This bulletin provides the procedure to update the TCU for shift shock when decelerating at slow speeds.
full bulletin at NHTSA ↗2018 Hyundai Sonata cruise control problems
severe Owners of the 2018 Hyundai Sonata have filed 11 NHTSA complaints about the cruise control at roughly $600 to repair (U.S. federal records, as of July 2026). Source: NHTSA Office of Defects Investigation. See cruise control across all vehicles →
Complaints
11
Recalls
0
Avg fix
$600
| Model year | cruise control complaints |
|---|---|
| 2014 Sonata | 14 |
| 2015 Sonata | 37 |
| 2016 Sonata | 15 |
| 2017 Sonata | 15 |
| 2018 Sonata (this page) | 11 |
| 2020 Sonata | 3 |
| 2022 Sonata | 7 |
5crashes
1injury
Is there a fix? Manufacturer service bulletins
The manufacturer has issued service bulletins covering cruise control 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.
Source: NHTSA manufacturer communications. Bring the bulletin number to your dealer or shop.
The failure pattern owners describe
Owners report unintended acceleration as the dominant problem—vehicle accelerating without pedal input, sometimes at low speeds when reversing or parking, sometimes at highway speeds. In multiple cases, brake application failed to stop the vehicle, resulting in crashes into poles, trees, walls, and barriers. Incidents occur across the mileage range from 500 to 41,000 miles.
Several owners describe the engine entering limp mode or protection mode, slashing power severely—sometimes to 2 mph crawl despite accelerator input. This typically coincides with check engine and tire pressure warning lights. Two owners mention engine stalling on the highway on separate occasions. One early complaint cited a rubber grommet stuck in the throttle body; Hyundai issued Service Campaign 953 (a software update) referenced in at least one narrative, though one owner worried about the safety implications of limp mode engaging without adequate warning.
One owner reports automatic emergency braking failing to stop the vehicle when another car is present, both in reverse and at highway speeds with cruise control active; the dealer dismissed it as normal.
A separate complaint describes prolonged cranking time (10–15 seconds) and jolting or stalling while driving. None of these issues have been consistently diagnosed or repaired across the narratives.
Same Hyundai Sonata cruise control reports on nearby years: 2015 · 2016 · 2017
Failure modes owners describe
Unintended acceleration / acceleration control malfunction
Vehicle accelerates without driver input or continues accelerating when brakes are applied. Occurs at low to highway speeds, sometimes immediately after brake release or when reversing. Brake pedal depression has failed to stop the vehicle in multiple incidents. Several crashes reported.
When: Various mileages: 500, 4000, 8800, 20000, 41000 miles; timing ranges from early ownership to several years in service
Symptoms owners cite: Vehicle accelerates without driver depressing accelerator; Brake pedal fails to slow or stop vehicle despite depression; Rapid forward acceleration when backing up or pulling from parking; Vehicle accelerates to 25 mph immediately after brake release; Accelerator unresponsive at traffic light, then accelerates to only 2 mph
Codes mentioned: P0638
Repairs/costs cited: Narrative #1: rubber grommet found stuck in throttle body; removed during throttle body carbon cleaning. Narrative #3: dealer did not provide work order; vehicle not repaired after second occurrence. Narrative #4: loose cable identified (type unspecified); vehicle not repaired, traded in. Narrative #7: dealer unable to duplicate; not diagnosed or repaired. Narratives #9, #10: not diagnosed or repaired.
Recalls/TSBs owners mention: Narrative #2: Hyundai Service Campaign 953 (software update) referenced but not yet performed at time of complaint. Narrative #4: manufacturer notified. Narrative #6: manufacturer notified but no assistance offered. Narrative #7: manufacturer notified, case open.
Limp mode / engine protection mode activation with reduced power
Engine enters limp or fail-safe mode, cutting power and acceleration severely, sometimes without warning. Vehicle unable to maintain speed or accelerate. Occurs concurrently with check engine and tire pressure warning lights.
When: Early ownership (days to weeks); at least two instances on highway; one at 4000 miles
Symptoms owners cite: Check engine light illuminates; Tire pressure monitoring system warning lights; Tire control stabilizer warning; Vehicle shaking and losing speed; Brakes become hard; power steering becomes heavy; Engine enters protection mode with severely reduced power and acceleration; Vehicle crawls at 2 mph or less despite accelerator input; Engine stalls on highway on two separate occasions
Codes mentioned: P0638, P211935002A00
Repairs/costs cited: Narrative #1: rubber grommet removed from throttle body; issue resolved after removal. Narrative #8: first incident attributed to glitch in software update performed months prior; second incident cause unknown per dealer.
Recalls/TSBs owners mention: Narrative #2: Service Campaign 953 software update referenced. Narrative #8: software update performed prior to stalling incidents.
Automatic emergency braking system malfunction
AEB system fails to engage when a second vehicle is present. Failure occurs in reverse and at highway speeds with cruise control active. Dealer dismissed malfunction as normal operation.
When: 400 miles
Symptoms owners cite: Vehicle fails to automatically stop when second vehicle present in reverse; Vehicle fails to automatically stop when second vehicle present at highway speeds with cruise control active; AEB does not function despite being activated
Recalls/TSBs owners mention: Dealer stated failure was normal. Manufacturer notified but offered no assistance.
Prolonged engine start time and loss of power while driving
Engine requires extended button press (10-15 seconds) to start. Vehicle jolts or attempts to stall while driving. Symptoms suggest intermittent power loss or engine control issue.
When: Ongoing since week of 9/5/22
Symptoms owners cite: Engine takes 10-15 seconds of pushing start button to crank; Vehicle jolts or wants to stall while driving; Intermittent loss of motor power
Synthesized from 11 NHTSA owner complaints — unverified consumer allegations, summarized for patterns. The verbatim filings appear below.
What owners are reporting 0 most recent
Had cruise control trouble with your 2018 Hyundai Sonata?
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 cruise control problem on the 2018 Hyundai Sonata?
It's a meaningful issue. 11 complaints have been filed and the failure mode causes operational problems for owners. Repairs average $600.
At what mileage does the cruise control typically fail?
Based on the 11 complaints filed, cruise control issues most often appear around 15,729 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 $600 for cruise control 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 cruise control?
No active recalls currently cover cruise control 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/Hyundai/Sonata.
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.