2018 Kia Optima Electrical Problems

Your 2018 Kia Optima has shut off unexpectedly multiple times despite replacing the battery twice, spark plugs, ignition coil, valve cover gasket, and belts, plus fuel system cleaning. The car also stalls while driving or idling, burns excessive oil, and has poor acceleration. A mechanic should perform a complete diagnostic to identify the underlying electrical or fuel system issue causing the repeated stalling.

Your car has experienced multiple serious electrical and brake failures. After turning the car off, it became difficult to restart and your brake pedal became very hard; after waiting 30-45 minutes, it returned to normal. Later, warning lights (power steering, battery, and a warning triangle) appeared on the dashboard and wouldn't clear even when revving the engine. Most critically, your brakes failed to respond while backing out of a parking spot, causing you to hit a guard rail, and again failed at a stop sign, forcing you to run off the road to avoid traffic. Kia diagnosed a faulty brake booster and found no engine oil in the vehicle, and you're also noticing the oil warning light flickering on and off with a burning oil smell. Repairs will likely require replacing the brake booster, addressing the electrical system failures, and investigating the engine oil depletion and related warnings.

Your engine failed completely while you were driving on the highway, leaving you stranded. The Kia dealer diagnosed a complete engine failure, but the selling dealer won't honor the limited warranty and appears to have withheld recall information during the sale. Addressing this will likely require a full engine replacement or rebuild.

You took your 2018 Kia Optima Plug-In Hybrid to a dealer in August 2025 for a recall inspection and software update. The dealer said the work was completed, but when you checked NHTSA's database in November 2025, the recall still showed as incomplete — even though Kia later sent you an email saying it was done. This creates confusion about whether the engine safety recall was actually performed on your vehicle. You're asking for written proof and diagnostic reports to verify the work was completed and for NHTSA to correct its records.

My cars bulbs have been blowing on a regular basis for two years..some of the bulb connections are catching fire and exploding .Ive changed on numerous occasions but doesn’t matter even with new fittings…obviously an electric problem

The car is literally burning through oil so bad every other week I am putting more in, the electrical system continues to fail and shorts, the motor sounds like it is ticking now due to the oil consumption.

While driving at night if the headlights will randomly turn completely off

Engine is burning oil at a high rate have to add at least three quarts twice a week and headlights and brake lights got out twice a month

Oil pressure switch faulty only has 58168

In case of a vehicle lockout and keys are locked in the trunk when car is opened by locksmith there is no way to unlock the trunk from inside of the car the locks become disabled and you have to reset the master switch very inconvenient for emergencies. There is no trunk release or emergency Button to open the trunk from inside the vehicle. 2018 kia optima lx

Was driving on the interstate. The only light on was the ABS light and the car started smoking. Had to come to a stop as they were sparks coming from out under the car through it into park at around 15 mph steel jumped out of the car and within a minute the car was fully engulfed in flames.

The engine consumes all the oil within 1000 miles. The oil light comes on around 800 miles after oil change. The dealership did the 3 separate tests and they all failed. Dealership stated the engine is faulty however Kia corporate denied the claim. There is already a class action lawsuit in progress in California.

Normally, when the doors are open my car will tell me. The doors notify me that they're open but my trunk was not showing that it was open. It blinks when it is. Due to that I was driving and my trunk seemed closed and it just flew open. So the problems I'm having is that my trunk will not show its open but it also will not close AT ALL due to the latch. I literally had to bungee it closed. This is dangerous. I have seen many recalls in other kia's and hyundai's just like this. This is very dangerous and needs to be recalled and/or fixed.

Rough idle, chugged along before killing engine power. Has happened a couple of times. No check engine light has come on

When headlight switch is set to automatically come on, the light will sometimes randomly turn off. No warning or indicator on the dash appears showing that they are off. Technicians are unable to reproduce the issue in the shop. Have recommended replacing the entire headlight switch on the turn signal stick.

Me and my family just returned home from the laundry mat and took 2 children inside our house and turned around for our belongings and clothing/bedding for the family as the wheels spun out being followed by a silver hyundaii. Just a matter of seconds to 2 minutes. The keys were not in the vehicle. 2 childrens carseats and almost ALL of my family's belongings were stolen inside of the vehicle. 2018 kia optima dark slate grey in color with dark tinted windows and sun strip at the top of windshield, black rims. CR 21077 IL LICENSE PLATE This seems to be an ongoing issue with kia and hyundaii vehicles being stolen and somehow im still not being offered a loaner vehicle with full coverage insurance

My car has been at the dealership since February 10th. The dealer has been giving me the run around. Didn’t have any transportation for over two months and car hasn’t moved since the day I dropped it off. I’m really getting impatient, as I am making monthly payments on a car that I can’t even use. Nearing four months and I’m totally lost on what to do. Thank you for any assistance

The headlights on my 2018 Kia Optima have been turning off and on randomly by themselves while in motion. Each time it's happened has been in different areas at different times of the night. The headlight switch is kept in the auto position most of the time. When the headlights turn off, the screen in the dash for the headlight function switches from auto to off by itself. Sometimes if the turn signal switch is jiggled the lights will come back on. Other times the headlight switch, located on the end of the turn signal switch, has to be turned to the on position to get the lights to turn on. The car has been in for service but each time the technician is unable to reproduce the fault. It is occurring more frequently and becoming a safety issue.

The electrical components connected to the headlights seem to be faulty. When lights are set to AUTO, the lights will turn off completely when switching on turn signal. At times the light will not come on at all when set to AUTO or On without cycle back to off.

Vehicle is making a noise when trying to accelerate. Have replaced all spark plugs and coil #4. It is making noise still and shaking. Coil has been switched and issues are reading fuel injector or air intake or electrical. Previous reading was head gasket... Only on spark plug 4 coil is it reporting an issue...All dealerships locally are booked to even get a diagnostic test.

While driving, car in motion, Front Passenger Seat belt Audio Warning Periodically goes off without reason. Indicating seat is occupied & seat belt needs putting on. When seat has been unoccupied / clear from any type of weight on seat to trigger sensor. Audio warning will continue until seat belt is latched over the empty seat. Local KIA Service Dept was informed & could neither confirm or deny its faulty behavior for it did not present itself during time of service. They said, wiring looked fine but did no further testing. To be honest they showed no interest into seeing any real importance for my concern for them to feel any further investigation was warranted. Its happened again twice since that service visit be it last incident Aug 7th. My concern is.... if there is faulty wiring or sensor signals being crossed somewhere, whats to say there is a passenger or no passenger in that seat, to ensure the correct signal is getting to the passenger side air bags of when to correctly deploy if an accident should happen with passenger in seat? This situ is only recent starting about a year a go. So something has changed from being fine for 2 yrs up to the last year that's now showing some kind of seat belt / sensor failure. I'm unfamiliar with how that wiring system works & linked within it for me know what other things I might need to pay more attn to, looking for other signs that could be saying is direct cause to the prob. Unsure if this a simple solution or is something that others are experiencing with this year & model car & poss be a Manufacturer Part Default

2018 KIA OPTIMA EX. SOMETIMES HESITATES WHEN TRYING TO START, UNTIL TODAY. ALL LIGHTS ON DASH LIT UP BUT NO IGNITION. I TRIED SEVERAL TIMES, THEN STEERING AND BRAKE PEDAL LOCKED UP AND I HEARD CLICKING NOISE. HAD SOMEONE JUMP MY BATTERY AND THE CAR STARTED UP, BUT WHEN I TURNED IT OFF, IT WOULD NOT START AGAIN. NOTHING WAS LEFT ON ALL NIGHT, CAR WAS LOCKED AND UNLOCKED WITH HANDLE. I AM CONTACTING THE DEALER THIS AFTERNOON TO SEE HOW THEY HANDLE THIS.

MY CAR SUDDENLY EXPERIENCE MAJOR ELECTRICAL ISSUES. I DROVE MY CAR TO THE STORE AND BACK HOME. I WENT BACK TO MY CAR AND IT STARTED WITH NO PROBLEM BUT MY DASH WAS FLASHING, MY BRAKE, STEERING, CHECK ENGINE, AIRBAG, ABS, AND TRACTION'S CONTROL INDICATORS CAME ON ALL AT ONCE. I WAS NOT ABLE TO SHIFT THE CAR INTO GEAR. I USED THE PARK RELEASE SHIFT TO PUT THE CAR IN GEAR AND THE CAR HAS NO POWER STEERING. BUT IT MOVES. I TOOK IT TO THE JEFFERY KIA IN ROSEVILLE,MI AND BASICALLY WAS TOLD THAT THEY DIDN'T KNOW WHAT WAS WRONG WITH CAR. THEY ASK ME HAD MY CAR BEEN STRUCK BY LIGHTNING! YOU CAN LOOK AT THE CAR AND SEE THERE HAS BEEN NO ACCIDENTS OR LIGHTNING STRIKES TO THE CAR. THEY WANTED TO CHARGE ME EXTRA MONEY TO KEEP THE CAR JUST TO TELL ME WHAT'S WRONG WITH IT. I KNOW THIS IS A DEFECT WITH THIS VEHICLE. I SEE THE EPD RECALL ON 2018 KIA OPTIMA BUT THEY ARE SAYING IT'S ONLY FOR HYBRIDS. WHICH IS FALSE THIS HAS TO BE HAPPENING TO ALL THE KIA OPTIMA MODELS.

WHILE DRIVING AT NIGHT LIGHTS WENT COMPLETELY OUT ON HIGHWAY WHILE IN AUTO MODE

TL* THE CONTACT OWNS A 2018 KIA OPTIMA. WHILE REVERSING THE VEHICLE, THE REAR AND SIDE SENSORS FAILED TO IDENTIFY TWO PEOPLE WALKING PAST. THERE WERE NO WARNING INDICATORS ILLUMINATED. THE VEHICLE WAS TAKEN TO SUNSET KIA OF AUBURN (3401 AUBURN WAY N, AUBURN, WA 98002, (855) 474-9626) WHO STATED THAT THE SENSORS WERE WORKING AS DESIGNED. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE MANUFACTURER WAS NOT CONTACTED. THE FAILURE MILEAGE WAS 14,356.

TAKARA RECALL VEHICLE POWER DOWN WHILE I WAS DRIVING 45 MPH ON A CITY STREET THE CAR WAS STATIONARY IN MOTION THEN POWERED BACK UP WITHOUT ME TURNING THE IGNITION.WAS A VERY SCARY EXPERIENCE

THIS HAS OCCURRED ON 3 TIMES SO FAR. I WAS AT A GAS STATION FILLING UP THE TANK, THE KEY WAS IN THE IGNITION, THE CAR WAS IN PARK, THE ENGINE WAS RUNNING, AND MY CAR DOOR WAS CLOSED. WHEN I FINISHED GETTING GAS, I TRIED TO OPEN THE DRIVER SIDE DOOR AND IT WAS LOCKED. ALL DOORS WERE LOCKED. I WAS 20 MILES FROM HOME FORTUNATELY SOMEONE WAS AT HOME TO BRING A SPARE KEY FOR ME TO OPEN THE TRUNK, PUSH THE REAR PASSENGER SEATS DOWN AND CLIMB THRU TO THE FRONT TO TURN THE IGNITION OFF AND UNLOCK THE DOOR. THE SAME SCENARIO OCCURED THIS PAST WEEK WHEN I HAD GONE OUTSIDE TO WARM UP MY CAR BY TURNING ON THE DEFROST FOR THE FRONT AND BACK WINDOWS. ONCE AGAIN, THE ENGINE WAS RUNNING AND I CLOSED THE DOORS. ONCE THE CAR WAS WARM, I TRIED TO OPEN THE DOOR AND IT WAS LOCKED. I HAD TO GO IN THE HOUSE TO GET THE OTHER SET OF KEYS, OPEN THE TRUNK PUSH THE BACK SEATS DOWN AND CLIMB THRU THE TO THE FRONT, TURN OFF THE IGNITION AND UNLOCK THE DOOR. THIS LAST OCCURENCE WAS ONCE AGAIN AT A GAS STATION, THIS TIME IT WAS LATE AT NIGHT, IT WAS 20 DEGREES OUTSIDE AND HAD TO WAIT FOR SOMEONE FROM MY HOUSE BRING THE SPARE KEYS. THE QUESTION I HAVE FOR MYSELF IS, WHAT AM I GOING TO DO IF NO ONE IS AT MY HOUSE TO BRING THE EXTRA KEY. SURELY, I DONT PLAN TO BRING TWO SETS OF KEYS WITH ME. EVERYTIME I'VE TAKEN IT TO THE KIAOFDAYTON SERVICE CENTER, I AM TOLD THEY CANNOT RECREATE THE ISSUE. I'VE TAKEN IT TO THE DEALERSHIP TWICE. IT'S VERY FRUSTRATING. IN EVERY INSTANCE THE CAR WAS IN PARK, THE ENGINE WAS RUNNING, AND THE DOORS WERE UNLOCKED WHEN I HAD EXITED THE VEHICLE. WHEN I ATTEMPTED TO GET BACK IN, I COULD NOT BECAUSE THE DOORS HAD LOCKED BY THEMSELVES.