2020 Hyundai Elantra engine problems

“The car went into 'limp mode' after rpm fluxuation. It's in the shop. Blake, a service manager at Temecula Hyundai, tells me it has "piston slap," which AI says is related to a piston ring recall for this car. Blake went on to say it has 2 power train issues (and needs a catalytic converter). NHTSA shows no recall, but whether engine or transmission, my daughter was nearly rear-ended due to this mechanical failure occurring on a two-lane highway at 55 mph. RE: Transmission (copied from Facebook): "Summarized by Meta AI " "Several 2020 Elantra owners describe shuddering, hesitation, and complete transmission failure at low mileage. Some report the car won’t accelerate from a stop or surges in RPM while cruising. Hyundai issued a recall for shifting issues that a software update can fix, but not all owners have been notified." It seems to me that the incident could have been transmission and the the engine 'piston slap' is conincidentally simultaneously discovered by Temecula Hyundai. Naturally, I conferred with AI as to the possibilities and found both transmission software recalls and a piston ring recall both a matter of record, but somehow not fully reported…”

“2020 Hyundai Elantra, VIN [XXX], ~79,239 mi. On or about [XXX], while entering a parking lot at low speed on an incline, I pressed the accelerator but the car had severe power loss and then stalled. It would not move in reverse. All dashboard lights came on only after the stall. I restarted it; the lights cleared. It was towed to Westlake Hyundai, 3610 Thousand Oaks Blvd, Thousand Oaks, CA 91362; checked in Sep 29, 2026 8:59 AM. Dealer found engine oil below the low mark, no external leaks, DTCs P0302/P0304 (misfires cyl 2 & 4), and all spark plugs worn/fouled. They replaced the plugs and started an oil consumption test per TSB 23-EM-008H. Critical safety issue: the oil pressure warning light never illuminated before or during the stall, despite critically low oil. This removed my only warning to pull over safely. A sudden stall in traffic could cause a crash. The vehicle has the 2.0L Nu MPI engine covered by Recall 21V301 for defective piston oil rings causing excessive oil consumption and engine failure. My VIN is not included, but it shows the same failure. Vehicle is available for inspection. No police/insurance inspection. Manufacturer not yet inspected.…”

“Back in early July, I noticed a ticking sound coming from my engine so when I took it in to a Hyundai dealership, they told me the only way I could pursue any help further was by completing a oil consumption test, which I complied and paid for out-of-pocket very soon after within 48 hours my check engine light came on and was flashing. after pulling the code at an AutoZone which I have documentation of it was a P 1327 which signals that the car had entered limp mode. I very quickly reached out to Hyundai themselves and after going back-and-forth on paperwork, they assured me that since I had no coverage on the vehicle due to its mileageand that it was not produced in the same factory as the other recall vehicles with that same problem that they could not pay or help me with any of the services I would need done to my engine. They told me the only chance I had was by completing the oil consumption test, which would then put me and my safety at risk by driving a car with a faulty engine while it was also in limp mode. I’ve only had the car for about a year and a half when it threw the first sign at me and I’m now struggling to figure out how to afford a…”

“The contact owns a 2020 Hyundai Elantra. While driving at an undisclosed speed, the vehicle suddenly shut off without warning. The contact referenced NHTSA Campaign Number: 21V301000 (Engine) as a potential cause for the failure; however, the VIN was not included in the recall. The contact stated that the vehicle shook violently with an abnormal electrical wire burning odor. The manufacturer was notified of the failure. The vehicle was taken to an authorized dealer, where it was diagnosed with an engine starter failure. The engine starter was replaced; however, the failure persisted. The failure mileage was 102,474.”

“The vehicle entered limp mode. The Hyundai dealer diagnosed a camshaft problem, said the repair would be covered, ordered the part, and began the work. After the engine was opened, the dealer noted sludge/varnish and denied coverage, claiming lack of maintenance. This VIN is included in safety recall 21V301 for improperly heat-treated piston oil rings on the 2.0L Nu MPI engine. Hyundai told NHTSA that chipped rings can scuff the cylinder bore, cause accelerated oil consumption, knocking, oil-pressure warning, connecting-rod bearing seizure, stall, and in limited cases fire. The published remedy is inspection of the cylinder bore and piston skirt, engine replacement if damage is found, and PNSS software, at no charge. Hyundai National Consumer Affairs Case #XXX. I sent a written demand that they complete Campaign 203 and not convert an open safety recall into a customer-pay job. On XXX, case manager Mohammad issued a letter denying only “limited warranty” coverage for lack of Owner’s Manual maintenance. That letter does not state whether the Campaign 203 bore/skirt inspection was done, does not state whether PNSS was installed, and does not decide the incomplete…”

“2020 HYUNDAI [XXX], VIN: [XXX] Incident Description: On XXX I was pulling into a parking spot and had my foot firmly on the brake pedal. When I attempted to shift the vehicle into Park the engine suddenly revved up excessively. The vehicle then accelerated forward on its own and crashed into a building.”