2021 Hyundai Tucson Problems

What owners report

Owners of the 2021 Tucson report mostly engine-related problems, especially the engine going into limp mode after a flashing check engine light, often tied to a P1326 knock sensor or rod bearing fault, and excessive oil consumption that can leave the dipstick dry between changes. A second, smaller group of complaints concerns the ABS hydraulic control unit recall (20V543000), mainly about parts and appointments being unavailable, plus occasional reports of forward collision braking on its own. Reported mileages range widely, from vehicles under 10,000 miles to ones past 100,000.

1. 1
   Engine

   Limp mode with flashing check engine light (P1326)

   • 18 complaints (23%)
   • median 89,000 mi at 4.1 yrs old (3 state mileage, few)
   • filed 2023–2026

   Owners describe sudden loss of power, a flashing check engine light and a vehicle limited to low speed or roughly 2,000 RPM. Many say a P1326 knock sensor code was retrieved, and that dealers either replaced the knock sensor, applied a software update, or told them the engine needed replacement. Several report the condition returned after repair, including after the knock sensor campaign was performed. Reported from roughly 15,000 miles upward, with some repeats past 40,000 and near 90,000 miles, and often occurring at highway speed.

   3 related service bulletins

   What to check: Ask whether the knock sensor detection software update has been applied and whether any P1326 history or engine replacement shows in service records. A pre-purchase scan for stored codes is worthwhile.

   2 excerpts from owner complaints in NHTSA records

   “My check engine light came on in the vehicle and immediately the acceleration declined and I wasn’t able to go above 50 mph. I brought the vehicle to the dealership to which the code 1326 came up. I was told it is a rod bearing engine failure and I need a new engine for the vehicle. I was also told my vehicle doesn’t qualify for the recall already made for this damage and code number.”

   NHTSA complaint #11608558, filed 2024-08

   “My family’s safety is at serious risk with my 2021 Hyundai Tucson, which I’ve owned only 55 days. This vehicle has stalled three times while driving, putting me and my two young children in immediate danger. Each time, the car operated normally until a flashing engine light appeared, RPMs spiked, and the vehicle suddenly lost all power—entering “limp mode” and unable to exceed 3,000 RPM or 50 MPH. …”

   NHTSA complaint #11697088, filed 2025-11
2. 2
   Brakes

   ABS control unit recall not completed (parts unavailable)

   • 9 complaints (11%)
   • median 1,100 mi at 0.5 yrs old (1 states mileage, few)
   • filed 2021

   Many complaints are about the ABS hydraulic control unit recall rather than a fresh failure: owners say they were told the part was on backorder and that appointments were booked far out. Some describe being advised to park outdoors and away from structures in the meantime, and a few report selling or delivery issues around an open recall. Reported throughout 2021 and beyond, usually soon after the recall notice was received.

   Recall 20V543000

   What to check: Confirm by VIN whether recall 20V543000 has actually been completed with the new control unit, not just scheduled.

   2 excerpts from owner complaints in NHTSA records

   “Received recall notice that the possibility exist that a battery compartment fire could happen. Recall notice also stated that vehicle should 'not be parked indoors.' the recall notice also stated 'an electrical short in the ABS module could increase the risk of an engine compartment fire.' so we don't dare park the car in our garage since it is located beneath our home, thereby leaving a new car out in the elements at all times. …”

   NHTSA complaint #11413920, filed 2021-04, 1,100 miles

   “Hyundai Tucson anti-lock brake system modules corrode internally and cause an electrical short and fire. They issued a recall, and their notices say it will take less then one hour to perform installation of new ABS modules, yet all dealerships say it takes half a day. I just visited a dealership who didn't even have the parts to do it!!! And each service department only schedule 5-7 recalls per day. So all dealerships are booked for months and months out. Leaving us all with this very dangerous defect, threatening to burn down our homes. …”

   NHTSA complaint #11403623, filed 2021-03
3. 3
   Engine

   Excessive oil consumption between changes

   • 11 complaints (14%)
   • median 66,903 mi at 5.0 yrs old (2 state mileage, few)
   • filed 2025–2026

   Owners report the oil level falling below the dipstick minimum well before the next scheduled change, with no visible leaks and sometimes no low-oil warning. Some say dealers ran an oil consumption test; others report being told the engine needed replacement after the consumption was confirmed. Reported across a broad mileage range, from about 24,000 to 90,000 miles, typically between oil change intervals.

   2 related service bulletins

   What to check: Check the dipstick after a short drive and compare against the last oil change record, and ask whether a consumption test was ever performed.

   2 excerpts from owner complaints in NHTSA records

   “My car is burning oil. I have returned multiple times to have it serviced and checked for leaks, but no leaks have been found. Before reaching the recommended 3,000-mile oil change interval, the oil level drops below the minimum mark on the dipstick. In addition, my engine has started making a knocking noise, which is very concerning.”

   NHTSA complaint #11743079, filed 2026-06

   “This vehicle burns oil at an alarming rate. I am getting oil changes every 3K miles, and when I take it in, the dipstick is dry. I receive no oil lights to tell me it is low. I just had to get spark plugs and the mechanic at the garage told me this was due to the oil consumption issue in these vehicles. I am at 71,000 miles.”

   NHTSA complaint #11752252, filed 2026-07
4. 4
   Engine

   Engine noise and engine failure (knocking, replacement

   • 19 complaints (24%)
   • median 52,403 mi at 4.2 yrs old (6 state mileage, few)
   • 1 mention a crash, fire or injury
   • filed 2023–2026

   Complaints describe a knocking noise from the engine, sometimes followed by the oil pressure light and a stalling or non-starting vehicle. Owners say dealers diagnosed rod bearing damage or a failed engine and recommended replacement, with some reporting their request for coverage was denied or still pending. Mostly reported between roughly 25,000 and 90,000 miles; a few at very low mileage shortly after purchase.

   2 related service bulletins

   What to check: Listen for rhythmic knocking on a cold start and after warm-up, and ask for the full engine service history, including whether the engine has already been replaced.

   2 excerpts from owner complaints in NHTSA records

   “I have been adding oil to this engine excessively for more than 3 years..I have had appointments with the dealer where they flat out told me bring it back when the engine fails.i finally got N appointment and was told the engine needed to be replaced.that was 2 weeks ago..they are now denying the claim...have had my car for 2 weeks..no loaner..and decided to deny what they told me”

   NHTSA complaint #11712752, filed 2026-01

   “2 years ago I had the engine replaced. Now on this new engine which has approximately 29k. The mechanic is telling me that I need a new engine. I called Hyundai and their telling me that is not under warranty anymore. What can be done?”

   NHTSA complaint #11736406, filed 2026-05
5. 5
   Forward collision avoidance

   Forward collision system warnings or unwanted braking

   • 6 complaints (8%)
   • median 69,493 mi at 5.7 yrs old (1 states mileage, few)
   • 1 mention a crash, fire or injury
   • filed 2021–2026

   Owners report a 'check forward collision system' message, a warning light, and in some cases the system braking on its own or staying on when it should not. Complaints describe dealer diagnoses such as a camera circuit fault, and at least one owner says the vehicle was not repaired. Reported mostly between about 16,000 and 70,000 miles.

   What to check: On a test drive, confirm there are no forward collision or camera warning messages, and ask whether any related software update or camera repair has been done.

   2 excerpts from owner complaints in NHTSA records

   “Forward crash avoidance system keeps activating causing the car to brake on it's own. This was previously fixed on my car once back in 2022 and now in 2026 it is happening again. I have been trying to communicate with Hyundai regarding additional years to current recall but their not going to even though they have known for years this was an issue and included older models than their current recall. …”

   NHTSA complaint #11746359, filed 2026-06

   “I bought a brand new 2021 Hyundai Tucson on 1/1/2021. I found out on 1/10/2021 that there was an active recall on my car. After looking through the laws it states that a car dealership is legally not allowed to sell a car that has an active recall. When I called the dealership they verified that they received the recall information for that specific car on 12/30/2021 but proceeded to sell it anyways. …”

   NHTSA complaint #11387738, filed 2021-01

Buying note. A pre-purchase scan for stored codes and a check of the oil level and service history are the most useful steps for this model year. Confirming by VIN that recall 20V543000 was completed, and asking about any engine work or knock sensor updates, will tell you more than mileage alone.

Summary written with AI from a sample of 60 NHTSA complaints for this model year (picked at random, with complaints that state a mileage and recent ones taken first), then checked automatically against the source records. Where a problem shows a complaint count, every complaint for this model year was matched with fixed keyword rules (written with AI and tested against the sample), and the mileage, age and repair figures are calculated from those complaints; owners' figures are as stated, not verified. Other counts refer to the sample. The excerpts come from NHTSA's public complaint records and are unverified; capitalisation is normalised, NHTSA staff notes are removed, and shortened text ends with “…”. Something wrong? Request a correction.