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Hyundai C1688

MDPS ECU (or Power Pack Assy). If DTC returns and MDPS operation is normal, continue investigation into wiring issues. For TMa, if C1688 occurs along wit h C1700, replace Power Pac

DriveNot yet established by verified evidence.
ChargeNot yet established by verified evidence.
ServiceService is indicated by the manufacturer communication when C1688 returns: replacement direction depends on MDPS operation and, for TMa, whether C1700 is also present.
Confidence95%

Quick answer

Hyundai DTC C1688 is identified in the supplied manufacturer communications as a VSM signal error in the MDPS (motor-driven power steering) context. The bulletin directs different next steps based on whether MDPS is inoperable or operating normally 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 C1688 mean?

Hyundai DTC C1688 is identified in the supplied manufacturer communications as a VSM signal error in the MDPS (motor-driven power steering) context. The bulletin directs different next steps based on whether MDPS is inoperable or operating normally if the DTC returns.

2. Technical explanation

Verified Hyundai service-bulletin evidence labels C1688 as “VSM signal error.” If C1688 returns and MDPS is inoperable, the bulletin directs replacement of the C-MDPS ECU (or Power Pack Assy). If C1688 returns and MDPS operation is normal, the bulletin directs continued investigation into wiring issues. For TMa, if C1688 occurs together with C1700, the bulletin directs replacement of the Power Pack Assy.

3. What system is affected?

MDPS / C-MDPS (motor-driven power steering), including the MDPS ECU or Power Pack Assy. The supplied evidence also identifies the code as a VSM signal error.

4. How serious is this code?

Not yet established by verified evidence.

5. Symptoms you may notice

  • A returned C1688 with MDPS inoperable is addressed by the supplied bulletin.
  • Normal MDPS operation despite a returned C1688 is also specifically addressed by the supplied bulletin.

6. Possible causes

  • VSM signal error.
  • Wiring issues are to be investigated when C1688 returns and MDPS operation is normal.
  • The supplied evidence does not establish a more specific wiring fault or root cause.

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

  • Arrange diagnosis by a Hyundai-qualified service facility using the applicable manufacturer procedure.
  • Do not perform high-voltage repair work; the supplied evidence does not identify this as a high-voltage-system DTC.

10. Step-by-step troubleshooting

  1. Confirm whether C1688 returns after diagnosis or repair.
  2. Determine whether MDPS is inoperable or operating normally when C1688 returns.
  3. If C1688 returns and MDPS operation is normal, continue investigation into wiring issues, as directed by the bulletin.
  4. For TMa, check whether C1700 is also present; the supplied bulletin gives a specific Power Pack Assy replacement direction for that combination.

11. When to contact service

Service is indicated by the manufacturer communication when C1688 returns: replacement direction depends on MDPS operation and, for TMa, whether C1700 is also present.

12. What the service center may check

  • Read and document stored DTCs, including whether C1700 is present.
  • Assess whether MDPS is inoperable or operating normally when C1688 returns.
  • Investigate wiring issues when C1688 returns with normal MDPS operation.
  • Follow the applicable Hyundai C-MDPS component-replacement procedure.

13. Possible repair or resolution

  • If C1688 returns and MDPS is inoperable, replace the C-MDPS ECU or Power Pack Assy, per the supplied bulletin.
  • If C1688 returns and MDPS operation is normal, continue investigation into wiring issues.
  • For TMa, if C1688 occurs with C1700, replace the Power Pack Assy.

14. Affected vehicles

15. Related TSBs / service bulletins

  • Hyundai TSB 20-ST-001H-2, published September 9, 2020; NHTSA Manufacturer Communication 10180981: https://static.nhtsa.gov/odi/tsbs/2020/MC-10180981-0001.pdf
  • Hyundai TSB 20-ST-001H-1, published August 10, 2020; NHTSA Manufacturer Communication 10179244: https://static.nhtsa.gov/odi/tsbs/2020/MC-10179244-0001.pdf

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

The verified evidence consists of Hyundai manufacturer communications published through NHTSA. These communications provide component-replacement and wiring-investigation direction for C1688 in the C-MDPS context. Applicability supplied in the database: US-market Hyundai Kona model years 2016–2021 and Hyundai Sonata model years 2016–2021; overlapping year ranges were supplied and have been consolidated here.

19. Frequently asked questions

What does Hyundai code C1688 mean?

The supplied Hyundai bulletin identifies C1688 as a VSM signal error in the MDPS context.

What if C1688 returns and the power steering does not operate?

The supplied bulletin directs replacement of the C-MDPS ECU or Power Pack Assy if C1688 returns and MDPS is inoperable.

What if C1688 returns but MDPS operates normally?

The supplied bulletin directs continued investigation into wiring issues.

Does C1688 with C1700 change the repair?

For TMa, the supplied bulletin directs replacement of the Power Pack Assy when C1688 occurs with C1700.

Is C1688 covered by a recall?

Not yet established by verified evidence.

20. Sources & verification

Verified
Hyundai C1688: MDPS ECU (or Power Pack Assy). If DTC returns and MDPS… | EV Diagnostics