2018 Hyundai Sonata: stuck in gear or won't shift

Filed Oct 15, 2025 · Engine · PA

In December 2024, my 2018 Hyundai Sonata went into limp mode after the knock sensor was triggered. This happened when my son was driving home from school. I took it to my local mechanic and he said the car was low on oil. We put more oil in it and reset the sensor. In March, the knock sensor was triggered and it again went into limp mode while my son was driving back to school. We took it into a shop and it was again low on oil. Oil was added and then the sensor was reset. The sensor went off again later in March and our mechanic told us to take it to Hyundai and have it checked for the rod bearing issue common with this model and year of Hyundai. He cleared the error and when I contacted the dealer, they said they needed the warning lights on to do a diagnosis. The car was driven for 4 months and the knock sensor went off again. I took it to the dealer and they checked the bearing clearance and it passed the test. The oil was also low and the dealer recommended doing a combustion chamber clean. I spent $564 to get the combustion chamber cleaned. Less than three weeks later, the knock sensor went off again. I took it to the dealer and they measured the bearing clearances and they came back as "passed". I elevated the complaint to Hyundai and they responded that they will defer to the dealer technicians' recommendations and findings and did not offer to do anything to help. The dealer the drove the car to see if they could trigger the knock sensor which was unsuccessful. After expressing my disappointment and dissatisfaction, the dealer said there was nothing else they could do and the car was returned to me. I am concerned with the safety of this vehicle as entering Limp Mode on a highway represents a safety issue that Hyundai does not seem to be concerned about.

Filed Aug 18, 2025 · Electrical, Engine · OH

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.

Filed Apr 22, 2025 · Transmission · NC

The car went into limp mode they have problems with the knock sensor and that is what it threw to the computer and I changed the sensor and went away and now limp mode again and computer says basically the same thing there is a software update and the engines are failing

Filed Mar 17, 2025 · Engine, Transmission · FL

I was going 80 mph on the interstate and suddenly my car went into limp mode and shooked really hard and dropped to 60 mph. I had to swerve to go onto the side of the road. The car behind me almost rammed into me. I contacted hampton hyundai for days to schedule an appt. I finally was able to drop off my vehicle to them but now they are telling me they have to do an oil consumption test but my car is in limp mode and it shakes when I drive it. The car is dangerous and they are trying to charge me $500 for a fuel pump replacement ( which I have a warranty of but they notified me that does not count but it matches exactly the possible reason). As you can see in the documents, they did not note that my fuel pump was broken. They just asked if I wanted to pay it so they can get started. I get normal oil changes done. They haven't even done a rod bearing test but just looked at the knock sensor and was telling me that they wanted to charge me to get that changed.

Filed Dec 31, 2024 · Engine, Fuel system · NC

- Component or system that failed: engine (cylinder #4 misfire) - Safety was put at risk twice: once when knock sensor went off on interstate (October) and engine went into limp mode (aka protection mode). Required a tow from the, which was tricky with a vehicle full of passengers. Safety was put at risk gain when vehicle began to stutter/sputter on interstate (December). Drove 4-cylinder vehicle essentially on three cylinders an hour to dealership - Problem has been confirmed by dealer (Southern States Hyundai, Raleigh, NC) - vehicle has been inspected by warranty inspector, who requests approval before disassembling engine to diagnose issue. However, based upon maintenance records and manufacturer's history of engine issues (more on this below), owner should not be liable for investigating a well known issue. At the time of this writing, the issue has been escalated beyond the dealership and warranty to Hyundai Motor America, and currently awaiting the results of their findings. - symptoms of the problem include constant oil leak from vehicle purchase in May 2024 up to engine failure in December 2024. Various temporary remedies (oil changes and repairs, including oil drain plug gasket replacement, crush washer replacement, and replacement of cracked oil pan) did not fix the issue. Additionally, in the October incident, Hyundai dealership (Sport Durst Hyundai, Durham, NC) simply updated the knock sensor detection (KDS) software, despite the vehicle previously receiving the update in 2019 (this can be verified). Finally, owner, noted "engine knocking" (aka 'tapping') in vehicle prior to engine failure. - Hyundai (the manufacturer) settled a class action lawsuit in 2021. Vehicle is one of the vehicles listed under Class Vehicles, but dealer, nor warranty company, nor Hyundai seem to want to resolve issue, which both alienates owner and presents a safety hazard, as the vehicle is unsafe to drive. All claims here will be supposed via documentation and images.

Filed Dec 8, 2023 · Transmission · 107,000 miles · UT

The contact owns a 2018 Hyundai Sonata. The contact stated while driving 70 MPH, the vehicle went into LIMP Mode and lost motive power. The contact was able to pull to the side of the roadway, where the vehicle failed to restart. The check engine warning light was illuminated. The vehicle was towed to an independent mechanic, who determined that cylinder #1 was misfiring on every cycle due to damage to the piston. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was 107,000.

Filed May 4, 2022 · Electrical, Engine · PA

I was stopped at a red light and when it turned green, I began to accelerate. The car stuttered and the check engine light was blinking. I pulled over and had Autozone run the code. The code is P1326, engine knock sensor. It was put into limp mode and it shook pretty bad in lower gears while accelerating. I had to pull over and let several cars pass me as I couldn't go above 2,000 RPMs. When I got home, I called roadside assistance and had it towed to the nearest dealership. That was this morning (5-4-2022). I just purchased this car used in the beginning of March. I don't have all the records since I just purchased the vehicle used. I just changed the oil last week.

Filed Dec 10, 2020 · Engine · 99,000 miles · WA

I was driving in another city and my car went into limp mode. I had it towed to nearby dealer and they said I was low in oil, after having it changed an month before. They did oil consumption test and found it to be 1 quart per 1000 miles and left there and 2 months later had another consumption test done after seeing my car was one in the class action on engine and bearings. They found this one to be 1.1 qts per 1000 miles. Dealer said no way will they send info to get a new engine under warranty. A qt a 1000 miles seems very excessive. Dealer said that you need to be at 1.5 qt per 1000 which would be almost no oil when I go have an oil change. The vehicle is only 3 years old and 100000 miles. This seems like too much oil to be burnt. And they know they have engine issues and will not rectify

Filed Jul 24, 2019 · Electrical, Engine · 15,000 miles · IL

Tl* the contact owns a 2018 hyundai sonata. While exiting the interstate at 60 MPH, the vehicle went into limp mode, jerked, and failed to accelerate. In addition, the check engine warning indicator illuminated. The vehicle was towed to auffenberg hyundai (located at 1300 central park dr, o'fallon, il 62269, (618) 622-9001) where it was diagnosed that the nox sensor failed and needed to be replaced. The contact stated that the vehicle was repaired for the third time. The contact also stated that the technician reset the computer, the wiring harness was replaced, and the nox sensor was cleaned; however, the failure recurred. The vehicle was also taken to an unknown dealer in tx, but the failure code could not be recreated. The dealer reset the computer and replaced the nox sensor, but the failure recurred. The manufacturer was notified and provided case number: 15894913. The approximate failure mileage was 15,000.

Filed Apr 23, 2019 · Electrical, Engine · 11,000 miles · LA

On 03/23/2019, when I was leaving a parking lot my car started to hesitate and would not rev up. I just turned out the parking lot when this happened. Message came on stated it need to be serviced. At the same time the engine light came on. I was not able to press the accelerator because it would jump like crazy. I was able to get back to the parking lot safely. I have been in a rental for a month now and as of 04/23/2019 I was told the part is on back order. The wiring harness and the computer has to be replaced, but the tech stated since the car went into limp mode the engine will need to be replaced. I was told the part will be in about 3 to 6 months. If the wiring harness does not work god only know how many more months it will take for a new engine to arrive. This car was only 9 months old but now 10 months old with one of the months being in the shop waiting for repairs.

Filed Apr 8, 2019 · Engine · 35,000 miles · IN

January 2019, vehicle to dealer for recall for engine failure. March 2019, went to start vehicle. Flashing engine light. Could not get above 2000 RPM. Dealer advised to tow vehicle. Dealer advised car is in limp mode. Dealer advised possible engine replacement. Two weeks later, car is still not repaired. Now they are possibly replacing 'harness'. Advised that they would have vehicle another two weeks.

Filed Feb 11, 2019 · Engine, Transmission · 5,400 miles · MD

I went into purchasing dealer for first oil change at 5100 miles, they flashed computer and loaded update hyundai campaign 953 product improvement. About 50 miles after the recall was performed my car went into limp mode and is barely driveable. Car was also hesitating, and bucking a bit. Took it back to dealer they stated the code didn't apply to my car and flashed it again. It again went into limp mode after 50 miles or so. The recall is supposed to place the vehicle in limp mode due to rod bearing wear. My car has 5,400 miles on it and it now at a different dealer. Got information from that dealer regarding a tbs #19-01-002 and looks like engine replacement or wiring harness.