Description and Operation

Description

EPS (Electric power steering, Column assist type) system uses an electric motor to assist the steering force and it is an engine operation independent steering system.

EPS control module controls the motor operation according to information received from the each sensor and CAN (Controller Area Network), resulting in a more precise and timely control of steering assist than conventional engine-driven hydraulic systems.

Components (Torque Sensor, Fail-safe relay, etc.) of the EPS system are located inside the steering column & EPS unit assembly and the steering column & EPS unit assembly must not be disassemble to inspect or replace them.

Operation

Note With Regard to diagnosis

Trouble factor	Check item	Trouble symtom	Explanation	Note
Drop, impact, and overload	Motor	Abnormal noise	- Visable or unvisable damage can occur.The steering wheel could pull to one side by using the dropped parts. - Precise parts of motor/ECU are sensitive to vibration and impact. - Overload can cause unexpected damage	- Do not use the impacted EPS. - Do not overload each parts.
	ECU	Circuit damage - Wrong welding point - Broken PCB - Damaged precise parts
	Torque sensor	Insufficient steering effort	Overload to INPUT shaft can cause malfunction of the torque sensor	- Do not impact the connecting parts (When inserting and torquing) - Use the specified tool to remove the steering wheel. (Do not hammer on it) - Do not use the impacted EPS
	Shaft	Insufficient steering effort (Uneven between LH and RH)		Do not use the impacted EPS
Pull/Dent	Harness	- Malfunction-impossible power operation - Malfunction of EPS	Disconnection between harness connecting portion and harness	Do not overload the harness
Abnormal storage temperature	Motor/ECU	Abnormal steering effort by improper operation of the motor/ECU	- Waterproof at the normal condition - Even a little moisture can cause malfunction of the precise parts of the motor/ECU	- Keep the normal temperature and proper moisture, while storaging - Avoid drowning

Schematic Diagrams

Schematic Diagrams

Terminal Function

Type	Pin No	Description
Battery	1	Battery +
	2	Battery -
VSS	1	IGN
	2	-
	3	-
	4	-
	5	-
	6	-
	7	HIGH CAN
	8	LOW CAN

Components and Components Location

Components Location

1. Steering wheel 2. Steering column 3. MDPS ECU 4. MDPS motor 5. Tie rod end

6. Bellows 7. Steering gear box 8. Dust cover 9. Universal joint

Repair procedures

General Inspection

After or before servicing the EPS system, perform the troubleshooting and test procedure as follows. Compare the system condition with normal condition in the table below and if abnormal symptom is detected, perform necessary remedy and inspection.

Test Conditions		Symptoms	Assist Time	Warning light	Cause	Inspection Item
IG ON/ Engine ON/ Stationary>IG OFF/ Engine OFF/ Stationary		Steering assist failure	-	-	-	Normal
		Steering assist working	120 seconds	Light is on	IG power is supplied even when the IG is switched off. Steering angle is not initialized	Check IG power line Use a scan tool to initialize steering angle
				Light is off	IG power is supplied even when the IG is switched off. Steering angle is not initialized  &Failure in cluster.	Check cluster wiring line Check Ignition power line Use a scan tool to initialize steering angle
			70 seconds	Light is on	CAN BUS OFF or No EMS signals received	Check CAN communication line
				Light is off	(CAN BUS OFF or No EMS signals received ) & Failure in cluster	Check CAN communication line Check cluster wiring line.
IG ON/ Engine OFF/ Stationary	-	Steering assist failure	-	-	-	-
		Steering assist working	Duration	Light is on	CAN BUS OFF or No EMS signals received	Check CAN communication line
				Light is off	(CAN BUS OFF or No EMS signals received) & Failure in cluster	Check CAN communication line Check cluster wiring line
	When engine is turned on, IG stays at On, but engine goes off		Duration	Light is on	CAN BUS OFF or EMS signals received	Check CAN communication line
			120 seconds	Light is off	-	Normal
IG ON/ Engine ON/ Stationary		Steering assist failure	-	Lght is on	Faults in power supply of EPS system and Ignition	Check the power lines of EPS system and Ignition
			-	Lght is on	Diagnostic trouble code (DTC) appears	Use scanner to diagnose and troubleshoot
		Steering assist working	-	-	-	Normal
			-	Lght is on	Diagnostic trouble code (DTC) appears	Use scanner to diagnose and troubleshoot

IG : Ignition

ASP : Absolute Steering Position

CAN : Controller Area Network

EMS : Engine Management System

ASP (Absolute Steering Position) calibration or EPS type recognition

• Check if the battery is fully charged before ASP calibration or EPS type recognition. • Be careful not to disconnect any cables connected to the vehicle or scan tool during ASP calibration or EPS type recognition. • When the ASP calibration or EPS type recognition is completed, turn the ignition switch off and wait for several seconds, then start the engine to confirm normal operation of the vehicle.

ASP Calibration

1.	Connect self-diagnosis connector(16pins) located in the lower of driver side crash pad to self-diagnosis device.

2.	Turn the self-diagnosis device after key is ON.

3.	After Selecting the "vehicle model" and "system", select the "ASP Calibration" on GDS vehicle selection screen.

EPS Type Recognition

1.	Connect self-diagnosis connector(16pins) located in the lower of driver side crash pad to self-diagnosis device.

2.	Turn the self-diagnosis device after key is ON.

3.	After Selecting the "vehicle model" and "system", select the "EPS Type Recognition" on GDS vehicle selection screen.

Steering Column and Shaft Repair procedures

Removal

1.	Disconnect the battery negative cable from the battery and then wait for at least 30 seconds.

2.	Turn the steering wheel so that the front wheels are placed in the straight ahead position.

3.	Remove the driver airbag module(DAB). • Insert the end of the flat tool along the guide hole. (?5mm allen wrench recommend.) • After inserting the tool, lightly press it. Can be easily remove the air bag module.

4.	Disconnect the airbag module connector (A) and horn connector (B). • The removed airbag module should be stored in a clean, dry place with the pad cover facing up.

5.	Disconnect the connector(A) and then remove the steering wheel by loosening the lock bolt (A). • Do not reuse the steering lock bolt. • When assembling, match the gear teeth as the below illustration.

6.	Loosen the screw and then remove the steering column upper (A) and lower shroud (B).

7.	Disconnect the connector and then sepearte the clock spring (A).

8.	Disconnect the multifunction switch connector.

9.	Loosen the screw and then remove the multifunction switch.

10.	Remove the crash pad lower panel. (Refer to Body - "Crash Pad")

11.	Remove the fixed clip and then remove the wiring from the steering column.

12.	Disconnect MDPS ECU connector.

13.

Loosen the bolt (A) and then disconnect the universal joint assembly from the pinion of the steering gear box. Tightening torque : 32.4 ~ 37.3 N.m (3.3 ~ 3.8 kgf.m, 23.9 ~ 27.5 lb-ft) • Do not reuse the bolt. • Lock the steering wheel in the straight ahead position to prevent the damage of the clock spring inner cable. • When assembling, insert the shark pin into the universal joint york slot as the below illustration.

14.	Remove the steering column & EPS unit assembly by loosening the mounting bolt (B) and nuts (A). Tightening torque Nut : 25.0 ~ 29.4 N.m (2.5 ~ 3.0 kgf.m, 14.5 ~ 21.7 lb-ft) Bolt : 44.1 ~ 49.0 N.m (4.5 ~ 5.0 kgf.m, 32.5 ~ 36.2 lb-ft)

Disassembly

1.	Loosen the bolt (A) and then disconnect the universal joint assembly from the steering column assembly. Tightening torque : 49.0 ~ 58.8 N.m (5.0 ~ 6.0 kgf.m, 39.8 ~ 43.4 lb-ft)

2.	To reassembly, reverse the disassembly procedure.

3.	Reassembly is the reverse of the disassembly. • Do not reuse the universal joint bolt. When assembling, match the gear teeth as the below illustration.

Installation

1.	To install, reverse the removal procedure.

2.	Connect self-diagnosis connector(16pins) located in the lower of driver side crash pad to self-diagnosis devic.

3.	Conduct the "ASP Calibration".

4.	Conduct the "EPS Type Recognition".

Steering Gear box Repair procedures

Removal

1.	Loosen the wheel nuts slightly.

2.	Raise the vehicle, and make sure it is securely supported.

3.	Remove the front wheel and tire (A) from front hub. Tightening torque : 107.9 ~ 127.5 N.m (11.0 ~ 13.0 kgf.m, 79.6 ~ 94.0 lb-ft) • Be careful not to damage the hub bolts when removing the front wheel and tire (A).

4.	Disconnect the stabilizer link with the front strut assembly after loosening the nut (A). Tightening torque : 98.1 ~ 117.7 N.m (10.0 ~ 12.0 kgf.m, 72.3 ~ 86.8 lb-ft) • When loosening the nut (A), fix the outer hexagon of stabilizer bar link. • Be careful not to damage the stabilizer link boots.

5.	Remove the tie rod end ball joint. (1) Rmove the split pin (C). (2) Loosen the nut (B). (3) Using SST(09568-1S100), separate the ball joint (A) from the knuckle. Tightening torque : 23.5 ~ 33.3 N.m (2.4 ~ 3.4 kgf.m, 17.4 ~ 24.6 lb-ft)

6.	Loosen the lower arm nut (A) and then remove the lower arm ball joint by using SST(09568-1S100). Tightening torque : 58.8 ~ 70.6 N.m (6.0 ~ 7.2 kgf.m, 43.4 ~ 52.1 lb-ft) Do not reuse the lower arm lock nut(A).

7.

Loosen the bolt (A) and then disconnect the universal joint assembly from the pinion of the steering gear box. Tightening torque : 32.4 ~ 37.3 N.m (3.3 ~ 3.8 kgf.m, 23.9 ~ 27.5 lb-ft) • Do not reuse the bolt. • Lock the steering wheel in the straight ahead position to prevent the damage of the clock spring inner cable. • When assembling, insert the shark pin into the universal joint york slot as the below illustration.

8.	Remove the roll rod stopper (A) by loosening the bolt and nut. Tightening torque : 107.9 ~ 127.5 N.m (11.0 ~ 13.0 kgf.m, 79.6 ~ 94.0 lb-ft)

9.	Remove the muffler rubber hanger (A).

10.	Remove the subframe by loosening the mounting bolts and nuts. Tightening torque Sub frame mounting bolts and nut : 156.9 ~ 176.5 N.m (16.0 ~ 18.0 kgf.m, 115.7 ~ 130.2 b-ft) Sub frame stay mounting bolt : 44.1 ~ 53.9 N.m (4.5 ~ 5.5 kgf.m, 32.5 ~ 39.8 lb-ft) • Set a transmission jack for safety.

11.	Loosen the mounting bolts and then remove the stabilizer bar (A). Tightening torque : 44.1 ~ 53.9 N.m (4.5 ~ 5.5 kgf.m, 32.5 ~ 39.8 lb-ft)

12.	Remove the protector (A). Tightening torque : 6.9 ~ 10.8 N.m (0.7 ~ 1.1 kgf.m, 5.1 ~ 8.0 lb-ft)

13.	Remove the steering gearbox from the front sub frame by loosening the mounting bolts. Tightening torque : 88.2 ~ 107.8 N.m (9.0 ~ 11.0 kgf.m, 65.0 ~ 79.5 lb-ft)

14.	To install, reverse the removal procedure.

15.	Check the front alignment. (Refer to Suspension System - "Front Alignment")

Replacement

• Do not disassembly the steering gear box. • If disassembly the steering gear box, the quality(Noise / cleanliness / functions) is not guaranteed.

Tie rod end

1.	Remove the tie rod end after loosening the nut. Tightening torque : 49.0 ~ 53.9 N.m (5.0 ~ 5.5 kgf.m, 36.2 ~ 39.8 lb-ft) • Before removing the tie rod end, note by measuring the length of the thread or marked with paint.

2.	Replace with new parts.

3.	Check the alignment. (Refer to Tires/ Wheels - "Alignment")