Nissan Pathfinder: Steering Control System - System Description

Nissan Pathfinder (R53) 2022-2025 Service Manual / Steering :: Steering Control System / System Description

Component Parts. Electronically Controlled Power Steering System
Diagnosis System (eps Control Unit)

Component Parts. Electronically Controlled Power Steering System Nissan Pathfinder R53

Component Parts Location

	Steering gear assembly (view with steering gear assembly removed)
: Nissan Pathfinder Vehicle front

No.	Component		Function
1.	ABS (Anti-lock Braking System) actuator and electric unit (control unit)		Transmits the Nissan Pathfinder vehicle speed signal (ABS) to EPS control unit via CAN communication. Refer to Component Parts Location for detailed component location.
2.	ECM (Engine Control Module)		Transmits the engine status signal to EPS control unit via CAN communication. Receives the battery supply current signal from EPS control unit via CAN communication. Refer to Component Parts Location for detailed component location.
3.	Combination meter (Power steering warning lamp)		Transmits the Nissan Pathfinder vehicle speed signal (Meter) to EPS control unit via CAN communication. Turns ON the power steering warning lamp according to the signal from the EPS control unit via CAN communication. For power steering warning lamp, refer to Warning Lamp/Indicator Lamp. Refer to Component Parts Location (7 inch information display meter) or Component Parts Location (Full TFT meter) for detailed component location.
4.	Steering angle sensor		Transmits the steering angle sensor signal to EPS control unit via CAN communication. Refer to Component Parts Location for detailed component location.
5.	Steering gear assembly	Torque sensor	Refer to Steering Gear Assembly.
6.		EPS (Electric Power Steering) control unit
7.		EPS motor

Steering Gear Assembly

The steering gear assembly is primarily composed of torque sensor (1), EPS control unit (2) and EPS motor (3).

EPS CONTROL UNIT

By receiving steering angle sensor signal ,vehicle speed signal and torque sensor signal, the EPS control unit calculates the current of motor drive according to the driving conditions. The EPS control unit controls the EPS motor.

TORQUE SENSOR

Torque sensor detects the steering torque, and transmit the signal to EPS control unit.

EPS MOTOR

The EPS motor provides the assist torque by the signal from EPS control unit.

Diagnosis System (eps Control Unit) Nissan Pathfinder R53

CONSULT Function

APPLICATION ITEMS

CONSULT can display each diagnostic item using the diagnostic test modes shown as per the following:

Diagnostic test mode	Function
Self Diagnostic Result	Self diagnostic results and freeze frame data can be read and erased quickly*
Data Monitor	Input/Output data in the EPS control unit can be read.
ECU Identification	The part number stored in the control unit can be read.

^*: The following diagnosis information is erased by erasing:

DTC
Freeze frame data (FFD)

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:

Freeze Frame Data Item	Unit	Description
ODO/TRIP METER	mi or km	Display the odometer value from combination meter via CAN communication.
BATTERY VOLT	V	Displays the power supply voltage for EPS control unit.
IGN SW	OFF/ON	Display the status of ignition switch.
ENGINE STATUS	STOP/RUN/CRANK	Displays the engine status based on the engine status signal transmitted via CAN communications.
Nissan Pathfinder Vehicle SPEED	mph or km/h	Display the Nissan Pathfinder vehicle speed from vehicle speed signal via CAN communication.
STEERING ANGLE SIGNAL	deg	Displays the steering angle based on steering angle signal transmitted via CAN communications.
STEERING TORQUE	Nm	Displays steering torque detected by torque sensor.
MOTOR CURRENT	A	Display the current value consumed by EPS motor.
C/U TEMP	°C	Displays the temperature of the EPS control unit.

DATA MONITOR

NOTE:

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

Monitor item	Unit	Remarks
BATTERY VOLT	V	Displays the power supply voltage for EPS control unit.
STEERING TORQUE	Nm	Displays steering torque detected by torque sensor.
STEERING ANGLE SIGNAL	deg	Displays the steering angle based on steering angle signal transmitted via CAN communications.
MOTOR CURRENT	A	Display the current value consumed by EPS motor.
MOTOR TORQUE COMMAND	A	Displays the target motor current value.
C/U TEMP	°C	Displays the temperature of the EPS control unit.
ASSIST LEVEL	%	Displays the current percentage of the allowable assist ratio EPS motor.
Nissan Pathfinder Vehicle SPEED	mph or km/h	Display the vehicle speed from Nissan Pathfinder vehicle speed signal via CAN communication.
WARNING LAMP	OFF/On	Displays the control status of power steering warning lamp.
STEERING ANGLE SENSOR STATUS	ABNORMAL/NORMAL	Displays the status of steering angle based on the steering angle status signal transmitted via CAN communications.
ENGINE STATUS	STOP/RUN/CRANK	Displays the engine status based on the engine status signal transmitted via CAN communications.
HEAT PROTECT STATUS	NORMAL/PRTECT	Displays the status of overheat protection.
ST TORQUE FLAG	Off/On	Displays the status of power steering system off.
STOP/START STATUS	INACT/ACT	Displays the power steering system status.
Command steering angle	-	NOTE: Displays but not used.
Current steering angle	-	NOTE: Displays but not used.
PA status	-	NOTE: Displays but not used.
PA ST angle valid status	-	NOTE: Displays but not used.
Target motor current	A	Displays the target motor current value.
ST speed valid status	-	NOTE: Displays but not used.
Control gain	-	NOTE: Displays but not used.
Steering control request status	-	NOTE: Displays but not used.
Steering force judgment	-	NOTE: Displays but not used.
EPS status	-	NOTE: Displays but not used.
EPS control (ADAS)	-	NOTE: Displays but not used.
Steering wheel	-	NOTE: Displays but not used.