KiaNiro2021Overview/kia/niro/2021/base/

2021 Kia Niro

Factory specifications, fluid capacities, torque values, EPA fuel economy and the federal safety record for the 2021 Niro.

Transmission Automatic (AM-S6)

The 2021 Kia Niro pairs a 51/46/49 EPA mpg rating with an automatic AM-S6 transmission, anchoring the 2021–2025 complaint window as a fuel-economy-focused entry in the model line. Its reliability record is comparatively quiet: just nine owner complaints and one recall place it near the low end of the observed range, well below the 2023 peak of 40 complaints and comparable to the 2024 low of eight. For researchers, that makes the 2021 model a useful baseline—a relatively uneventful opening year before reported issue volume climbed to its 2023 high.

Model year20252023202220212020201920182017

Quick specs

Fluid capacities, tune-up values and fuel economy at a glance.

EPA fuel economy51/46/49 mpgEPA · verified

Fitment & sizes

Replacement part sizes and factory part numbers — battery, bulbs, filters and belts.

From the factory this vehicle uses a BCI Non BCI Group Size Battery. Li-ion Battery Only. Contact a specialist before removal. battery. Each part links to every other vehicle that shares it, so a part you already stock may fit more of your fleet than you'd expect.

Battery groupBCI Non BCI Group Size Battery. Li-ion Battery Only. Contact a specialist before removal.OEM · verified
Tire size205/60R16 92HOEM · verified
Wheel / rim6.5 inOEM · verified

Full specifications

Engine, drivetrain, dimensions and economy.

Engine & drivetrain NHTSA vPIC

TransmissionAutomatic (AM-S6)

Dimensions & weight NHTSA vPIC

Overall length171.7 in
Overall width70.9 in
Overall height60.6 in
Wheelbase106.3 in
Curb weight3166 lb
Track (front / rear)61.8 / 62.2 in
Weight distribution (front / rear)54/46

Ratings & economy EPA / vPIC

EPA city / highway / combined51 / 46 / 49 mpg
DrivetrainFront-Wheel Drive
Passenger volume101 cu ft
Cargo volume22 cu ft
Recommended fuelRegular Gasoline

Performance & power Independent road tests

0–60 mph, quarter-mile, horsepower and torque from independent road tests.

Independent road tests for the Niro of this era, listed by trim and engine — this page spans more than one engine, so no single horsepower figure is shown.

6.2–10.1 sec0–60 mph (tested)quickest 6.20 sec — 2020 EV EX Premium Hatchback
YearTrim / engine0–60¼ mileHPDrivetrain
2020EV EX Premium Hatchback Elec 64-kWh6.20 sec14.90 sec201 hpFWD
2020EX Premium EcoHybrid Hatchback 1.6L I-4 + Elec 1.56-kWh9.20 sec17.00 sec139 hpFWD
2020EX Premium EcoHybrid Hatchback 1.6L I-4 + Elec 1.56-kWh9.50 sec17.20 sec139 hpFWD
2019EV EX Premium Hatchback Elec 64-kWh6.20 sec14.80 sec201 hpFWD
2019EV EX Premium Hatchback Elec 64-kWh6.50 sec15.10 sec201 hpFWD
2019EV EX Premium Hatchback Elec 64-kWh7.00 sec15.50 sec201 hpFWD
2018EX Premium EcoPlug-in Hatchback 1.6L I-4 + Elec 8.9-kWh9.00 sec17.00 sec139 hpFWD
2017FE EcoHybrid Hatchback 1.6L I-4 + Elec 32-kW 1.56-kWh8.60 sec16.70 sec139 hpFWD

Service quick specs OEM factory data

Capacities, torques and tune-up values from the factory service manual.

Torque the oil drain plug to 25.0-32.0 ft-lbs.

Lubricants & capacities

Automatic Transmission FluidAPI · GL-4
Automatic Transmission Fluid Capacity1.79 qt

Engine torques

Intake Manifold to Engine Bolts14.0-17.0 ft-lbs
Exhaust Manifold to Cylinder Head Bolts26.0-30.0 ft-lbs
Engine Oil Pan Drain Plug25.0-32.0 ft-lbs

Ignition

Curb Idle Speed (No Load)Checking Speed: 630 rpm
Curb Idle Speed Variance (No Load)Checking Speed: 100 rpm
Curb Idle Speed (Secondary Under Load)Setting Speed: 700 rpm
Curb Idle Speed Variance (Secondary Under Load)Setting Speed: 100 rpm
Spark Plug ManufacturerKia
Spark Plug Gap0.028-0.031 in
Spark Plug Torque14.0-18.0 ft-lbs

Service checks

Regulated Fuel System Pressure (With Vacuum)70.0-75.0 psi
Regulated Fuel System Pressure (With Vacuum)Pressure must be > 42.0 psi

Brakes

Minimum Pad ThicknessFront: 0.354; Rear: 0.315

Multi-step torque procedures OEM · verified

Crankshaft Pulley and/or Damper Bolts — tightening sequence 1 stages
148.0-53.0 ft. lbs., Step 2: 39-41°48–53 ft. lbs
Cylinder Head — tightening sequence 1 stages
122.0 ft. lbs., Step 2: 90°, Step 3: 90°22 ft. lbs

Factory maintenance schedule OEM · verified

Normal service, condensed from the factory interval matrix.

Under the factory schedule, replace the spark plugs every 100,000 mi; coolant every 15,000 mi. The big-interval services (every 15,000 mi for coolant, and the transmission fluid) are the ones owners most often skip — on a lower-mileage example, assume the original fluids are still in it and check them first.

At 7,500 miClutch Master Cylinder (inspect fluid level)
Every 7,500 miAccessory Drive Belt (inspect) · Air Conditioning System (inspect) · Battery (inspect) · Brake Line (inspect) · Brake Linings (inspect) · Brake Rotor (inspect)
Every 15,000 miCabin Air Filter (replace) · Clutch Hydraulic System (drain & refill) · Clutch Master Cylinder (inspect fluid level) · Engine Coolant System (inspect fluid level) · Fuel Evaporative Canister Filter (inspect) · Fuel Evaporative Emission Control System Lines (inspect)
At 30,000 miEngine Coolant System (inspect fluid level)
Every 30,000 miFuel Line (inspect)
Every 37,500 miHybrid Inverter (drain, flush & refill coolant) · Transmission Assembly (inspect fluid level)
Every 60,000 miBrake Hydraulic System (drain, refill & bleed) · Drive Belt (replace)
Every 100,000 miSpark Plugs (replace)

Reliability & federal safety record

Owner-reported issues, recalls, investigations and service bulletins on record with NHTSA — an unfiltered look at what owners actually experience.

The 2021 Kia Niro recorded 9 complaints, 1 recall, 1 investigation, and 52 technical service bulletins (TSBs). Complaint volume rose sharply in 2022 to 27, peaked in 2023 at 40 complaints with 2 recalls, then fell to 8 complaints in 2024 before a modest increase to 13 complaints in 2025. Recall frequency remained relatively stable, ranging from 1 to 2 per year, while investigations were present only in 2021 and 2022. TSB activity was highest in 2021 and 2023 (52 and 50, respectively) and lower in the intervening and later years. Given that 2021 sits at the low‑complaint end of the observed trend and has a recall count comparable to most other years, it represents a comparatively favorable year to purchase a used Niro within this dataset.

1
Open recalls
NHTSA campaigns
52
Service bulletins
Manufacturer communications
1
ODI investigations
Office of Defects Investigation
9
Owner complaints
1 involved a crash · 0 a fire
Owner complaints by model year NHTSA · this generation & adjacent

Owner complaints filed with NHTSA, by component

All 9 complaints on record, top 8 components.

Unknown Or Other2
Power Train1
Power Train,Engine1
Vehicle Speed Control1
Power Train,Electrical System,Engine1
Electrical System1
Visibility1
Visibility/Wiper1

Source: NHTSA Office of Defects Investigation complaint database.

Recalls NHTSA · verified

Showing 1 of 1 campaigns on record for this vehicle.

23V534000Power Train:Automatic Transmission:Internal:Clutches/Bands:Actuators/SolenoidsReported 31/07/2023

Kia America, Inc. (Kia) is recalling certain 2017-2022 Niro and 2018-2022 Niro Plug-in Hybrid vehicles. Fluid may leak into the printed circuit board inside the hydraulic clutch actuator, which can result in an engine… Remedy: Dealers will inspect and replace the hydraulic clutch actuator as necessary and install a new fuse, free of charge. Owner notification letters were mailed December 29, 2023…

Technical service bulletins NHTSA · verified

Showing 5 of 52 bulletins on record with NHTSA.

BulletinDateComponentSummary
PI2603_TSB2026-06-15Electrical SystemTECHNICAL SERVICE BULLETIN: PRODUCT IMPROVEMENT CAMPAIGN: BMS BATTERY DIAGNOSTIC LOGIC…
TSB_ELE4222026-05-27Electrical SystemTECHNICAL SERVICE BULLETIN: INFOTAINMENT SYSTEM SOFTWARE UPDATE USING UPDATE.KIA.COM…
TSB_ELE4172026-04-14Electrical SystemTECHNICAL SERVICE BULLETIN: INFOTAINMENT SOFTWARE UPDATE PROCEDURE - This bulletin…
PS7972025-12-09Back Over PreventionPITSTOP: TECHNICAL OPERATIONS: EXTERNAL DAMAGE TO ULTRASONIC SENSOR: This Pitstop…
TSB_TRA046_R52025-04-17Power TrainTECHNICAL SERVICE BULLETIN: TRANSMISSION FLUID APPLICATION GUIDE - This bulletin has been…

Common OBD-II trouble codes

The most common OBD-II codes for this vehicle's emissions system. These are standardized SAE J2012 definitions, not vehicle-specific fault reports.

P0420
Catalyst system efficiency below threshold — Bank 1
P0300
Random / multiple cylinder misfire detected
P0171
System too lean — Bank 1
P0455
Evaporative emission system leak detected — large leak
P0128
Coolant thermostat below regulating temperature
P0442
Evaporative emission system leak detected — small leak

VIN tools

Decode factory build data for a specific vehicle by VIN.

VIN
Decode a VIN to confirm the transmission and build data for a specific Niro. OEM
Build data
Plant, GVWR class, engine and body data for any 17-character VIN.
Recalls
Check open recall campaigns against a specific vehicle by VIN.

Vehicles with shared specs

Find every vehicle that shares this one's battery, bulbs, oil capacity, platform or parts.

Reference guides

Cross-vehicle references for the kinds of data on this page.

Frequently asked

Does the 2021 Niro have open recalls?

NHTSA lists 1 recall campaign(s) for this model year. Check your specific vehicle by VIN.

What gas mileage does the Niro get?

EPA figures are 51 city / 46 highway / 49 combined mpg.