Hyundai Elantra CN7: Motor Driven Power Steering

Seventh generation (CN7; 2021–2025) / Hyundai Elantra CN7 2021-2025 Workshop Manual / Steering System / Motor Driven Power Steering

Description and operation

Description

MDPS (Motor Dirven Power Steering) system uses an electric motor to assist the steering force and it is an engine operation independent steering system.

MDPS 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 (Steering Angle Sensor, Torque Sensor, Fail-safe relay, etc.) of the MDPS system are located inside the steering column. MDPS unit assembly, steering column, and MDPS unit assembly must not be disassembled for inspection. They must be replaced if necessary.

Components and components location

Components

1. Steering wheel
2. Steering column
3. MDPS power pack
4. Universal joint

5. Dust cap
6. Tie rod end
7. Bellows
8. Steering gear box

Schematic diagrams

Schematic Diagrams

C-MDPS

Terminal function

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

Repair procedures

A/S Repair produres

MDPS System A/S Workflow

※ For detailed DTC or other DTC A/S procedures, see "CN7 MDPS DTC Diagnostic Guide"

① Noise / malfunction Inspection

② Warning lamp (DTC) / CAN Line error

2 - 1 Checking Connectors and Wiring

Checking Connectors and Wiring.

Check for damage, push-back, or improper connection in each connector and wiring.

(1)

Check the wiring on the vehicle side.

–	Check for open / short - circuit due to faulty connection, damage, or foreign substance.

(2)

Check the motor connector.

–	Terminal Expansion and damage

•	Must be replaced the MDPS motor if occur terminal expansion and damage. (Refer to Motor Driven Power Steering - "MDPS Power Pack Assembly")

(3)

Remove the grommet (A) and then check the wiring on the TAS side (B) and ECU side (C).

–	Check for damage, push-back, or improper connection in each connector and wiring.

•	For DTC C125901 / C125929 / C125938 / C129002, exchange MDPS wiring. (Refer to Motor Driven Power Steering - "MDPS Wiring")

•	If problems are found during the MDPS wiring check, replace the MDPS column & housing. (Refer to Motor Driven Power Steering - "MDPS Column & Housing")

2 - 2 Inspection Items per DTC

※ For detailed DTC or other DTC A/S procedures, see "CN7 MDPS DTC Diagnostic Guide"

DTC	Problem	First analysis method	How to repair
C129002	Torque sensor signal error	First erase DTC,	When the sensor connector flows, the warning lamp reoccurs Replace the sensor cable, and replace the column & housing (56390)
C129002	Torque sensor signal error	check connector connection
C125901	Steering angle signal error	Earase DTC after resetting Steering angle zero point
C125929		check connector connection
C125938
C111201	Torque sensor power supply error	First erase DTC, check connector connection	When the sensor connector flows, the warning lamp reoccurs Replace the sensor cable, and replace the power pack (56370)
C160404	ECU hardware error	Check after erasing the DTC	In case of reoccurrence, replace MDPS power pack (56370)
C170401	Relay breaking of a wire
C170504	ECU over/discharge error
C241216	Motor circuit break / short
C241262	Motor current error
C241319	Over current error
C241328	Motor electric current gate error
C241396	Broken the motor current sensor
C240162	Motor circuit error
C126154	Steering angle zero point error	Check after resetting Steering angle zero point	Resetting Steering angle zero point or replace column & housing (56390)
C126154	Steering angle zero point error	Check sensor connector poor connect
C161187	Not received the EMS CAN message	1. Check chassis CAN condition
C161F64	Vehicle speed monitoring error	2. Check connector connection	Earase DTC (No MDPS replacement)
C161F86	Vehicle speed signal error	3. Check engine ECU
C161688	CAN BUS OFF	4. Start OFF history confirmation message while driving
C162887	Not received the cluster CAN signal	2. Check cluster connector connection
C163386	Cluster display vehicle speed error	2. Check cluster connector connection
C169287	Not received the VSM message	Check ESC, check chassis CAN condition
C169386	ESC signal error	Check ESC, check chassis CAN condition
C171101	ECU abnormal end	Recheck after erasing the DTC
C180487	Cannot be received the LKA message	Check LKA, check CAN line
C180586	LKA signal error	Check LKA, check CAN line
C181287	Not received the gateway CAN message	Check gateway
C181786	Gateway CAN signal error	Check gateway

③ MDPS Performance Inspection

1.	Inspect steering angle and DTCs relevant to the steering system.

Inspection for heavy steering effort

(1)	Inspect tire pressure and width.

(2)	Check DTCs relevant to the CAN communication error.

(3)	Check the wheel alignment.

④ MDPS common problems

Case 1	Case 2	Case 3

Multifunction switch noise	Clock spring noise	DAB / Wire noise
Retighten the bolt	Replace clock spring	Rearrange and replace DAB

Case 4	Case 5	Case 6

Multifunction switch noise	MB nut mount defect	M10 nut mount defect
Replace multifunction switch	Retighten nut	Retighten nut

Case 7	Case 8

Cowl top bolt mount defect	Cowl bar nut mount defect
Retighten cowl top bolt	Replace clock spring

Cautions to be taken when handling the MDPS (Motor Driven Power Steering)

•	Failure occurs due to internal damage because of the drop of and shock and excessive external force on the new partial component. → Be cautious of shock on the partial component and replace the damaged part (due to drop, etc.) with a new one.

•	When fastening the steering, excessive impact may result in twisting the center point of the torque sensor.

•	When removing/installing the connector the wiring may be damaged (deformed) by excessive external force.

•	Be cautious when storing and replacing the partial components under the abnormal temperature and humidity conditions.

MDPS PowerPack Assembly

Repair procedures

Replacement

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

•	If the steering wheel and the front tires are not set straight ahead together, it may affect the number of circulation of steering wheel and damage the cable inside the clock spring.

Turn the ignition switch OFF and disconnect the battery negative (-) cable.

•	Disconnect the battery negative cable from the battery and then wait for at least 3 minutes.

3.	Remove driver airbag (DAB) module. (Refer to Restraint - "Driver Airbag (DAB) Module and Clock Spring")

4.	Remove the steering wheel. (Refer to Steering System - "Steering Wheel")

5.	Remove the clock spring. (Refer to Restraint - "Driver Airbag (DAB) Module and Clock Spring")

6.	Remove the steering column shroud panel. (Refer to Body - "Steering Column Shroud Panel")

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

8.	Remove the brake booster. (Only RHD) (Refer to Brake System - "Brake Booster")

9.	Remove the brake pedal. (Only RHD) (Refer to Brake System - "Brake Pedal")

10.	Disconnect the MDPS connector (A).

11.	Remove the wiring clip (A) from the steering column.

12.

Remove the steering column assembly after loosening the mounting nuts (A) and bolt (B).

Tightening torque

(A) : 25.0 - 29.4 N.m (2.5 - 3.0 kgf.m, 14.5 - 21.7 lb-ft)

(B) : 53.9 - 58.8 N.m (5.5 - 6.0 kgf.m, 39.8 - 43.4 lb-ft)

13.

Remove the MDPS power pack (A) after loosening the bolts.

Tightening torque :

8.0 - 12.0 N.m (0.82 - 1.22 kgf.m, 5.9 - 8.8 lb-ft)

14.

Install the new MDPS powerpack.

•	Check the couple ring (A) whether it is assembled, before installing the new MDPS motor.

15.	To reassembly, reverse the disassembly procedure.

16.	Conduct the "EPS Type Recognition" by diagnostic tool. (Refer to MDPS PowerPack Assembly - "Diagnosis with Diagnostic tool")

17.	Conduct the "ASP Calibration" by diagnostic tool. (Refer to MDPS PowerPack Assembly - "Diagnosis with Diagnostic tool")

18.	Erase DTC.

Diagnosis with Diagnostic tool

EPS Type Recognition

•	When missing the EPS Type Recognition, occure a problem with motor driven power steering performance.

EPS Type Recognition procedures

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.	Turn the steering wheel to straight ahead position.

4.	After Selecting the "vehicle model" and "system", select the "EPS Type Recognition" on diagnostic tool vehicle selection screen.

5.	Remove the DTC.

Turn off the IG switch and wait for 20 seconds or more before starting the engine. And then make sure that MDPS works properly.

SAS Calibration

–	Steering-angle sensor detects the steering angle and steering angle speed. Steering angle and steering angle speed are used for steering wheel damping and return controls in addition to providing assistance torque.

•	You can use a scan tool to (diagnostic tool) check if the battery voltage is proper before perform the "SAS Calibration".

•	Make sure that no connector engaged to the vehicle or scan tool is disconnected during the "SAS Calibration".

•	Once the "SAS Calibration" is complete, turn off the IG switch and wait for 10 seconds or more before starting the engine to check the operation.

SAS Calibration procedures

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.	Turn the steering wheel to straight ahead position.

4.	After Selecting the "vehicle model" and "system", select the "SAS Calibration" on diagnostic tool vehicle selection screen.

5.	Remove the DTC.

6.	Turn off the IG switch and wait for 10 seconds or more before starting the engine. And then make sure that MDPS works properly.

MDPS Column and Housing

Repair procedures

Replacement

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

•	If the steering wheel and the front tires are not set straight ahead together, it may affect the number of circulation of steering wheel and damage the cable inside the clock spring.

Turn the ignition switch OFF and disconnect the battery negative (-) cable.

•	Disconnect the battery negative cable from the battery and then wait for at least 3 minutes.

3.	Remove driver airbag (DAB) module. (Refer to Restraint - "Driver Airbag (DAB) Module and Clock Spring")

4.	Remove the steering wheel. (Refer to Steering System - "Steering Wheel")

5.	Remove the clock spring. (Refer to Restraint - "Driver Airbag (DAB) Module and Clock Spring")

6.	Remove the steering column shroud panel. (Refer to Body - "Steering Column Shroud Panel")

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

8.	Remove the brake booster. (Only RHD) (Refer to Brake System - "Brake Booster")

9.	Remove the brake pedal. (Only RHD) (Refer to Brake System - "Brake Pedal")

10.	Disconnect the MDPS connector (A).

11.	Remove the wiring clip (A) from the steering column.

12.

Separate the universal joint from the steering gear box after loosening the universal joint mounting bolt (A).

Tightening torque :

49.0 - 58.8 N.m (5.0 - 6.0 kgf.m, 36.2 - 43.4 lb-ft)

•	Lock the steering wheel in the straight ahead position to prevent the damage of the clock spring inner cable.

•	When mounting, securely insert the universal joint into the steering gear box pinion shaft.

•	Do not reuse the universal joint bolt.

•	Assemble so that pinion shaft shark pin can be inserted between the joint slots.

•	Install by aligning the machining surface (A) of the universal joint and the machining surface (B) of the steering gearbox pinion shaft.

13.

Remove the steering column assembly after loosening the mounting nuts (A) and bolt (B).

Tightening torque

(A) : 25.0 - 29.4 N.m (2.5 - 3.0 kgf.m, 14.5 - 21.7 lb-ft)

(B) : 53.9 - 58.8 N.m (5.5 - 6.0 kgf.m, 39.8 - 43.4 lb-ft)

14.

Separate the steering column assembly and universal joint assembly after loosening the mounting bolt (A).

Tightening torque :

49.0 - 58.8 N.m (5.0 - 6.0 kgf.m, 36.2 - 43.4 lb-ft)

15.	Disconnet the grommet (A).

16.	Disconnect the MDPS wiring connector (A).

17.

Remove the MDPS power pack (A) after loosening the mounting bolts.

Tightening torque :

8.0 - 12.0 N.m (0.82 - 1.22 kgf.m, 5.9 - 8.8 lb-ft)

•	Check the couple ring (A) whether it is assembled, before installing the new MDPS motor.

18.	To install, reverse the removal procedures.

19.	Set the Steering angle zero point by using the diagnostic tool.

20.	Conduct the "EPS Type Recognition" by diagnostic tool. (Refer to MDPS PowerPack Assembly - "Diagnosis with diagnostic tool")

21.	Conduct the "ASP Calibration" by diagnostic tool. (Refer to MDPS PowerPack Assembly - "Diagnosis with Diagnostic tool")

22.	Conduct the MDPS Performance Inspection using the diagnostic tool. (Refer to Motor Driven Power Steering - "MDPS Performance Inspection")

23.	Check the DTC.

24.	Turn off the IGN switch and wait for 20 seconds or more. Then check the operation after starting the engine.

Small bearing

1.	Remove the crash pad lower panel. (Refer to Body (Interior and Exterior) - "Crash Pad Lower Pannel")

2.	Remove the small bearing cover (A).

3.	Remove the small bearing (A) by rotating in the direction of the arrow after installing the SST (09563-IB000).

4.	Install the new small bearing (A) to the SST (0956-IB200).

Press the small bearing by rotating in the direction of the arrow after installing the SST (09563-IB000).

Tightening torque :

2.0 - 2.9 N.m (0.2 - 0.3 kgf.m, 1.4 - 2.2 lb-ft)

Steering Gear Box

Repair procedures

Removal

1.	Loosen the wheel nuts slightly. Raise the vehicle, and make sure it is securely supported.

Remove the front wheel and tire (A) from the 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).

Remove stabilizer bar link from the front strut after loosening the mounting nut.

Tightening torque :

98.1 - 117.7 N.m (10.0 - 12.0 kgf.m, 72.3 - 86.8 lb-ft)

•	When loosening the nut fix the outer hexagon of stabilizer bar link.

•	Be careful not to damage the stabilizer link boots.

Remove the tie rod end ball joint by using the special service tool.

(1)	Remove the split pin and castle nut (A).

(2)

Remove the tie rod end ball joint (B) by using the SST (09568-1S100).

Tightening torque :

34.3 - 39.2 N.m (3.5 - 4.5 kgf.m, 25.3 - 28.9 lb-ft)

•	Do not resuse castle nut.

Separate the lower arm ball joint by using the SST (09568-1S100) after loosening the lower arm mounting nut (A).

Tightening torque :

68.6 - 80.4 N.m (7.0 - 8.2 kgf.m, 50.6 - 59.3 lb-ft)

•	Do not reuse the lower arm ball joint nut (A).

Separate the universal joint from the steering gear box after loosening the universal joint mounting bolt (A).

Tightening torque :

49.0 - 58.8 N.m (5.0 - 6.0 kgf.m, 36.2 - 43.4 lb-ft)

•	Lock the steering wheel in the straight ahead position to prevent the damage of the clock spring inner cable.

•	When mounting, securely insert the universal joint into the steering gear box pinion shaft.

•	Do not reuse the universal joint bolt.

•	Assemble so that pinion shaft shark pin can be inserted between the joint slots.

•	Install by aligning the machining surface (A) of the universal joint and the machining surface (B) of the steering gearbox pinion shaft.

7.	Remove the engine room under cover. (Refer to Engine Mechanical System - "Engine Room Under Cover")

Remove the heat protector (A).

Tightening torque

8.8 - 12.7 N.m (0.9 - 1.3 kgf.m, 6.5 - 9.4 lb-ft)

9.	Remove the muffler rubber hanger (A).

10.

Remove the roll rod bracket (C) after loosening the mounting bolts (A, B).

Tightening torque

(A) : 107.9 - 127.5 N.m (11.0 - 13.0 kgf.m, 79.6 - 94.0 lb-ft)

(B) : 49.0 - 63.7 N.m (5.0 - 6.5 kgf.m, 36.2 - 47.0 lb-ft)

11.	Remove the fastener (A). [LH] [RH]

12.

Remove the sub frame after loosening the mounting bolts and nuts.

Tightening torque :

176.5 - 196.1 N.m (18.0 - 20.0 kgf.m, 130.2 - 144.7 b-ft)

•	Set a transmission jack for safety.

13.

Remove the heat protector (A).

Tightening torque :

6.9 - 10.8 N.m (0.7 - 1.1 kgf.m, 5.1 - 8.0 lb-ft)

14.

Remove the steering gear box (A) from the sub frame after loosening the mounting bolts.

Tightening torque :

107.9 - 127.5 N.m (11.0 - 13.0 kgf.m, 79.6 - 94.0 lb-ft)

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

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 front alignment. (Refer to Tires / Wheels - "Alignment")

Installation

1.	To install, reverse the removal procedures.

2.	Check the alignment. (Refer to Suspension System - "Alignment")

MDPS Wiring

Repair procedures

Removal

•	For DTC C125901 / C125929 / C125938 / C129002, refer to "CN7 MDPS DTC Diagnostic Guide".

Turn the ignition switch OFF and disconnect the battery negative (-) cable.

•	Disconnect the battery negative cable from the battery and then wait for at least 3 minutes.

2.	Remove the fuse cover (A).

Disconnect the grommet (A) and MDPS connector (B).

•	When removing the connector, separate it as follows.

4.	Remove the wiring after disconnecting the MDPS connector (A).

Installation

1.	To install, reverse the removal procedures.

Steering Wheel (Heated Steering Wheel)

Components and components location Components[G 1.6 MPI / LPI]1. Drive air bag module (DAB)2. Wiring3. Steering wheel4. Damper5. Remote control switch6. Switch bezel7. Lower cover[G 1.6 T-GDI]1. Lo ...

Restraint

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