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Hyundai C1705

MDPS ECU (or Power Pack Assy). If DTC returns, rep

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceService evaluation is appropriate because the verified repair path involves diagnosis of the MDPS ECU wiring/connectors and possible ECU or Power Pack assembly replacement.
Confidence95%

Quick answer

Hyundai DTC C1705 is identified in verified Hyundai service communications as an MDPS ECU hardware error. For the applicable vehicles covered by the communications, the documented process is to erase the DTC, check ECU wiring and connectors, and replace the C-MDPS ECU (or Power Pack assembly) if the DTC returns.

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 C1705 mean?

Hyundai DTC C1705 is identified in verified Hyundai service communications as an MDPS ECU hardware error. For the applicable vehicles covered by the communications, the documented process is to erase the DTC, check ECU wiring and connectors, and replace the C-MDPS ECU (or Power Pack assembly) if the DTC returns.

2. Technical explanation

MDPS refers to the Motor-Driven Power Steering system. Verified Hyundai communications classify C1705 as an ECU hardware error. The available evidence directs technicians to first erase the DTC and inspect the wiring and connector at the ECU. If C1705 returns, the communication directs replacement of the C-MDPS ECU or Power Pack assembly. The evidence does not establish a more specific internal component failure.

3. What system is affected?

Motor-Driven Power Steering (MDPS), specifically the MDPS electronic control unit (ECU) / Power Pack assembly.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • A warning lamp illuminated with DTC(s) present is referenced in the applicable R-MDPS diagnostic flowchart.
  • Additional driver-visible symptoms for C1705 are not yet established by verified evidence.

6. Possible causes

  • MDPS ECU hardware error.
  • Wiring or connector condition at the ECU must be checked before replacement, according to the verified Hyundai communication.

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

  • Have the vehicle diagnosed using the applicable Hyundai MDPS service procedure.
  • Do not attempt ECU or steering-system repair unless qualified to perform vehicle steering-system service.
  • Record any warning lamps and have the stored DTCs checked.

10. Step-by-step troubleshooting

  1. Erase the DTC.
  2. Check the wiring and connector at the ECU.
  3. If C1705 returns, replace the C-MDPS ECU or Power Pack assembly, as directed by the Hyundai communication.

11. When to contact service

Service evaluation is appropriate because the verified repair path involves diagnosis of the MDPS ECU wiring/connectors and possible ECU or Power Pack assembly replacement.

12. What the service center may check

  • Confirm C1705 is stored.
  • Erase the DTC and recheck for its return.
  • Inspect the wiring and connector at the MDPS ECU.
  • Follow the applicable Hyundai MDPS diagnostic flowchart.

13. Possible repair or resolution

  • If C1705 returns after the documented initial checks, replace the C-MDPS ECU or Power Pack assembly.
  • The verified evidence does not establish which assembly is required for every vehicle configuration.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Hyundai TSB 20-ST-001H-1, published August 10, 2020: identifies C1705 as an ECU hardware error and directs erasing the DTC, checking ECU wiring/connectors, and replacing the C-MDPS ECU or Power Pack assembly if the DTC returns.
  • Hyundai TSB 20-ST-001H-2, published September 9, 2020: contains the same C1705 classification and repair direction.
  • Hyundai TSB 22-ST-001H, published January 6, 2022: its R-MDPS flowchart lists C1705 among Power-Pack-related DTCs and directs Power Pack assembly replacement after the applicable diagnostic checks.

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Official NHTSA-hosted Hyundai manufacturer communications: 20-ST-001H-1 (https://static.nhtsa.gov/odi/tsbs/2020/MC-10179244-0001.pdf), 20-ST-001H-2 (https://static.nhtsa.gov/odi/tsbs/2020/MC-10180981-0001.pdf), and 22-ST-001H (https://static.nhtsa.gov/odi/tsbs/2022/MC-10207815-0001.pdf). Verified applicability records include US-market Hyundai Kona model years 2016–2021 and Hyundai Sonata model years 2016–2021; the cited 22-ST-001H communication specifically references 2015–2017 Sonata LFA/LF HEV/PHEV in the available excerpt.

19. Frequently asked questions

What does Hyundai C1705 mean?

Verified Hyundai communications define C1705 as an MDPS ECU hardware error.

What repair does Hyundai specify if C1705 returns?

The verified communications direct replacement of the C-MDPS ECU or Power Pack assembly if the DTC returns after the initial erase and wiring/connector checks.

Does C1705 affect EV battery charging?

Not yet established by verified evidence. The available evidence concerns the MDPS steering system, not charging.

Is C1705 covered by a recall?

Not yet established by verified evidence.

20. Sources & verification

Verified
Hyundai C1705: MDPS ECU (or Power Pack Assy). If DTC returns, rep | EV Diagnostics