2018 Hyundai Sonata: Check engine light on
Common wear/failure (not a recall)
Symptoms
Owners of the 2018 Sonata report: check engine light on. CarComplaints.com lists 12 owner complaints, average mileage 22,600 miles.
NHTSA has 224 owner complaints for the 2018 Sonata in this area. Examples:
- NHTSA complaint ODI #11769166 (filed 10/05/2026): “What component or system failed or malfunctioned, and is it available for inspection upon request? the paint is peeling off the car, when i went to the dealership they said this is a known problem for 2015-2018, but they can't fix it there is no recall. it is …”
- NHTSA complaint ODI #11765780 (filed 09/21/2026): “Hyundai dealership confirms i am in need of a new engine due to large oil consumption which is a known issue on 2018 hyundai sonata engines. hyundai will not approve repairs because i am the second owner and vehicle is out of the 5 year warranty period. i only…”
Likely causes
Sources do not establish a single root cause; diagnosis is needed. Owner-reported fixes are listed below.
Fix, in plain English
Most common owner-reported solutions on CarComplaints.com: replace wire harness (5 reports) fixed, after three of little to no communication (1 reports). Check for open recalls and extended warranty coverage with a dealer before paying out of pocket.
DIY difficulty: Pro
Internal engine work (lifters, oil consumption, fuel dilution diagnosis) requires engine teardown or dealer software/tests. (Our assessment.)
Cost
CarComplaints.com owners report a typical repair cost of about $1,310 (owner-reported average, not a quote).
Typical parts (search links, no affiliate codes)
AutoZone · O'Reilly · Advance · RockAuto
Sources
Page last updated .