Tl* the contact owns a 2018 Kia soul. While the accelerator pedal was depressed, the vehicle jerked, lost power, and the power assist warning indicator illuminated. When the contact turned off and restarted the vehicle, it resumed normal operation. The vehicle was taken to weseloh Kia carlsbad (5331 paseo del norte, carlsbad, ca 92008, (760) 208-2237) to be diagnosed, but the cause of the failure…
2018 Kia Soul powertrain problems
moderate 29 complaints filed with NHTSA · avg repair $2,500 · see powertrain across all vehicles →
Failure mileage
Complaints
29
Recalls
0
Avg fix
$2,500
What stands out
Owners have filed 29 powertrain 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.
No new NHTSA powertrain complaint has been filed on this vehicle in over 6 years — the issue may be aging out of the active population.
The failure pattern owners describe
Buyer takeaway: A used 2018 Kia Soul can develop severe powertrain issues—engine knock, sudden loss of power, transmission hesitation, and recurring check engine lights—that dealers struggle to diagnose and fix permanently. These problems show up across all mileages and may not be covered by warranty even if a recall notice wasn't properly delivered to the owner.
Owners of 2018 Kia Souls describe a troubling pattern of intermittent power loss, hesitation, and stalling that dealers cannot reliably fix. Loss of acceleration happens unpredictably—sometimes at highway speed, sometimes from a stop—leaving drivers unable to maintain safe traffic flow. Check engine lights come on repeatedly; dealers reset them only to have them return within weeks. One owner was told to keep driving until the light came back on, despite the car losing power on the highway.
Engine knock is a recurring complaint. Owners report rod knock at 65,000 to 100,000+ miles; a local mechanic cited $4,000–$5,000 for engine bottom-end replacement. Kia has issued recalls for similar engine issues in earlier model years (2011–2016) but not for the 2018. When owners call Kia customer service, they're told their VIN isn't covered or they're out of warranty, even if they never received notification of required software updates.
Transmission issues include hesitation from stops and jerking during acceleration, which owners describe as unpredictable and safety-hazardous. Multiple transmission replacements have failed to resolve the problem in at least one case. Oil leaks and sludge accumulation, combined with poor diagnosis by dealers, have led to $5,400+ catalytic converter failures and full engine replacement quotes of $9,000–$11,000.
Throughout these complaints, dealers either cannot find the problem, cannot replicate it, or decline to repair under warranty citing missing recalls or software updates the owner was never notified of receiving.
Same Kia Soul powertrain reports on nearby years: 2015 · 2016 · 2017 · 2020 · 2021
Failure modes owners describe
Sudden loss of power / stalling while driving
Engine loses power unexpectedly while driving at highway speeds or in traffic, sometimes with warning lights (transmission temp high, check engine), sometimes without. Vehicle may refuse to accelerate when gas pedal is pressed or engine may stall completely. Often recurs even after dealer service.
When: Occurs unpredictably throughout vehicle life; some complaints from early ownership (340 miles, 16,000 miles) to high mileage (77,000+ miles)
Symptoms owners cite: Loss of acceleration when pressing gas pedal; Engine stall without warning; Vehicle slows down unexpectedly on highway; Hesitation from stop sign or traffic light; Check engine light illumination; Transmission temp high warning message; Limp mode limiting RPMs to 1800-2000
Codes mentioned: P1326, P0507
Repairs/costs cited: Multiple repair attempts by dealers with no resolution; some owners report transmission replacement (twice in one case), knock sensor replacement, software updates (KSDS), engine replacement denied by manufacturer in at least one case. Alternator replacement failed to resolve issue long-term.
Recalls/TSBs owners mention: Product Improvement Campaign letter sent November 2021 for Knock Sensor Detection System (KSDS) software update; however, owners report system still enters limp mode after update. Kia refused warranty coverage in at least one case when owner did not receive recall notice. Case numbers issued but no further assistance provided. One owner told by Kia customer service that engine replacement would not be approved despite warranty coverage due to no recall being issued yet for 2018 model year.
Engine knock / rod knock / catastrophic engine failure
Abnormal knocking or rod knock sound from engine, often progressing to complete engine failure with metal damage to cylinders, rings, and valves. Occurs at various mileages. Check engine light may or may not illuminate. Some cases accompanied by oil sludge or burning smell.
When: Reported at mileages ranging from 65,000 to 100,000+ miles; one case at 78,388 miles, another at 80,000 miles, another at 86,000 miles
Symptoms owners cite: Abnormal knocking noise from engine; Grayish smoke from engine; Burning smell (especially when A/C on); Oil light flickering; Complete engine failure; Loss of power accompanied by knock; No warning light in some cases
Repairs/costs cited: Local mechanics cited repair cost of $4,000–$5,000 for engine bottom-end replacement (rods). Dealership quoted $9,000–$11,000 for full engine replacement. One owner reports oil sludge inside engine requiring complete replacement.
Recalls/TSBs owners mention: No recalls issued for 2018 model year despite similar issues reported in earlier model years (2011–2016 Theta, Nu, Gamma engines). Kia customer service refused warranty coverage in at least one case citing engine failure despite vehicle mileage. One dealer offered warranty coverage when vehicle had not received software update; vehicle not repaired due to recall eligibility question.
Transmission hesitation, jerking, and sluggish acceleration
Transmission hesitates or jerks during acceleration, especially from a stop. Vehicle may feel sluggish or stumble unpredictably. Problem occurs intermittently and may recur after dealer service. In some cases, transmission may not respond at all when accelerator is pressed.
When: From early ownership (5,600 miles at purchase) through normal operation; one case with 36,269 miles when transmission replacement was attempted
Symptoms owners cite: Hesitation from stop or red light; Sluggish acceleration or stumbling; Hard jerk when transmission finally engages; Accelerator pedal pressed to floor with no response; Vehicle moves in wrong direction (forward instead of reverse); Unpredictable drivability
Repairs/costs cited: Clutch actuator replaced in one case; transmission replaced twice in another case with no resolution. Dealer statement: 'Dealer stated that the vehicle performed as designed' and cleaned turbo; transmission also had internal mechanical damage in at least one case. One owner paid for new transmission under warranty after multiple visits.
Recalls/TSBs owners mention: Kia and dealers attributed hesitation to 'normal for the new transmission/turbo design' in at least one case. No TSB (Technical Service Bulletin) opened yet for P1326 code on 2018 model year at time of repair attempt (January 2022).
Oil leakage and oil sludge
Oil leaks internally or externally, leading to oil light illumination after oil changes. Engine sludge accumulation occurs. In one case, oil leaked into catalytic converter and caused converter failure.
When: Starting December 2021 in one case; used vehicle purchased January 2021 in another case with oil issues appearing by late January
Symptoms owners cite: Oil light coming on after oil change; Low oil warning despite recent oil change; Engine sludge visible upon inspection; Oil pressure light illumination; Oil leaking to catalytic converter
Repairs/costs cited: Oil consumption tests performed with no findings per dealer; oil gasket replaced in one case; catalytic converter replacement quoted at $5,400 by dealership. Oil sludge in engine detected during later diagnostic requiring full engine replacement.
Recalls/TSBs owners mention: Dealer reported 'nothing wrong with the vehicle' despite repeated complaints and oil consumption testing. No recalls mentioned by Kia for oil-related issues.
Accelerator pedal unresponsiveness and loss of power assist
Accelerator pedal does not respond when pressed or travels to floor with no engine response. Loss of power assist warning indicator may illuminate. Problem is intermittent and may resolve after vehicle restart.
When: One case at approximately 100 miles; recurring multiple times
Symptoms owners cite: Accelerator pedal depressed with no response; Accelerator pedal travels to floorboard without effect; Power assist warning indicator illuminated; Engine jerks and loses power when accelerator pressed; Problem resolves after vehicle shutdown and restart
Repairs/costs cited: Clutch system was slipping and replaced; dealership would not replace transmission per owner statement
Recalls/TSBs owners mention: Manufacturer made aware but informed contact that VIN was not included in recall; provided case number but no further assistance
Check engine light with repeated illumination and inability to diagnose
Check engine light comes on repeatedly and does not stay off. Dealers unable to diagnose or repair underlying cause. Owners instructed to drive vehicle until light comes back on despite safety concerns. Problem recurs within weeks of dealer service.
When: Ongoing issue; one complaint notes over one year of recurrence; another after software update (December 2021)
Symptoms owners cite: Check engine light illumination; Blinking check engine light (after KSDS software update); No specific drivability complaint associated in some cases; Light returns after dealer repair attempt
Codes mentioned: P1326, P0507
Repairs/costs cited: Dealers unable to identify cause; one owner instructed to drive vehicle and return when light illuminates again despite power loss issue. MAP sensor and throttle body relearning attempted in one case; software updates applied in others.
Recalls/TSBs owners mention: No TSB opened for P1326 on 2018 model year as of January 2022. Knock Sensor Detection System software update (November 2021 campaign) resulted in limp mode activation in at least one case.
Stalling and steering power loss while turning
Vehicle stalls while making a turn at low speed (approximately 35 mph) and power steering is lost simultaneously. No warning lights illuminate. Problem recurs multiple times.
When: At approximately 11,000 miles
Symptoms owners cite: Vehicle stalling while turning; Loss of power steering; No warning indicator illuminated
Repairs/costs cited: Technician unable to duplicate failure; vehicle not repaired
Recalls/TSBs owners mention: Manufacturer referred contact to Consumer Support Acceleration Team; case number issued but dealer stated they could not assist
Brake failure and transmission control malfunction
Brake pedal does not respond when pressed to floor. Transmission does not respond to gear selection (Reverse does not engage; Drive remains active). Problems occur on same occasion and may resolve after vehicle restart.
When: Early in vehicle ownership (September 2019); at approximately 340 miles in another case
Symptoms owners cite: Brake pedal pressed to floor with no response; Transmission shifts to wrong gear (Forward instead of Reverse) or does not shift; Inability to shift out of Drive to Neutral or Park; Problems resolve after vehicle restart
Repairs/costs cited: Dealer found no issues during diagnostic testing; vehicle continued to be tested
Recalls/TSBs owners mention: No response mentioned in narrative
Synthesized from 29 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 2 most recent
Description of the Problem: My 2018 Kia Soul has a recurring and unresolved safety issue involving sudden loss of power while driving. The check-engine light repeatedly comes on, and at times the vehicle will hesitate or lose acceleration unexpectedly, creating a risk of being unable to maintain speed in traffic. Chronology: This issue has been occurring for over a year. I have taken the vehicle…
Had powertrain trouble with your 2018 Kia Soul?
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 2018 Kia Soul?
It's a documented issue but not catastrophic. 29 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?
Across the 9 complaints that reported odometer mileage, most powertrain failures cluster between 11,000 and 54,000 miles, with the median around 33,000. A quarter of owners report trouble before 11,000; a quarter make it past 54,000. 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 $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/2018/Kia/Soul.
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.