2017 Kia Optima electrical system problems

“The electrical wiring harness connecting to the hybrid system electric fuel pump(s) was found to have significant corrosion and a missing factory-installed protective covering. This is a manufacturing defect. The protective covering was never installed at the factory, leaving the wiring exposed to moisture and corrosion from the time the vehicle was built. COMPONENT THAT FAILED: Electrical wiring harness to hybrid electric fuel pump(s). Missing factory protective covering caused corrosion. The failed component is available for inspection upon request. SAFETY RISK: Corroded wiring in a hybrid vehicle electrical system poses serious risks including electrical shorts, potential fire hazard, and sudden loss of hybrid propulsion while driving. The vehicle is currently inoperable and unsafe to operate. CONFIRMED BY DEALER: Yes. The vehicle was taken to an authorized Kia dealership where it remained for approximately 8 months. The dealership and manufacturer inspected the vehicle and confirmed the wiring issue but denied warranty coverage. THIRD-PARTY CONFIRMATION: A third-party warranty representative independently reviewed photographic evidence and confirmed the…”

“On March 23, 2026, I took my 2017 Kia Optima Plug-In Hybrid (VIN: [XXX] ) to Mark Kia [XXX] ) solely for two open safety recalls: SC218 (Engine Inspection/Replacement and KSDS software installation) and SC278 (Emergency Trunk Latch Release) under Repair Order #6807251. No customer-pay work was performed. The Multi-Point Inspection that day noted only the cabin air filter. During the drive home on March 23, a faint rotten-egg (H₂S) smell appeared for the first time. By the morning of March 24, 2026, the smell was severe. I immediately returned the vehicle. Under new Repair Order #6807360, a second Multi-Point Inspection suddenly recommended $1,134.10 in customer-pay services (new 12V battery, fuel induction service, cooling system service, brake fluid exchange, and ATF exchange) that were not flagged the previous day. Since the recall service, the vehicle has developed numerous new defects that never existed before: Rotten-egg smell (H₂S) Intermittent AC that blows warm in stop-and-go traffic Passenger-rear power window clicks but will not roll down Brake warning (“Stop vehicle and check brakes”) “Key not detected” message Passenger-side mirror pushed in with…”

“The contact called on behalf of her daughter who owns a 2017 Kia Optima. The contact stated while driving at approximately 60 MPH, the vehicle made an abnormal knocking sound, the cruise control was inoperative, the infotainment screen darkened, and the charging outlet was inoperative. The Check Engine warning light was intermittently illuminated. The vehicle was taken to the contact's residence, and the contact used a vehicle scanner to scan the vehicle. The contact stated that DTC: P1326 for the Knock Sensor Detection System (KSDS) was found, which detected excessive engine vibration. A dealer was contacted; however, the vehicle was not diagnosed or repaired by the dealer. No further information was available. The failure mileage was approximately 98,000.”

“There appears to be an issue with Kia USA regarding an oil switch fault that the company may be aware of but has not addressed through a service bulletin. We own a 2017 Kia Optima with a 2.4L engine and 84,000 miles that has recently started experiencing an intermittent oil pressure light. Thinking the issue was covered under warranty, I took the vehicle in for repair, only to receive a quote of $6,000. The faulty switch had pushed oil through the wiring harness, contaminating the powertrain control module and fuel injectors. I have found information indicating that Kia issued a service bulletin in April 2022 for the same switch used in the 2.4L issue affecting 2015-2018 Kia models with 3.3L engines. However, when I provided this information to the dealer, they insisted the switch in my Optima was different and not covered by the bulletin. I have repeatedly requested the part number for the faulty switch referenced in the bulletin, but have not received a response from the dealer or Kia corporate. The information I found on-line is that the switch in both motors are the same switch. I understand that if this issue is not addressed early, the repair cost can…”

“Since this car did not come equipped with the Anti Theft Immobiliing System, due to recent events like increased theft of Kias and Hyundais ill equipped, an software upgrade was developed by each of the companies. When the dealer performed the anti theft software upgrade to my car, I was not informed at the time of the repair that this software upgrade disables the use of my Kia Remote Starting System. I was told Kia is working on a fix. So, in essence, we need a fix to fix a fix, simply because Kia and Hyundai decided in a cost saving measure to manufacture select years and models that are not equipped with the engine immobilizer key recognition system. I have heard talk of a possible recall for these affected vehicles by the NHTSA. Additionally, my car just manifested an issue today with an illuminated Oil Pressure Indicator Light on the instrument cluster. I have plenty of oil on the dipstick. Could this be more of the same with respect to previous years engine failures.”

“For the past 5-6 months I’m have ongoing issues with my engine and excessive oil consumption. I’ve completed the three oil consumption test per 1000 miles. On the last test(3rd check), I was told I passed and nothing further was needed. Approximately 1 month after that my engine light illuminated and my car violently shook upon acceleration and while sitting idle. Was informed it was my spark plugs and electric coil… oh and a routine oil change, which I paid to have repaired at approx. $650 this was in late August/Early September. Now here we are in late October and my oil lamp is on yet again! My car does not achieve speeds no higher than 50 mph. I’ve been to the dealership 7 times since April 2022. There’s an expense with owning cars but this is ridiculous. I’m currently a few hundred miles shy of 80,000 miles”