Hyundai Santa Cruz: Motor Driven Power Steering / Repair procedures

- Inspection Before and after servicing the MDPS 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 condition	Normal condition: Motor must not supply steering assist.
	Symptom	Possible cause	Remedy
IG Off	Motor supplies steering assist.	SAS is not calibrated.	Perform the SAS calibration using a scan tool.
		IG power supplies	Inspect the IG power supply line.

Test condition	Normal condition: Motor must not supply steering assist, Warning lamp is illuminated.
	Symptom	Possible cause	Remedy
IG On/Engine Off	Motor supplies steering assist.	SAS is not calibrated.	Perform the SAS calibration using a scan tool.
		EMS CAN signal is not received.	Inspect the CAN line.
	Warning lamp is not illuminated.	Cluster fault	Inspect the cluster and cluster harness.

Test condition	Normal condition: Motor supplies steering assist, Warning lamp is not illuminated.
	Symptom	Possible cause	Remedy
IG On/Engine On	Warning lamp is illuminated and motor does not supply steering assist.	MDPS (Hot at all times) and IG power supply fault	Inspect the connector and harness for MDPS (Hot at all times) and IG power supply line.
		DTC is detected by system.	Perform the self test using a scan tool and repair or replace.
	Warning lamp is illuminated and motor supplies steering assist.	ASP is not calibrated.	Perform the MDPS calibration using a scan tool.
		CAN communication between MDPS and cluster is fault.	Inspect the CAN line.
		DTC is detected by system	Perform the self test using a scan tool and repair or replace.

SAS : Steering Angle Sensor CAN : Controller Area NetworkEMS : Engine Management System

   

The following symptoms may occur during normal vehicle operation and if there is no MDPS warning light illumination, the MDPS system is not malfunctioning.

• After switching the ignition on, the steering wheel becomes heavier for about 2 seconds to perform MDPS system diagnostics, and then returns to normal steering condition.

• When switching on or off the ignition, the MDPS relay noise may occur, which is considered normal.

• If the vehicle is steered in stationary or low speed driving condition, motor noise may occur, which is considered normal.

- A/S Repair produres MDPS System A/S Workflow ※ For detailed DTC or other DTC A/S procedures, see "MDPS DTC Diagnostic Guide"

① Noise / malfunction Inspection

② Warning lamp (DTC) / CAN Line error 2 - 1 Checking Connectors and Wiring

1.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 and then check the wiring on the TAS side (A) and ECU side (B).

– 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 "MDPS DTC Diagnostic Guide"

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

③ MDPS Performance Inspection

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

2.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
U/joint bolt mount defect	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	M8 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.