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Hyundai C1603

MDPS ground. Check EMS CAN line. C1616 CAN BUS OFF Check the chassis CAN line. C1622 Vehicle

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceContact a Hyundai dealer or qualified Hyundai service facility if C1603 returns or if assistance is needed with diagnosis. The supplied evidence does not establish a mandatory service requirement.
Confidence95%

Quick answer

For the Hyundai applications supported by the verified TSB evidence, C1603 is an MDPS (motor-driven power steering) thermal-protection code. Hyundai states it protects the motor from overheating; investigate the driving conditions when it set. The cited C-MDPS guidance says no replacement is necessary for C1603.

This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.

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1. What does C1603 mean?

For the Hyundai applications supported by the verified TSB evidence, C1603 is an MDPS (motor-driven power steering) thermal-protection code. Hyundai states it protects the motor from overheating; investigate the driving conditions when it set. The cited C-MDPS guidance says no replacement is necessary for C1603.

2. Technical explanation

The supplied record’s canonical text combines descriptions from multiple codes, but the verified Hyundai/NHTSA TSB evidence specifically identifies C1603 as “MDPS thermal protection.” Hyundai’s diagnostic table states that this DTC protects the motor from overheating. The listed first inspection is to investigate the driving conditions when the DTC set, and the listed repair recommendation is “No replacement necessary.” Another cited Hyundai communication instructs waiting 20–30 seconds for the system to cool down.

3. What system is affected?

Motor-Driven Power Steering (MDPS), specifically C-MDPS in the cited Hyundai diagnostic table.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • Not yet established by verified evidence.

6. Possible causes

  • MDPS motor overheating/thermal protection, as identified in the cited Hyundai diagnostic table.
  • The specific operating or driving conditions that caused the code to set must be investigated; further causes are not established by the supplied verified evidence.

7. Can I still drive the vehicle?

Not yet established by verified evidence.

8. Can I charge the vehicle?

Not yet established by verified evidence.

9. What you can safely do

  • Allow 20–30 seconds for the system to cool down, as stated in the cited Hyundai communication.
  • Have a Hyundai-qualified service facility investigate the driving conditions under which C1603 set.
  • Do not replace MDPS components solely because C1603 is present; the cited C-MDPS table lists no replacement as necessary for this code.

10. Step-by-step troubleshooting

  1. Use Hyundai diagnostic equipment and follow the applicable Hyundai C-MDPS diagnostic procedure.
  2. Investigate the driving conditions present when C1603 set.
  3. The cited material does not establish a user-performed electrical or high-voltage repair procedure.

11. When to contact service

Contact a Hyundai dealer or qualified Hyundai service facility if C1603 returns or if assistance is needed with diagnosis. The supplied evidence does not establish a mandatory service requirement.

12. What the service center may check

  • Confirm the DTC using Hyundai diagnostic equipment.
  • Investigate the driving conditions when the DTC set.
  • Apply the Hyundai C-MDPS diagnostic guidance applicable to the vehicle.

13. Possible repair or resolution

  • For C1603, Hyundai’s cited C-MDPS table states: no replacement necessary.
  • Wait 20–30 seconds for the system to cool down, per the cited Hyundai communication.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Hyundai TSB 23-ST-003H, published April 10, 2023: 2015–2017 Sonata and Sonata Hybrid/Plug-In MDPS warranty-extension diagnostic material; its supplied excerpt identifies C1603 as thermal protection and says to wait 20–30 seconds for cooling.
  • Hyundai TSB 22-ST-001H, published January 6, 2022: 2015–2017 Sonata (LFA, LF HEV/PHEV) MDPS warranty-extension diagnostic material; its supplied excerpt identifies C1603 as thermal protection and says to wait 20–30 seconds for cooling.
  • Hyundai TSB 20-ST-001H-2, published September 9, 2020: C-MDPS DTC table identifies C1603 as MDPS thermal protection; investigate driving conditions; no replacement necessary.
  • Hyundai TSB 20-ST-001H-1, published August 10, 2020: C-MDPS DTC table identifies C1603 as MDPS thermal protection; investigate driving conditions; no replacement necessary.

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Verified sources are Hyundai manufacturer communications published through NHTSA. The supplied diagnostic record lists Hyundai Kona model years 2016–2020 and 2016–2021, plus Hyundai Sonata model years 2016–2020, 2016–2021, and 2016–2017, all for the US. The cited TSB excerpts specifically reference 2015–2017 Sonata and certain Sonata Hybrid/Plug-In applications; exact applicability should be confirmed by VIN and the applicable Hyundai service information.

19. Frequently asked questions

What does Hyundai C1603 mean?

In the supplied Hyundai C-MDPS TSB table, C1603 means MDPS thermal protection and protects the motor from overheating.

Does C1603 require MDPS replacement?

The cited Hyundai C-MDPS diagnostic table states that no replacement is necessary for C1603.

What should be checked for C1603?

Hyundai’s cited first inspection is to investigate the driving conditions when the DTC set.

Is C1603 a CAN-bus code?

No. The supplied Hyundai table identifies C1603 as MDPS thermal protection. The same table separately lists C1611 for EMS CAN timeout and C1616 for CAN BUS OFF.

20. Sources & verification

Verified
Hyundai C1603: MDPS ground. Check EMS CAN line. C1616 CAN BUS OFF… | EV Diagnostics