2018 Hyundai Sonata Electrical System Problems

We think there’s an issue with the abs module and wheel speed sensor because we started having a problem where the brakes wouldn’t work or would stutter. The car would shake real bad it would make an awful grinding sound but normally only when trying to stop at higher speeds or long braking. The only thing that made it stop was to unplug the abs but then other parts of the car stopped working like the speedometer and the sensors around the car. So we got the abs replaced but the new one started doing the same thing. We did some research and it sounds like the same issue Hyundai is having with the palisade. The incident that made us get it replaced to begin with was were driving down the road and we got to a traffic light but when we tried to brake they just didn’t work so we drove through the red light luckily the one person who was supposed to be going saw us and didn’t pull out in front of us so we didn’t get hit. We haven’t taken it to the dealership yet but my sister who teaches automotive repair at the community college is the one who diagnosed it so she said we should report it here so maybe it won’t happen to anyone else. Before we had the brake issue we were having problems with basically everything on the dash not working randomly. We’d be driving down the road and the speedometer and the outside sensors and the gas gauge and the traction control all would go out at the same time it’s the same stuff that went out when we had the abs unplugged so it seems that might be related.

Unknown. 2018 Hyundai Sonata engine has failed. Only purchased the vehicle in December 2024, and the engine is defective. There is much information, via research, indicating that Hyundai is aware of the engine issues with this year vehicle, but are unwilling to make amends. Vehicle has 100,189 miles.

Odometer Fraud. The contact purchased a 2018 Hyundai Sonata. The contact discovered a mileage discrepancy while searching the vehicle history report. The contact stated that the odometer indicated several readings. The vehicle was a dealer sale. The contact was unaware that at the time of purchase, the vehicle mileage was 148,000. The contact stated that the mileage on the Title was blank, and the mileage on the registration was 75,519.

car turned off at light all lights work and turns on engine won’t roll over the battery and alternator and starter are all good

I first noticed that my vehicle was consuming an excessive amount of motor oil, with the oil change light coming on every 1,500–2,000 miles. I routinely had to add oil between changes to keep it running. On May 30th, while driving on surface roads, I heard clanking noises from the engine. When accelerating, the vehicle clanked heavily, and then went into “limp mode,” limiting acceleration to about 10 MPH before struggling up to 30 MPH. I added oil, but a local shop diagnosed it with code P1326 (knock sensor) and advised that Hyundai engines are prone to failure around 100,000 miles and that I should take it to the dealer for warranty evaluation. I contacted Graham Hyundai, who told me they could not see the vehicle until July 1st and that I would be responsible for towing. I dropped the vehicle off on July 1st, but it was not inspected until July 8th or 9th. I was later told Hyundai was being consulted. Around July 15th–16th, the dealership informed me that I would need $1,500 in repairs. They stated the engine had passed the Hyundai Bearing Clearance Test (a $350 charge) and that Hyundai required me to pay for an ECU “KSD logic” upgrade ($175). They also stated the engine valve cover was leaking, requiring new spark plugs, for a total of $532. Additional charges included an oil change and other shop fees and taxes. After repairs, I was instructed to drive 1,000 miles and then return for an oil consumption test. After approximately 1,000 miles and four weeks, the dipstick check showed the vehicle had consumed nearly all of its oil. I was then told I now need a combustion chamber cleaning, costing approximately $850 and requiring three days in the shop. Given the oil consumption issues, repeated engine warnings, limp mode incident, and the significant costs already incurred for testing and required upgrades, I am requesting that my engine be replaced under warranty and that all fees I have already paid be reimbursed. Rather than keep paying for work.

The contact owned a 2018 Hyundai Sonata. The contact stated that upon her daughter reaching her destination, she observed brown smoke emanating from the engine compartment. Within a short while, the vehicle became completely engulfed in flames, prompting a bystander to attempt to extinguish the fire with a fire extinguisher, but was unsuccessful. Local emergency services arrived and were able to extinguish the flames. A fire report was filed, and it was indicated that the fire may have been electrical, but an exact cause had not been determined. A police report was filed, and no injuries were reported. The vehicle was towed to a tow yard and deemed a total loss by the contact's insurance provider. The manufacturer was not notified of the failure. The failure mileage was 125,000.

Oil consumption was ridiculously high, changing oil/topping off oil constantly. Car would not accelerate over 30 mph without sputtering and rumbling. I had mechanic diagnose bad sparks plugs due to sitting in oil from leaking. After I had them repaired/replaced the car drove great for 1 day, then decided to die in the middle of a busy intersection while I had my teenage son in the car with me. My son and I had to PUSH it out of the busy intersection onto a side street to get out of the way! I had it towed to Hyundai dealer who said the spark plugs were bad and that the fuel pressure sensor and gdi pump were faulty and needed replacement. Left front lower control arm/ball joint assembly also requires fix. To the tune of $3000 + . It’s been at dealer for past few months until I can afford the repairs including the 2nd diagnostic and tow it took to get it to dealership.

43000 miles on car. original owner. new battery. car does not cold start in the morning. all electronics light up, but engine doesn't start. This is a known issue from all the posts i found online, yet Hyundai has not issued a recall. I paid 300 for a battery 2 weeks ago and the issue didn't resolve. Now i am being told by dealer it is the starter and it's not covered because my 5 yr warranty is expired (my car is 6 years old). This is a known safety issue across the 2018 Sonata line. This should be a recall or bulletin, instead I have to come up with hundreds of dollars more to replace a starter on a car with ONLY 43,000 miles.

The electrical and engines in these cars are horrible . The steering wheel keeps locking up while driving cause everything to flick inside the car . This is a major safety issue for me when I am driving and I am unable to control the steering wheel. Dealership claimed they don’t see the issue with the car which I am stating . The vehicle was only inspected by a mechanic and since Hyundai said they couldn’t find anything a 3rd party confirmed that this was a ongoing issue and dealership could’ve caught it but it’s cheaper the sell the car . No everything happens at once especially if I’m turning or driving under 40 mph. First appeared 15 days after I bought the vehicle I alerted the dealership immediately

To Whom It May Concern, My name is [XXX] , and I am formally escalating serious ongoing issues with my 2018 Hyundai Sonata. Despite repeated attempts to resolve these concerns through the dealership, my vehicle continues to experience excessive oil consumption, engine failures, and additional mechanical issues, all while under warranty. I am now seeking immediate corporate intervention. Timeline of Events and Mismanagement: •2024(~62000 miles): First reported oil leak and excessive oil consumption. Directed to complete multiple 1,000-mile oil consumption tests. I complied fully. •2024: Repeatedly redirected between service advisors, received conflicting instructions, misleading guidance, and poor communication. No effective resolution was provided. •2025: Completed extensive additional diagnostic testing as requested. Despite full compliance, no clear corrective action was taken. •2024–Present: Vehicle brought to Hyundai on US 19 in New Port Richey approximately 13–15 times for engine-related concerns. Each visit demonstrated neglect, miscommunication, and failure to properly address documented issues. •February 11, 2026: After proper diagnostics, vehicle found to have two additional oil leaks, including a head gasket and valve cover requiring replacement, with total estimated repair costs exceeding $3,000. I was advised I must repeat all testing already completed in 2024 before final determination. •Vehicle is currently at 71,332 miles. Impact: •Delays and repeated unnecessary testing pushed my vehicle beyond warranty limits. •Mismanagement caused significant financial burden, emotional stress, and frustration. •If initial oil consumption issues had been properly addressed under warranty, the current extensive engine failures could likely have been avoided. Immediate Requests: 1Full review of my complete service and diagnostic history. 2Warranty or goodwill coverage for all necessary engine repairs, including head gasket and valve cover INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

My 2018 Hyundai sonata with only 20,821 had to have the starter replaced on [XXX] because the car would not start. I had 3 different people including AAA road service to verify why it would not start and what the problem was. I end up having my car towed with AAA to a local mechanic shop, Mike Hepler auto repair St. Cloud Florida 34769 407-593-0152, and Mike did the diagnosis saying the starter was bad it was(fried) as he put it. He said he could replace it for $492.17 for part and labor which I accepted for him to do the job. I had left numerous messages (4)for my local Hyundai dealership service department to call me to let get a diagnosis and no one has ever called me back to give them my information or ask any questions.

The contact owns a 2018 Hyundai Sonata. The contact stated the trunk failed to open while using the key fob and the controllers on the interior of the vehicle. The contact had taken the vehicle to the dealer where it was diagnosed that the trunk latch had failed, and the emergency cable associated with the trunk needed to be replaced. The vehicle had not been repaired. The manufacturer was made aware of the failure and a case was opened. The failure mileage was 44,176.

Vehicle 1 operating normally in traffic on [XXX] in Westfield MA. Operator 1 notices alert on dashboard. As Operator 1 looks down briefly and returns eyes immediately to the road, she sees Vehicle 2 braking to slow or stop. Operator 1 depresses brakes, but vehicle does not slow as it usually does, nor does Automatic Emergency Braking engage as it always has in the past. Front of Vehicle 1 makes contact with rear of Vehicle 2. Dashcam footage appears like brakes did not activate at all, either manually or automatically. Vehicle 1 airbags deploy. Westfield Police respond, as well as Westfield Fire, who cut the battery cable. Vehicle towed to Interstate Towing, Inc. Yard 5, 20 Clifton St, Westfield, Ma 01085. (413) 593-1900 interstatetowing.com. Owner 1 viewed vehicle at tow yard, and noted that the battery was completely melted, with only portions of the plastic casing along with internal plates visible. Much of the plastic and rubber components immediately adjacent to battery location were melted and deformed. As a layperson, it almost appears as though the battery was in the process of shorting out just prior to the collision, possibly rendering many of the safety systems inoperable. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

The car was sitting in the parking lot and randomly black smoke started coming from it and then it turned into fire within in minutes. No one was in the vehicle and 911 was contacted.

Car would not start. Odor of burning wires coming from the engine compartment with a little smoke. Had car towed to the Dealer who replaced the starter. Ok for two weeks then same thing. No Start and an odor of burning wires coming from the engine compartment. Had it towed to the Dealer again where it sits today.

We were heading to Lakewood NJ from Bucks County (North of Philly) . Car trouble w/ hybrid system on Rt 1, just past I-95. Got off @ Fairless Hills & took back roads. We could only go 20-30 mph. IDK how many times I pulled over. Several lights on, including "Check hybrid system. Turn Engine off", engine light, low tire pressure, battery & 3 other unidentifiable lights. I turned around to try to make it home, as 2 years ago, I had a similar issue, which turned out to be the hybrid water pump failed. We finally stopped near a park & called AAA & towed to dealer. Prior to driving, we had no fluid on our driveway. My last synthetic oil change was April 19, 2023 @ 49,097mile. I now have about 57,000 miles. Today, dealer said no oil in the car & oil pan was all wet. They claim the oil filer was loose. Why would it take 8 months to loosen to lose oil? After adding oil & taking for test drive, they said the engine seized & would need to be replaced. Not under warranty. Add to complaint - the remaining dashboard lights where checked and non of them was for the oil pressure. If I lost enough oil for the engine to seize I would expect a low oil pressure light to come. The dealer informed me on Dec 26, 2023 that when doing the diagnostic, the oil pressure light came on for them. The photos attached to the case does not show the oil pressure light on.

Intermittent no-crank, no-start condition. Dash lights illuminate, push-button start produces no response. Brake pedal applied. Vehicle becomes immobilized without warning. I’ve been stranded on multiple occasions. Unable to commute to work, or home. Most recently on December 19,2025 the car completely shut off while driving on the highway.

The contact owns a 2018 Hyundai Sonata. The contact stated that the vehicle failed to start in cold weather, below 50 degrees Fahrenheit. The contact stated that the vehicle would start as needed whenever the weather was warmer. The vehicle was taken to an independent mechanic, where it was diagnosed; however, the cause of the failure could not be determined. The dealer was notified of the failure. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 72,000.

Car continues to burn oil within a week of getting oil changes, the oil will be black and it will be low sometimes there will be no oil and there is not an oil leak. Right now we had to pay for a combustion test and have to drive 1,000 miles then check the oil at Hyundai again and already our oil is starting to burn and is low. Hyundai said if the combustion test comes back still burnt or low Hyundai would give me a new engine and yea it’s low and already a tint dark not as dark as it used to get but still it’s low with no leak and we did not get the promised new engine after paying almost 600$ for the test… Also electrical wise the computer randomly sounds like static when Siri talks also the music does not play and randomly the maps will close out we have tried new cords we have tried everything and it still happens.

My 2018 sonata has been stalling out while I’m driving more so when I accelerate.I have a baby that I’m scared to drive with in the car because it does it randomly. It has been happening more & more everyday. I got new parts/starter etc. No codes on dash. Have an appointment next week with Hyundai to take a look.