail-safe state, the control signal to the EPS motor is stopped and become in the manual steering state (steering wheel steering force becomes heavy). And the power steering warning lamp is turned ON to indicate that a malfunction has occurred in the system.

*1: Depends on the calibration status

*2: Depends on the DTC detection status

Protection Function

Power steering control module decreases the output signal to EPS motor while extremely using the power steering function (e.g., full steering) consecutively for protecting EPS motor and power steering control module (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.

Warning / Indicator / Chime List

Name	Design	Layout/Function
Power steering warning lamp		For layout, refer to Design.
		For function, refer to Power steering warning lamp.

Handling Precaution

Check the following item when performing the trouble diagnosis.

• Check any possible causes by interviewing the symptom and it′s condition from the customer if any malfunction, such as power steering warning lamp is turned ON, occurs.

• Check if air pressure and size of tires are proper, the specified part is used for the steering wheel, and control unit is genuine part.

• Check if the connection of steering column assembly and steering gear assembly is proper (there is not looseness of mounting bolts, damage of rods, boots or sealants, and leakage of grease, etc).

• Check if the wheel alignment is adjusted properly.

• Check if there is any damage or modification to suspension or body resulting in increased weight or altered ground clearance.

• Check if installation conditions of each link and suspension are proper.

• Check if the 12V battery voltage is proper.

• Check connection conditions of each connector are proper.

  CAUTION:

  Never disconnect power steering control module harness connector.

• Before connecting or disconnecting the power steering control module harness connector, turn power switch “OFF” and disconnect 12V battery ground cable.

Diagnosis System (eps Control Unit). Consult Function

Diagnosis Description

APPLICATION ITEMS

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

SELF DIAGNOSTIC RESULT

Refer to DTC Index .

When “CRNT” is displayed on self-diagnosis result.

• The system is presently malfunctioning.

When “PAST” is displayed on self-diagnosis result.

• System malfunction in the past is detected, but the system is presently normal.

Freeze frame data (FFD)

The following vehicle status is recorded when DTC is detected and is displayed on CONSULT.

DATA MONITOR

NOTE:

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

ECU IDENTIFICATION

Displays the part number stored in the power steering control module.

WORK SUPPORT

REPLACE ECU

Write the vehicle specification when replacing power steering control module.

Component PartsBasic Inspection