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Hyundai · Known Issues

2021 Hyundai Ioniq Problems: 4 Known Issues

2021 model year · 560+ owner reports · Updated September 2026

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Issue summary

According to Au7o's analysis of 560+ owner reports, the 2021 Hyundai Ioniq has 4 documented known issues. None of the listed issues is rated critical; this is not a complete reliability assessment. The most commonly reported issue is 6-Speed DCT Harsh Shifting, Shuddering, and Hesitation with 285 owner reports. Across all issues with published estimates, repair costs range from $400 to $3,000. DIY maintenance guides at au7o.io.

In This Article

  • Ioniq Transmission1
  • Ioniq Electrical1
  • Ioniq Brakes1
  • Ioniq Suspension1
  • FAQ
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In This Article

  • Transmission1
  • Electrical1
  • Brakes1
  • Suspension1
  • FAQ

All 4 Known Issues

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ALL YEARS202220212020201920182017
Community reported
285 owners

On the 2017-2022 Hyundai Ioniq, the Hyundai Ioniq Hybrid and PHEV use a 6-speed dual-clutch transmission (DCT) that is prone to harsh shifting, shuddering during low-speed acceleration, and hesitation from a stop. The defect involves the transmission control module (TCM) and the dual-clutch mechanism itself. The clutch can slip, causing the transmission to hesitate or shudder, particularly in hot weather when the clutch overheats. Service records show broken pins and jammed shafts within the DCT components. Hyundai acknowledged the issue by placing warning cards near the gear selector in some vehicles. The defect prevents proper acceleration from a stop, which is dangerous in traffic.

This issue also affects: Hyundai Accent, Hyundai Genesis Coupe, Hyundai Kona

Common Symptoms

  • Shuddering or jerking during acceleration from a stop
  • Hesitation when pressing the accelerator from standstill
  • Harsh or delayed shifts between gears
  • Transmission slips during gear changes
  • Worse performance in hot weather or stop-and-go traffic

How to Fix

Visit a Hyundai dealer for the latest TCM software update, which improves shift logic and clutch engagement timing. If shuddering persists after the software update, the clutch actuator assembly may need replacement ($1,500-$3,000 at dealer, covered under the 10-year/100,000-mile powertrain warranty). Avoid holding the vehicle on hills with the brake released and clutch engaged — use the brake pedal instead. In stop-and-go traffic, the DCT can be managed by being smooth with throttle inputs rather than rapid acceleration. Some owners report improved behavior after a transmission fluid change ($150-$250), though Hyundai considers the fluid lifetime.

Owner tips & cautions

  • TipThe DCT shudder is worst when the clutch is cold and you launch aggressively. Let the car warm up for 2-3 minutes before driving, and be gentle with the throttle from a stop for the first few miles. This dramatically reduces the shuddering.
  • TipIf the dealer says 'that is normal DCT behavior,' push back and ask for the TCM software update. The updated calibration files significantly improve shift quality. Hyundai has released multiple updates and the latest versions are much better than the original software.
Typical repair cost:$0 - $3,000

Research This Issue

Based on 285 owner reports

GoogleRedditYouTubeNHTSA
Community Reported
High Confidence285 owner reportsLast reported by owners Mar 2026Reviewed Mar 2026
Community reported
165 owners

On the 2019-2022 Hyundai Ioniq, the Hyundai Ioniq Hybrid and Plug-In Hybrid models from 2019-2022 can exhibit warning lights and system faults caused by software bugs in the Hybrid Control Unit (HCU) and Low DC/DC Converter (LDC). The issues include communication errors (DTC U1341) between control modules, incorrect battery state-of-charge calculations, and improper power distribution between the electric motor and gasoline engine. Hyundai has released multiple TSBs addressing software logic updates for the HCU and LDC. The Plug-In Hybrid variant is more frequently affected due to its more complex power management between the larger battery, electric motor, and engine.

Common Symptoms

  • Check Engine light with hybrid system-related DTC codes
  • Hybrid system warning indicator on dashboard
  • Unexpected transitions between EV and hybrid modes
  • Reduced power output or EV range
  • 12V battery frequently low despite normal driving

How to Fix

Visit a Hyundai dealer and request the latest HCU and LDC software updates as outlined in Hyundai's Technical Service Bulletins. The software update is free and typically takes 1-2 hours. After the update, the dealer should clear all stored DTCs and verify normal operation. If warning lights return after the software update, a more thorough diagnosis of the high-voltage system may be needed, including inspection of the DC/DC converter output and 12V system charging. Keep the 12V battery in good condition, as a weak 12V battery can trigger false HCU warning lights.

Owner tips & cautions

  • TipWhen you take the Ioniq in for any service, ask the advisor to check for pending software updates. Hyundai releases HCU updates several times per year but does not always notify owners. Getting the latest calibration prevents many phantom warning light issues.
Typical repair cost:$0 - $200

Research This Issue

Based on 165 owner reports

GoogleRedditYouTubeNHTSA
Community Reported
High Confidence165 owner reportsLast reported by owners Mar 2026Reviewed Mar 2026
Community reported
110 owners

On the 2017-2022 Hyundai Ioniq, the Hyundai Ioniq's electronic parking brake (EPB) and Auto Hold feature can malfunction randomly, illuminating the EPB warning light and disabling the Auto Hold function. The EPB system uses brushed DC motors in the rear calipers that can fail prematurely, with diagnostic code C2417 indicating a motor short or open circuit. When the EPB faults, the Auto Hold feature (which automatically holds the brake at stops) also becomes unavailable, turning orange on the dashboard. The issue can be intermittent and difficult for dealers to reproduce, as the fault codes may not store permanently.

Common Symptoms

  • Electronic Parking Brake warning light illuminates randomly
  • Auto Hold indicator turns orange and feature is disabled
  • EPB fails to engage when shifting to Park
  • Grinding or clicking noise from rear brakes when EPB activates
  • Smart Cruise Control becomes unavailable when EPB faults

How to Fix

Visit a Hyundai dealer and request a scan for code C2417. If present, the rear caliper EPB motor needs replacement ($400-$700 per caliper including labor). Both rear calipers should ideally be replaced together as the motors wear at similar rates. The dealer can also perform an EPB service mode reset after replacement. If the issue is intermittent and no codes are stored, ask the dealer to note the complaint in the service record for warranty tracking. The EPB calipers and motors are covered under the factory warranty.

Owner tips & cautions

  • TipIf the EPB warning comes on intermittently, take a photo or video of the dashboard every time it happens. The dealer needs evidence that the issue is recurring if they cannot reproduce it during the service visit. Date-stamped photos strengthen your warranty claim.
Typical repair cost:$400 - $1,400

Research This Issue

Based on 110 owner reports

GoogleRedditYouTubeNHTSA
Community Reported
Medium Confidence110 owner reportsLast reported by owners Mar 2026Reviewed Mar 2026

On the 2017-2022 Hyundai Ioniq, hyundai Technical Service Bulletin 21-ST-003H says certain vehicles may develop bearing noise within the Motor Driven Power Steering (MDPS) column worm shaft assembly. The bulletin applies to 2017-2022 Ioniq Hybrid and Plug-In Hybrid vehicles and 2017-2021 Ioniq Electric vehicles.

Common Symptoms

  • Bearing noise from the Motor Driven Power Steering column worm shaft assembly

How to Fix

Ask a Hyundai dealer to verify whether the noise comes from the C-MDPS worm shaft bearing and, if confirmed, follow TSB 21-ST-003H. The bulletin supersedes an earlier procedure and directs technicians to replace the small worm shaft bearing rather than the worm shaft assembly.

What you need to fix it

Only diagnosis- and fitment-reviewed repair parts are linked here.

  • Genuine Hyundai 56359-L1AAA-FFF C-MDPS small bearing kit
    OEMHyundai 56359-L1AAA-FFF

    small worm-shaft bearing and damper repair after the TSB localization test confirms bearing noise Fitment/availability: TSB 21-ST-003H covers 2017-2022 Ioniq Hybrid/Plug-In Hybrid and 2017-2021 Ioniq Electric.

    HyundaiPartsDeal

As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.

Research This Issue

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Manually Verified
High ConfidenceVerifiedReviewed Aug 2026
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Frequently Asked Questions

What are the most common Hyundai Ioniq problems?

According to Au7o's analysis of 560+ owner reports, the 2021 Hyundai Ioniq has 4 documented issues. The most frequently reported are: 6-Speed DCT Harsh Shifting, Shuddering, and Hesitation, Hybrid Control Unit Software Glitches and Warning Lights, Electronic Parking Brake and Auto Hold Malfunction. None are rated critical, but regular maintenance is recommended.

Is the Hyundai Ioniq reliable?

The 2021 Hyundai Ioniq has 4 known issues documented across 560+ owner reports. None of the matching records is rated critical; this is not a complete reliability assessment. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Hyundai Ioniq problems?

Repair costs for known Hyundai Ioniq issues range from $0 to $3,000, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2017-2022 Hyundai Ioniq 6-Speed DCT Harsh Shifting, Shuddering, and Hesitation?

The Hyundai Ioniq Hybrid and PHEV use a 6-speed dual-clutch transmission (DCT) that is prone to harsh shifting, shuddering during low-speed acceleration, and hesitation from a stop. The defect involves the transmission control module (TCM) and the dual-clutch mechanism itself. Th… Repairs typically run $0-$3,000. Severity: medium.

What is the 2019-2022 Hyundai Ioniq Hybrid Control Unit Software Glitches and Warning Lights?

The Hyundai Ioniq Hybrid and Plug-In Hybrid models from 2019-2022 can exhibit warning lights and system faults caused by software bugs in the Hybrid Control Unit (HCU) and Low DC/DC Converter (LDC). The issues include communication errors (DTC U1341) between control modules, inco… Repairs typically run $0-$200. Severity: medium.

What is the 2017-2022 Hyundai Ioniq Electronic Parking Brake and Auto Hold Malfunction?

Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.

Data sourced from 560+ owner reports, NHTSA recalls, TSBs, and automotive forums.

The Hyundai Ioniq's electronic parking brake (EPB) and Auto Hold feature can malfunction randomly, illuminating the EPB warning light and disabling the Auto Hold function. The EPB system uses brushed DC motors in the rear calipers that can fail prematurely, with diagnostic code C… Repairs typically run $400-$1,400. Severity: medium.

What is the 2017-2022 Hyundai Ioniq Motor Driven Power Steering Column Bearing Noise?

Hyundai Technical Service Bulletin 21-ST-003H says certain vehicles may develop bearing noise within the Motor Driven Power Steering (MDPS) column worm shaft assembly. The bulletin applies to 2017-2022 Ioniq Hybrid and Plug-In Hybrid vehicles and 2017-2021 Ioniq Electric vehicles… Severity: low.