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 ↗2018 Kia Sportage engine problems
severe Owners of the 2018 Kia Sportage have filed 65 NHTSA complaints about the engine, typically surfacing around 60,000 miles at roughly $3,100 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See engine across all vehicles →
Failure mileage
Complaints
65
Recalls
0
Avg fix
$3,100
| Model year | engine complaints |
|---|---|
| 2014 Sportage | 58 |
| 2015 Sportage | 58 |
| 2016 Sportage | 41 |
| 2017 Sportage | 153 |
| 2018 Sportage (this page) | 65 |
| 2019 Sportage | 22 |
| 2020 Sportage | 65 |
| 2021 Sportage | 19 |
| 2022 Sportage | 15 |
7fires
1injury
When does it fail?
Of the 65 engine complaints filed for the 2018 Kia Sportage, here's the actual mileage breakdown — failures cluster heaviest at 50,000-75,000 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.
What stands out
Engine accounts for 41% of every owner complaint on file for this vehicle — the dominant problem area across 9 categories tracked.
Owners have filed 65 engine complaints with NHTSA against this vehicle, but no formal recall covers the issue — the federal record reflects what manufacturers have admitted, not everything owners are reporting.
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
The 2018 Kia Sportage 2.4L engines in these 61 complaints show a consistent pattern of severe failures. The most common issue is excessive oil consumption—owners report burning a quart per 1,000 miles or more, forcing weekly oil top-ups. This leads directly to low oil pressure warnings, check engine lights, and catastrophic internal damage.
Owners describe piston ring wear, fouled pistons, misfire in one or more cylinders, and connecting rod bearing failure. Diagnostic codes P1326 (Knock Sensor Detection System, often linked to bearing wear), P0010 (camshaft issues), P0303, and P0200A appear repeatedly. When owners take vehicles in for diagnosis, dealers confirm burned pistons, zero compression in affected cylinders, holes in pistons, and metal shavings in the oil.
The failures occur across a wide mileage range—from 18,000 to 150,000 miles—but cluster heavily between 60,000 and 130,000. Several owners report engine fires or near-fires during normal highway driving. Others describe sudden limp mode, loss of power, stalling without warning, and complete engine seizure. Some vehicles require full long-block replacement; some owners report needing a second replacement shortly after the first.
Owners consistently mention Kia's Knock Sensor Detection System software update (Campaign SC200) and oil consumption testing protocols, but report that dealers often deny warranty claims, defer repair pending further testing, or advise trading in the vehicle. Many cite class action settlements and previous recalls for similar engines in other Kia/Hyundai models, noting their VINs did not qualify despite identical symptoms.
Same Kia Sportage engine reports on nearby years: 2015 · 2016 · 2017 · 2019 · 2020
Failure modes owners describe
Excessive oil consumption leading to low oil pressure and engine damage
Engine burns or consumes oil at rates exceeding manufacturer specification (often 1+ quart per 1,000 miles), causing oil starvation, low oil pressure warnings, and accelerated wear on internal components.
When: Occurs across wide mileage range; many reports between 40,000–120,000 miles, some as early as 18,000–20,000 miles
Symptoms owners cite: Low oil level despite no visible leaks; Oil warning light illumination; Oil light coming on between scheduled oil change intervals; Requirement to add 5–7 quarts of oil between changes; Burning oil smell; Check engine light
Codes mentioned: P0303, P0010, P0200A, P1326
Repairs/costs cited: Owners report dealership oil consumption testing (1,000-mile interval tests over 3 cycles); some dealers recommend full long-block engine replacement costing $4,800–$12,500; others deny warranty claims citing lack of service history or dispute normal consumption levels
Recalls/TSBs owners mention: Kia Technical Service Bulletin 222 outlines oil consumption diagnostics; some owners mention Knock Sensor Detection System software update (Campaign SC200); owners report dealers often deny claims based on VIN not matching settlement eligibility or citing lack of historical maintenance records
Piston ring wear and fouled pistons causing misfire and compression loss
Piston rings wear prematurely or foul, reducing compression and causing single or multiple cylinder misfire. Owners report mechanics finding holes in pistons, zero compression in affected cylinders, and metal shavings in oil.
When: Reports from 55,000 to 139,000 miles; some early reports near 20,000 miles
Symptoms owners cite: Check engine light; Engine hesitation or misfiring; Rough idle; Engine making truck-like noise on startup; Loss of power under acceleration; Shaking or shuddering while driving; Dipstick showing extremely low or dry oil levels
Codes mentioned: P0303, P0010, P1326
Repairs/costs cited: Mechanics confirm worn piston rings via compression testing (0 psi in affected cylinder) and visual inspection; long-block engine replacement required; some owners report receiving rebuilt engines rather than new units; one owner reports needing two engine replacements within months of each other
Recalls/TSBs owners mention: Kia denies warranty coverage in many cases; some owners report being advised to trade vehicle in or told engine seizure must occur before replacement is approved; settlement eligibility denials cited despite matching vehicle criteria
Connecting rod bearing failure detected by Knock Sensor Detection System
Excessive connecting rod bearing wear triggers P1326 code and KSDS warning, forcing vehicle into limp mode to prevent catastrophic engine seizure.
When: Reports from 111,595 to 150,000 miles
Symptoms owners cite: KSDS (Knock Sensor Detection System) warning light illumination; Check engine light (flashing in some cases); Vehicle entering limp mode or reduced-power mode; RPM and speed limiting; Knocking noise from engine; Sudden loss of power while accelerating
Codes mentioned: P1326
Repairs/costs cited: P1326 code specifically indicates excessive bearing wear detected by knock sensor; owners report dealerships stating no current recall or campaign applies; some have received knock sensor software updates (Campaign SC200) prior to failure; bearing failure requires long-block replacement
Recalls/TSBs owners mention: Campaign SC200 (Knock Sensor Detection System software update) installed on some vehicles; owners report settlement VIN-check websites incorrectly rejecting their vehicles despite meeting criteria; Kia denies lifetime short-block warranty in disputed cases
Sudden engine failure, stalling, and seizure while driving
Engine stops abruptly during highway or city driving, sometimes with minimal warning, leaving vehicle disabled and posing collision risk.
When: Various mileages; some reports as low as 18,000–20,000 miles; others at 55,000, 86,000, 117,000+ miles
Symptoms owners cite: Sudden engine shutdown or stalling; Loss of motive power while driving; Check engine light (sometimes flashing immediately before stall); Low oil warning light; Engine knocking or clicking noise; Smoke from engine compartment; Inability to restart or severe power limitation after restart
Repairs/costs cited: Mechanics and dealers diagnose engine failure; metal shavings found in oil indicate bearing or internal damage; long-block replacement required; some owners report 6-month waits for engine availability; engine seizure occurs with no warning in some cases
Recalls/TSBs owners mention: Limited manufacturer response documented; some owners report cases opened at dealership level but inspections pending; manufacturers reportedly advise case closure pending legal resolution
Engine fire while driving or parked
Fire develops in engine compartment during normal driving or immediately after shutdown, requiring emergency evacuation and fire department response.
When: Reported at 55,000 and 60,000 miles
Symptoms owners cite: Black smoke billowing from engine compartment; Grey smoke under hood; Burning smell; Explosion sound from engine compartment; Flames engulfing front of vehicle
Repairs/costs cited: Vehicles declared total loss by insurance; towed to salvage yards; one owner suffered sprained ankle while evacuating; another owner sought medical treatment for cardiovascular symptoms after incident
Recalls/TSBs owners mention: One complaint mentions NHTSA Campaign 21V137000 (Service Brakes, Hydraulic) and 18V907000 (Fuel System), but vehicles were not covered by these campaigns; manufacturer inspection pending in at least one case
Camshaft failure and valve train issues
Camshaft failure or improper valve operation causing acceleration problems and check engine codes.
When: Reported at approximately 150,000 miles
Symptoms owners cite: Failure to accelerate as intended; KSDS warning light; Check engine light; Abnormal oil consumption
Codes mentioned: P0010
Repairs/costs cited: Dealer diagnosed and recommended camshaft replacement; repair completed at owner's expense
Recalls/TSBs owners mention: Manufacturer notified; case filed
Improper fuel/air mixture and intake valve issues
Fuel/air mixture problems and intake-related malfunctions causing rough running on brand-new vehicles and during early ownership.
When: Reported at 34 miles (new vehicle) and early in ownership
Symptoms owners cite: Hesitant driving or misfiring sensation; Check engine light; Truck-like sound on startup
Codes mentioned: P0303
Repairs/costs cited: Brand-new vehicle developed check engine code P0303 (Multiple Cylinder Misfire) after 34 miles; diagnosis pointed to improper fuel/air mixture in cylinder 2
Recalls/TSBs owners mention: Customer service advised dealership visit; initial dealership diagnosis performed but outcome not specified
Unreliable engine control electronics and sensor system
Knock Sensor Detection System, engine control software, and related electronics produce inconsistent warnings, fail to prevent bearing failure, or generate repeated false codes.
When: Throughout ownership; some issues emerge after ECU software updates
Symptoms owners cite: P1326 code persistent after knock sensor replacement; Random engine revving without driver input; Dashboard and radio randomly flashing; Loss of power after ECU/software upgrade
Codes mentioned: P1326
Repairs/costs cited: One owner reports P1326 recurring after knock sensor was replaced; owners note that Knock Sensor Detection System software updates (Campaign SC200) did not prevent subsequent bearing failures; one owner reports severe loss of power less than 9,000 miles after ECU upgrade
Recalls/TSBs owners mention: Campaign SC200 (Knock Sensor Detection System software update) implemented; owners report it provides detection of bearing failure but does not prevent it
Synthesized from 65 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 11 most recent
We own a 2018 Kia Sportage. We never had any problems with it, UNTIL NOW. I Drove it to work one morning, and was on the way home and suddenly without warning, no lights, or indicators came on, and the car started to shake, and lost full throttle response in the MIDDLE OF TRAFFIC. Immediately pulled over! Tried starting the car again, but the car was not cranking. We had to tow our car home, and…
Car shifts to low mode from 50-20mph on its own slow deceleration when stopping slow acceleration when stationary
The contact owns a 2018 Kia Sportage. The contact stated that while driving at an undisclosed speed after an oil change was recently performed on the vehicle, the low oil pressure warning light illuminated with the message "Service Engine" displayed, and the vehicle made a dinging sound. The vehicle was taken to the dealer, where 5 quarts of oil were added to the engine; however, the failure…
My 2018 Kia Sportage (2.4L Theta II GDI engine) suddenly triggered diagnostic trouble code P1326 (Knock Sensor Detection System – Detection of Excessive Connecting Rod Bearing Wear) and entered limp mode at 111,595 miles on Sep 13, 2025. The vehicle is now speed- and RPM-limited to protect the engine from catastrophic failure. This is the exact failure mode covered under the well-documented…
The RPM randomly goes up and down frequently. When I took it in to the dealer they test drove it and said didn’t do it and blew me off.
The contact owned a 2018 Kia Sportage. The contact stated that while driving at an undisclosed speed, he observed black smoke billowing from the engine compartment, after which the vehicle lost motive power, prompting him and his wife to evacuate the vehicle in the middle of the roadway. While attempting to retrieve important belongings from the vehicle, the contact stated that he heard what…
Vehicle engine accelerated and raced without warning with foot on brake. Has occurred on several occasions with different household operators. Vehicle has about 18,000 miles.
The contact owns a 2018 Kia Sportage. The contact received notifications of NHTSA Campaign Number: 22V703000 (Trailer Hitches) and 21V137000 (Service Brakes, Hydraulic); however, the contact was possibly charged for the recall repairs. The contact stated that while driving at various speeds, the vehicle failed to accelerate as intended while depressing the accelerator pedal. The KSDS warning…
The contact owns a 2018 Kia Sportage. The contact stated that while driving 10 MPH, the vehicle was jerking and hesitating while driving. The contact stated that several unknown warning lights were illuminated. The vehicle was towed to the residence and then towed to the dealer to be diagnosed. The contact was informed that the engine had failed and needed to be repaired. The vehicle was…
Due to excessive oil consumption and blow thru to catalytic converter, and burning of oil in the converter clogged up my catalytic converter as seen in pics causing exhaust fumes to enter cabin and engine not run properly. Driver or passenger must open windows to get fresh air. I had to have converter replaced. There is still periodic fumes that enter cabin even with new converter because engine…
Had engine trouble with your 2018 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 2018 Kia Sportage?
It's a meaningful issue. 65 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?
Across the 18 complaints that reported odometer mileage, most engine failures cluster between 13,000 and 100,000 miles, with the median around 60,000. A quarter of owners report trouble before 13,000; a quarter make it past 100,000. Maintenance history matters more than the odometer alone — this is the reported failure window, not a guarantee.
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/2018/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.