VOLUNTARY EMISSIONS SERVICE CAMPAIGN: THETA II 2.4L GDI EMISSIONS: ECM LOGIC IMPROVEMENT (SC340 REVISION 5) - 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 to upgrade the Electronic Control Module ‘ECM’ system software for certain 2016-2020MY Optima, 2016-2020MY Sorento, 2017-2022MY Sportage vehicles equipped with 2.4L Theta II engines listed in the table below. Kia has become aware that certain 2016-2022MY vehicles equipped with 2.4L Theta II engines may have engine calibrations that were not optimized for emissions standards under certain specific co
full bulletin at NHTSA ↗2021 Kia Sportage engine problems
severe 18 complaints filed with NHTSA · avg repair $3,100 · see engine across all vehicles →
Complaints
18
Recalls
0
Avg fix
$3,100
3fires
2injuries
When does it fail?
Of the 18 engine complaints filed for the 2021 Kia Sportage, here's the actual mileage breakdown — failures cluster heaviest at 100,000-125,000 mi.
0-25k
25-50k
50-75k
75-100k
100-125k
125-150k
150k+
Each bar shows the share of total complaints filed at that mileage range. Peak failure window highlighted. Some owners report problems earlier; some make it well past 150,000 miles symptom-free. Maintenance habits and driving conditions shift the curve as much as mileage alone.
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering engine 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.
VOLUNTARY EMISSIONS SERVICE CAMPAIGN: OWNER NOTIFICATION (SC340 FLIGHT 105) - This document is the owner notification advising that Kia is conducting a Voluntary Emissions Service Campaign to improve the emissions software logic in the Electronic Control Module (ECM) for certain 2017-2022 MY Sportage vehicles equipped with 2.4L Gas Direct Injection (GDI) engines to ensure compliance with emissions regulations.
full bulletin at NHTSA ↗TECHNICAL SERVICE BULLETIN: VOLUNTARY EMISSIONS SERVICE CAMPAIGN: THETA II 2.4L GDI EMISSION SECM LOGIC IMPROVEMENT (SC340 REV 4) - 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 to upgrade the Electronic Control Module ‘ECM’ system software for certain 2016-2022MY vehicles equipped with 2.4L Theta II engines listed in the table below. Kia has become aware that certain 2016-2022MY vehicles equipped with 2.4L Theta II engines may have engine calibrations that were not optimized for emissions standards under certain specific conditions. These calibrations
full bulletin at NHTSA ↗VOLUNTARY EMISSIONS SERVICE CAMPAIGN: OWNER NOTIFICATION (SC340 FLIGHT 103 / QL) - This document is the owner notification advising that Kia is conducting a Voluntary Emissions Service Campaign to improve the emissions software logic in the Electronic Control Module (ECM) for certain 2017-2022 MY Sportage vehicles equipped with 2.4L Gas Direct Injection (GDI) engines to ensure compliance with emissions regulations.
full bulletin at NHTSA ↗TECHNICAL SERVICE BULLETIN: VOLUNTARY EMISSIONS SERVICE CAMPAIGN: THETA II 2.4L GDI EMISSIONS ECM LOGIC IMPROVEMENT (SC340) - 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 to upgrade the Electronic Control Module ‘ECM’ system software for certain 2016-2022MY vehicles equipped with 2.4L Theta II engines listed in the table below. Kia has become aware that certain 2016-2022MY vehicles equipped with 2.4L Theta II engines may have engine calibrations that were not optimized for emissions standards under certain specific conditions. These calibrations may c
full bulletin at NHTSA ↗Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners of 2021 Kia Sportage vehicles describe four distinct engine problems. Most common is excessive oil consumption: owners add oil every 1,500–3,000 miles after an oil change, with dipsticks showing dry levels. No visible leaks appear underneath the car, and low-oil warning lights often fail to illuminate until damage is advanced. One owner burning oil since 80,000 miles faces a $10,000 engine replacement bill; Kia denies warranty coverage despite records showing regular maintenance and oil changes.
Loss of power strikes without warning: the check engine light flashes on abruptly, the engine refuses to accelerate above 40 mph, and the car stalls mid-drive. Diagnostic codes point to knock sensor or camshaft position issues; one owner pulled over on the highway when the engine lost power, creating a serious collision risk. Dealerships sometimes lack tools to diagnose or repair the problem.
Some owners report catastrophic internal failure: rod bearings grinding, crankshaft breaking, and engine block fragments appearing in the cradle cover. Finally, five narratives describe engine fires at low mileage (one at 19,920 miles), producing smoke and flames with zero warning lights beforehand. Two owners required medical attention for smoke inhalation. Warranty denials are common; Kia corporate has denied claims without detailed explanation, and owners allege the issue mirrors defects in earlier Theta II engines already under settlement.
Same Kia Sportage engine reports on nearby years: 2018 · 2019 · 2020 · 2022 · 2023
Failure modes owners describe
Excessive Engine Oil Consumption / Burning
Engine consumes or burns oil at abnormally high rates, requiring frequent oil top-offs between services. No visible oil leaks reported. Owners add oil regularly to prevent engine starvation.
When: Reported from 41,000 miles to 100,000+ miles; one owner began noticing the issue around 80,000 miles.
Symptoms owners cite: Oil level drops dramatically between services; Dry oil dipstick within 1,500–3,000 miles after oil change; No warning light illuminates in some cases; No visible oil leaks underneath vehicle
Repairs/costs cited: Engine replacement estimated at $10,000 (one owner). Some owners report continuing to add quarts manually to compensate.
Recalls/TSBs owners mention: Kia and dealers confirm no recalls or warranty campaigns available for 2021 Sportage VINs, despite similarity to Theta II engine settlement covering earlier model years.
Check Engine Light / Loss of Power
Engine fails to accelerate above 40 mph or loses motive power entirely while driving. Check engine light illuminates, sometimes flashing. Vehicle loses power suddenly with no prior warning.
When: Reported at 117,000 miles and other mileages; occurs without advance warning symptoms.
Symptoms owners cite: Check engine light illuminates or flashes; Vehicle cannot accelerate above 40 mph; Loss of motive power; unable to accelerate; Heavy steering may occur simultaneously; Vehicle stalls or shuts down
Codes mentioned: Knock sensor fault, Camshaft B position sensor fault
Repairs/costs cited: One dealership noted lack of software/special tools to repair timing components; vehicle required towing to Kia dealership. Some cases remain unrepaired.
Recalls/TSBs owners mention: Owner in one case was referred to NHTSA Campaign 25V099000 (Engine and Engine Cooling).
Catastrophic Engine Failure / Internal Component Failure
Engine experiences severe internal damage, including rod bearing failure, crankshaft failure, and metal fragments in oil. Engine block cracks or breaks apart while driving.
When: Reported at 100,000 miles and other mileages. One case occurred at approximately 70,000 miles.
Symptoms owners cite: Check engine light (sometimes flashing) and low oil light illuminate; Rod bearings grinding audibly; Metal particles found in oil during inspection; Engine shuts off while driving; Pieces of engine block found in cradle cover after failure
Codes mentioned: Engine warning lights, Low oil warning light
Repairs/costs cited: Complete engine failure; two owners reported finding engine block fragments. One owner required engine replacement; others did not pursue repair.
Engine Fire
Engine catches fire while vehicle is parked or stopped, producing smoke and flames from under the hood. Some fires occur at very low mileage with no warning.
When: Reported at approximately 19,920 miles and 70,000 miles. One fire started in drive-through of restaurant.
Symptoms owners cite: Strong burning odor detected; Smoke visible from underneath hood; No warning lights before fire started (in at least one case); Flames visible under hood; Vehicle burns to ground or becomes fully engulfed
Repairs/costs cited: Vehicles totaled. One owner required medical assistance for smoke inhalation (mother and grandmother). Fire department responded to at least two incidents.
Recalls/TSBs owners mention: One owner was awaiting callback from manufacturer after case was opened; another had not yet contacted manufacturer or dealer before fire consumed vehicle.
Synthesized from 18 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 8 most recent
I have experienced chronic and excessive engine oil consumption in my 2021 Kia Sportage S with the 2.4 L Theta II engine. Since around 80,000 miles, I have had to add oil every 2 weeks between oil changes to prevent the engine from running low. My vehicle now requires a complete engine replacement, estimated at $10,000. Despite regular maintenance and oil changes (documented by Express Oil…
My vehicle is burning oil. In a little over 1500 miles after I get a oil change from the King Kia Dealership Service, my oil stick shows that the level of oil in my engine is none at all. When I check my oil, the stick, is absolutely dry. This has happened in the last 3 oil changes with my vehicle. There is no oil indicator light that comes on in the dash, but the oil stick is dry. Additionally,…
The contact owns a 2021 Kia Sportage. The contact stated that her mother was driving at an undisclosed speed on the freeway and had stopped on the shoulder of the road to access the navigation system. The contact stated that after the driver shifted to park(P), the driver noticed smoke. The contact's grand-mother who was also occupying the vehicle advised the driver that the smoke was coming from…
The contact owns a 2021 Kia Sportage. The contact stated while driving at an undisclosed speed, the low oil light and engine warning lights illuminated. In addition, the contact stated that the vehicle had been consuming excessive engine oil. The vehicle was taken to an independent mechanic where it was diagnosed with a failed crankshaft and rocker arm. The contact was informed that the…
My car has been burning oil way too quickly! I got the 10,000 mile oil to see if it way maybe that and by 3,000 miles there was hardly any one in there! It is not leaking out! My oil is changed faithfully! And I heard there is a recall on some newer model Kia sportages! This is craziness! I take care of my vehicle stay up on all of the maintenance! I’ve read complaints on here and there are…
The contact owns a 2021 Kia Sportage. The contact stated that while his wife was driving at an undisclosed speed, the vehicle inadvertently lost motive power and was unable to accelerate. The contact's wife arrived at the destination where the failure persisted, prompting her to discontinue driving the vehicle. The check engine warning light was illuminated. The vehicle was not taken to the…
The contact owns a 2021 Kia Sportage. The vehicle was taken to an independent mechanic for an oil change, and the contact was advised that the oil level was low. The contact stated there was no warning illuminated with the oil level being low. The contact was advised by the mechanic to check the oil level more frequently. The contact had recently checked the oil level and needed to add one quart…
While I was driving in the interstate my car when in limp mode while I was trying to pass a semi. I had my children in the car and was stranded on the side of the road. No warning lights ever came on before hand. My mechanic said it was a problem with my engine and it’s common in Kia’s in but doe not include my year. It’s a costly repair for a car that’s not even 5 years old.
Had engine trouble with your 2021 Kia Sportage?
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 engine problem on the 2021 Kia Sportage?
It's a meaningful issue. 18 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $3,100.
At what mileage does the engine typically fail?
Based on the 18 complaints filed, engine issues most often appear around 69,584 miles. Some report problems earlier; some make it well past 150,000 with no symptoms. Maintenance habits matter — vehicles that received timely fluid services and were not regularly overworked tend to last longer.
What does it cost to fix?
Independent shops typically charge around $3,100 for engine 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 engine?
No active recalls currently cover engine 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/Sportage.
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.