TECHNICAL SERVICE BULLETIN: TRANSMISSION FLUID APPLICATION GUIDE - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides information relating to the correct transmission fluid type and fill quantity requirement for each Kia model. A flush is required ONLY when a transmission is replaced, and the transmission oil cooler is transferred to the new transmission.
full bulletin at NHTSA ↗2021 Kia Niro powertrain problems
moderate Owners of the 2021 Kia Niro have filed 3 NHTSA complaints about the powertrain at roughly $2,500 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See powertrain across all vehicles →
Complaints
3
Recalls
0
Avg fix
$2,500
| Model year | powertrain complaints |
|---|---|
| 2021 Niro (this page) | 3 |
| 2022 Niro | 4 |
| 2023 Niro | 5 |
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering powertrain on this vehicle — documented repair instructions, service campaigns, or warranty extensions sent to dealers. A TSB isn't a recall (it's not a free safety remedy), but it's the manufacturer acknowledging the issue and how to fix it.
This bulletin provides information relating to the correct transmission fluid type and fill quantity requirement for each Kia model. A flush is required ONLY when a transmission is replaced.
full bulletin at NHTSA ↗TECHNICAL SERVICE BULLETIN: TRANSMISSION FLUID APPLICATION GUIDE - This bulletin provides information relating to the correct transmission fluid type and fill quantity requirement for each Kia model. A flush is required ONLY when a transmission is replaced, refer to applicable vehicles in the chart starting on page 2.
full bulletin at NHTSA ↗TECHNICAL SERVICE BULLETIN: SERVICE ACTION: HCU/LDC LOGIC IMPROVEMENT FOR P-DTC (SA484) - This bulletin provides the procedure to update the software logic of the Hybrid Control Unit/Low Voltage DC/DC Converter (HCU/LDC) system on some 2020-2021MY Niro HEV (DE HEV) and Niro PHEV (DE PHEV) vehicles produced in the date ranges shown below, which may incorrectly set a Power Train Diagnostic Trouble Code (P-DTC).
full bulletin at NHTSA ↗TECHNICAL SERVICE BULLETIN: 6-SPEED DCT SHIFT IMPACT/NOISE INSPECTION AND OIL REPLACEMENT - This bulletin provides the inspection method and procedure on some 2019-2020MY Niro (DE HEV/PHEV) vehicles equipped with 6-speed Dual Clutch Transmission (DCT), produced after January 11, 2019, which may exhibit an intermittent noise and/or shift impact. The shift impact may be a noticeable âÂÂshift shockâÂÂ, âÂÂclunkâÂÂ, or other abnormal symptom felt when the vehicle starts after a complete stop.
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
What owners are reporting 3 most recent
This is a hybrid vehicle. It has Dual clutch transmission. Since I have owned it, intermittently the clutch does not disengage completely. This causes the vehicle to try to pull ahead but my foot is on the brake. The vehicle does not stall. Somehow it figures out it can't pull ahead and somehow fully releases. I have brought it to kia at least 3 times. In each case they tell me they cNt get the…
EV motor and drive train have a clattering noise, much like a playing card attached to a bicycle clattering against the wheel spokes. it speeds up and slows down with the acceleration of the motor.
I received important safety recall letter for NHTSA recall # 23V534. the HCA & or Fuse might need to be replaced . I brought the 2021 Nero to my local Kia dealership, Eagle kia ,Riverhead NY on January 18th. The dealership still has the vehicle & claims that a code came up when they did the diagnostics That requires a part that must be secured to complete the fix for the recall. they claim…
Had powertrain trouble with your 2021 Kia Niro?
File a complaint with NHTSA → It's free, official, and how every report above got here — owner filings are the federal safety record this page is built on.
Common questions
How serious is the powertrain problem on the 2021 Kia Niro?
It's a documented issue but not catastrophic. 3 complaints have been filed. Repairs average $2,500 and most owners catch it before it causes a breakdown.
At what mileage does the powertrain typically fail?
Mileage data is limited for this issue. Owners report failures across a wide range, suggesting cause is more about driving conditions and maintenance than mileage alone.
What does it cost to fix?
Independent shops typically charge around $2,500 for powertrain repairs on this vehicle. Dealer pricing tends to run 20-40% higher. The exact figure depends on the specific failure mode, parts availability, and your local labor rates. If you're outside factory warranty, an extended service contract often covers this category.
Are there any recalls related to powertrain?
No active recalls currently cover powertrain issues on this vehicle. The complaints filed represent owner-reported failures that haven't risen to the level of a manufacturer-issued recall — but they're still worth knowing about before you buy or budget for repairs.
Related
Complaint and recall data sourced from the National Highway Traffic Safety Administration (NHTSA)
public records database. Verify the raw federal record at
nhtsa.gov/vehicle/2021/Kia/Niro.
Severity ratings are derived from reported crashes, fires, injuries, and fatalities. Repair cost estimates are
independent-shop national averages and may differ in your area. Some links on this page are affiliate links.