Acura RDX 2021 — Reported problems

My 2021 Acura RDX A-Spec AWD had approximately 89,000 miles when this incident occurred on [October 23rd] on I-10 in Tempe Arizona]. My wife was driving when the vehicle displayed emissions and brake-system warnings, lost power and slowed unexpectedly. She was unable to restart it at that time. The unexpected loss of power in freeway traffic created a safety concern. I was subsequently able to drive the vehicle to the dealership. Acura of Tempe inspected the vehicle. Its written diagnosis reported an “ENGINE TEMP HIGH” warning, misfires after the vehicle had been sitting, an empty coolant reservoir and low radiator coolant. The dealer diagnosed a head gasket leaking coolant into a cylinder and recommended head gasket replacement, with further inspection for cylinder-head damage. The dealer provided an approximately $4,000 repair estimate, with potential additional costs depending on the cylinder-head findings. I am reporting the unexpected loss of power and the diagnosed coolant intrusion as a potential safety defect. I can provide the dealership’s written diagnosis and estimate. Approximate speed at the time: 65 MPH. Crash, injuries or fire: [None. Current repair status: [not repaired ].

The contact owns a 2021 Acura RDX. The contact stated that the front passenger’s side seat belt retractor failed to retract as needed. The vehicle was taken to a dealer and was inspected and repaired. The failure mileage was 42,000

Rear window shattered spontaneously twice. 9/12/24 & 10/11/26

2021 Acura RDX has cold start, uses coolant and will stumble, limp mode approaching 2000 RPM. Vehicle will flash check engine light and then will go away when vehicle is restarted. Using search criteria noted TSB issued for same make model and year with an extended warranty being offered through TSB, 10 year 150,000 miles. Vehicle has 103,000 miles. Dealer is stating no TSB for this VIN, however the number one issue noted through internet searches and this database.

Acura Sunnyside in New Hampshire denied to repair my recall on my 2021 Acura RDX.

Engine was replaced 12/13/25 due to cracked cylinder head causing oil to leak into exhaust and fill cylinder 2 and 3. 09/21/26 new engine replacement done in December 25, has now blown cylinder head gasket seal in under 12,000 Miles. Causing coolant to leak into cylinders 2 and 3.

Head Gasket blown known problem with Honda and Acura 2.0T I didn’t know of this issue until it occurred to Loi Me in 2025 My Acura dealership told me it’s a huge problem with the Acura RDXand it should be a warranty extension similar to the warranty extension for other Honda products done in August 27, 2026 I was lucky and my head gasket didn’t blow while I was driving I’m also concerned that it’s gonna happen again I’m not sure if the problem was resolved with the new head gasket or it’s a stomach problem with the motor that has not been addressed yet

Two low-speed sudden unintended acceleration events while parking a 2021 Acura RDX. Incident 1 (July 2026): While parking at low speed, the car unexpectedly surged forward. Flew up the curb and hit a restaurant window, causing massive undercarriage damage. Active braking did not help and seemed to make acceleration worse. It only stopped when it wanted to. Incident 2 (August 2026): Two weeks after getting the car back from repairs, under identical low-speed parking conditions, a second sudden acceleration event occurred. Slamming on the brakes did nothing. It stopped after scraping a car wash vacuum pole, destroying the entire passenger side. Prior to these, the car exhibited erratic safety software behavior, including multiple phantom braking incidents where it slammed on its brakes violently with no obstacles present. I bought the car Certified Pre-Owned two years ago. The dealership repaired a known "popping sound" from the panoramic sunroof frame three times. This required extensive cabin/pillar teardown work, which may have disturbed internal wiring harnesses or grounding points linked to the electronic throttle control system. In both events, it felt like an uncontrolled amusement park ride—the engine loudly revving and taking over with zero driver control. I initially assumed pedal confusion during the first crash, but since it happened again under identical circumstances, there is clearly a systemic electronic/software defect in the Throttle Actuator or Powertrain Control Module. The vehicle is at an insurance network body shop awaiting forensic evaluation of the throttle system, pedal sensors, and a Bosch EDR black box download.

Fuel Pump is having to be replaced. I have had issues accelerating and my car also stalled once on the freeway. It put me in a dangerous situation and I almost got in an accident because my speed quickly decreased. The same part was recalled on the previous year’s model.

I own an Acura RDX that experienced a sudden failure of the transfer case. Prior to the failure, there was little or no warning that a major drivetrain component was about to fail. When the transfer case failed, the vehicle lost its normal all-wheel-drive operation and required expensive repairs. I believe this is a safety defect because the transfer case is a critical drivetrain component. A sudden failure can reduce traction and vehicle control, especially when driving at highway speeds or on wet, snowy, or icy roads. Drivers may not expect the loss of power to the rear wheels, which could increase the risk of skidding, loss of stability, or being unable to safely accelerate into traffic or avoid a hazard. In addition, there are numerous reports from other Acura RDX owners describing similar transfer case failures, suggesting this may not be an isolated incident but a recurring problem. A critical drivetrain component should not fail prematurely under normal use without adequate warning. I believe this issue warrants investigation because it has the potential to affect vehicle safety and place drivers and passengers at unnecessary risk.

I own an Acura RDX that experienced a sudden failure of the transfer case. Prior to the failure, there was little or no warning that a major drivetrain component was about to fail. When the transfer case failed, the vehicle lost its normal all-wheel-drive operation and required expensive repairs. I believe this is a safety defect because the transfer case is a critical drivetrain component. A sudden failure can reduce traction and vehicle control, especially when driving at highway speeds or on wet, snowy, or icy roads. Drivers may not expect the loss of power to the rear wheels, which could increase the risk of skidding, loss of stability, or being unable to safely accelerate into traffic or avoid a hazard. In addition, there are numerous reports from other Acura RDX owners describing similar transfer case failures, suggesting this may not be an isolated incident but a recurring problem. A critical drivetrain component should not fail prematurely under normal use without adequate warning. I believe this issue warrants investigation because it has the potential to affect vehicle safety and place drivers and passengers at unnecessary risk.

I own an Acura RDX that experienced a sudden failure of the transfer case. Prior to the failure, there was little or no warning that a major drivetrain component was about to fail. When the transfer case failed, the vehicle lost its normal all-wheel-drive operation and required expensive repairs. I believe this is a safety defect because the transfer case is a critical drivetrain component. A sudden failure can reduce traction and vehicle control, especially when driving at highway speeds or on wet, snowy, or icy roads. Drivers may not expect the loss of power to the rear wheels, which could increase the risk of skidding, loss of stability, or being unable to safely accelerate into traffic or avoid a hazard. In addition, there are numerous reports from other Acura RDX owners describing similar transfer case failures, suggesting this may not be an isolated incident but a recurring problem. A critical drivetrain component should not fail prematurely under normal use without adequate warning. I believe this issue warrants investigation because it has the potential to affect vehicle safety and place drivers and passengers at unnecessary risk.

I own an Acura RDX that experienced a sudden failure of the transfer case. Prior to the failure, there was little or no warning that a major drivetrain component was about to fail. When the transfer case failed, the vehicle lost its normal all-wheel-drive operation and required expensive repairs. I believe this is a safety defect because the transfer case is a critical drivetrain component. A sudden failure can reduce traction and vehicle control, especially when driving at highway speeds or on wet, snowy, or icy roads. Drivers may not expect the loss of power to the rear wheels, which could increase the risk of skidding, loss of stability, or being unable to safely accelerate into traffic or avoid a hazard. In addition, there are numerous reports from other Acura RDX owners describing similar transfer case failures, suggesting this may not be an isolated incident but a recurring problem. A critical drivetrain component should not fail prematurely under normal use without adequate warning. I believe this issue warrants investigation because it has the potential to affect vehicle safety and place drivers and passengers at unnecessary risk.

While driving only at 35 miles per hour down the XXX in [XXX] my panoramic sunroof suddenly bursts. A loud pop sound. This would have popped all over my body if I didn’t have cover up. This is an extreme problem as someone can die from this. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Vehicle lost all coolant and could be smelled. Vehicle was towed to dealership before it could overheat. Diagnosed with a cracked cylinder head at 88,000 miles. Vehicle has never been modified, tracked, nor has it ever overheated. All service has been performed on time and at Acura dealership since I purchased the vehicle brand new. Vehicle is still at dealership. I've researched and found many other owners experiencing the same problem with the crack occurring in the exact same spot on the cylinder head.

On or about XXX, my 2021 Acura RDX, with approximately 121,078 miles, suddenly displayed multiple dashboard warning lights and system-failure messages while I was driving. These included the check-engine light, Road Departure Mitigation System Problem, steering, stability-control, braking-assistance and other driver-assistance warnings. Earlier, the tire-pressure monitoring system had also indicated a malfunction even though the tire pressures were correct. The vehicle initially continued to drive and the conventional brakes appeared to function normally. However, it then began hesitating when I attempted to accelerate. The vehicle would eventually gain speed, but the initial hesitation created a serious safety concern when pulling into traffic or attempting to accelerate. The check-engine light remained solid while the vehicle was stopped but flashed whenever I began driving and accelerating again. No crash, fire or injury occurred. The vehicle had undergone a full diagnostic inspection approximately two weeks earlier, and I was informed that everything checked out properly. There were no known drivability problems before this incident, and the vehicle has been maintained according to the manufacturer’s recommended service schedule. The vehicle was subsequently inspected by Elite Acura, an authorized Acura dealership in [XXX]. The dealership confirmed a head-gasket failure and a problem with the rear differential left-side actuator. The dealer recommended replacing the head gasket, four spark plugs, coolant, oil and filter, as well as replacing the rear differential left-side actuator and changing the differential fluid. The estimated head-gasket repair was $5,391.46, and the estimated rear differential actuator and fluid service was $813.85. The dealer also recommended rear brake pads and rotors. The head-gasket and rear differential actuator problems were confirmed by the authorized Acura dealership. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

A transmission fluid leak has been identified emanating from the passenger side output shaft seal, located between the transmission and the transfer case. This issue pertains to 2019–2023 Acura RDX and TLX models equipped with SH-AWD, specifically at the interface where the transmission connects to the front transfer case, which is responsible for power distribution to the rear wheels. It appears that the fitment tolerances at this connection point are problematic, suggesting a potential engineering deficiency that warrants a manufacturer-funded resolution..

The contact owns a 2021 Acura RDX. The contact stated that while at a complete stop at a stop sign or traffic light, the engine auto stop-start system was inoperable upon depression of the brake pedal. The vehicle was taken to the dealer, but the failure could not be duplicated. The dealer initially suggested that the battery might require replacement. However, another dealer determined that the battery was functioning properly and exhibited no defects upon inspection. The manufacturer was not notified of the failure. The failure mileage was unavailable.

The Auto High-Beam system activates the high beams inappropriately during operation. The system triggers the high beams directly into the eyes of oncoming traffic and activates during early dusk conditions. The sudden, intense illumination blinds oncoming drivers. This creates an immediate glare hazard and significantly increases the risk of a head-on collision. I reported this specific failure to the authorized dealership on three separate occasions, engaging three distinct service advisors during the active warranty period. The service department omitted these complaints from the formal repair orders. The first advisor stated the system was functioning normally. The second advisor stated the technicians completed an inspection and verified the system as fully operational. The third advisor acknowledged experiencing the exact same malfunction on their personal vehicle and instructed me to manually disable the safety feature. The system fails silently, displaying zero warning lamps or error messages prior to or during the malfunctions. The attached service invoices document a severe, underlying instability within the vehicle's electrical and Advanced Driver Assistance Systems (ADAS) network, culminating in a complete VSA modulator replacement. These records establish a confirmed administrative pattern of the dealership dismissing intermittent safety faults, officially logging statements such as "unable to verify issue" and "no problem found" on subsequent visits. This evidentiary paper trail substantiates the dealership's systemic suppression of my specific, repeated verbal reports regarding the Auto High-Beam safety hazard. The vehicle and the Auto High-Beam system remain available for inspection upon request.

On March 20th, my husband and I went out to dinner with three friends. We arrived around 6:50 PM and left our car with the valet. When we returned later that evening to pick up the vehicle, a valet employee approached us and asked us to walk with him to the car. The police were already present at the scene. The employee explained that when he entered the vehicle on the driver’s side to return it to us, he closed the door and immediately heard the sound of glass shattering. When we reached the car, we saw that the entire rear window had been shattered. The police later reviewed the surveillance footage and confirmed that the incident occurred exactly as described by the valet employee.

The contact owns a 2021 Acura RDX. While driving at an undisclosed speed, there was an abnormal gunshot sound coming from the vehicle. The vehicle was driven to the residence. The contact inspected the exterior of the vehicle but found no failure. The contact stated that the following day, while driving at an undisclosed speed, the panoramic roof glass shattered, and glass shards fell inside the vehicle. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. The manufacturer was not made aware of the failure. The failure mileage was approximately 56,000.

Got in my vehicle as usual, started the vehicle shortly after I heard cracking thought nothing of it and all of a sudden the rear tailgate window shattered completely.

- Rear window shattered without impact or any signs of stress. - Safety at risk if driving and breakage occurs. In this case I was away from the parked vehicle when the shattering occurred. - There are quite a few reports of this issue online in Facebook Acura owner groups and in published news stories such as this: [XXX] - In my case, it was inspected by the repair company and confirmed to be a common occurrence they are called to repair. - There were no warning lights or any signs of damage or stress to the glass. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Infotainment system fails on occasions. Sceen goes completely blank causing distraction while driving. There is currently a recall for this issue for 2019-2020 RDX.

Sudden breaking of panoramic glass on sun/moon roof. I believe this is related to the clicking noise that is caused by the improper bolting in this model. There is an active service bulletin for the improper bolting/flexing in the panoramic glass. I called the Acura dealership where this was bought and they didn’t acknowledge that. I had my two children, toddler and infant, in the back. They like the panoramic open. If this broke on top of them this would be a very serious injury.

Warmed car before driving, once I got in car and shut drivers side, Rear window shattered. Common issue with other owners of same car. Reached out to Acura dealerships and they claim it’s not an issue that is happening and will not replace it.

The contact's sister owns a 2021 Acura RDX. The contact stated that the rear glass had shattered while the vehicle was parked in the driveway. The dealer was contacted and advised that the earliest availability to replace the glass was in 3-4 days. The manufacturer was notified of the failure and a case was opened; however, the manufacturer later informed the contact that the model year was not covered under TSB: 22-014 (Rear Windshield Glass Shattering). The failure mileage was approximately 60,000.

After dealer (worldwide motors Ltd also call (Paragon Acura) 33-40 57th street, Woodside, NY 11377)replaced front and rear brake pads and rotors, my vehicle experienced unintended acceleration while stopped. While idling at a red light with my foot firmly on the brake pedal, the vehicle suddenly moved forward approximately 10 feet on its own. This was a serious safety concern and nearly caused a collision or pedestrian injury. I immediately returned the vehicle to the dealer. The dealer stated they could not duplicate the issue and said the vehicle was operating normally. No warning lights were present. The incident occurred immediately after brake service. I am concerned this may involve the braking system, brake booster, brake switch, or electronic throttle interaction. This behavior is not normal and poses a safety risk.

Back windshield glass exploded with no impact. Car was not moving. There is shattered glass everywhere and the car cannot be driven until it is repaired. This appears to be a well known issue but there is no official recall at this time. My Acura dealer said this was covered in warranty that expired in November. The incident happened December 13, 2025.

Back windshield shattered and blew out with zero impact. Car was parked Manufacturer denies responsibility . Independent company repaired because dealer was booked and needed fixed quickly. No one injured glass all over back of car and trapped in base of doo now because of faulty design. No warnings at all.

1:Sunroof frame shifts creating a popping noise during certain driving conditions. Turning and going up a drive way. 2:Distracting for the driver and passengers stay concerned the whole time. 3:There is a service bulletin with Acura 23-004 but no recall to the matter. 4: Unknown 5:No warning lamps

I had found a leak coming from my 2021 Acura RDX early November. I took it into the dealership December 1st to get it diagnosed and they stated that the transmission and transfer case needs to get replaced. du The problem has been confirmed by the Bloomington Acura dealership on December 1st 2025. After doing research online it looks like this has happened to multiple people with different Acura Models, including newer models of RDX, TLX and MDX. No warning lamps, messages or failures appeared. Just oil leaking beneath the vehicle. It looks like Acura is aware of the issue. The metal shavings from the splines between the transmission and transfer case is destroying the seal. Causing the oil leak hence a new transmission and transfer case.

My car was parked in my driveway. After starting it up and closing my driver’s side door, the entire rear windshield spontaneously shattered without warning or any external manipulation/force. There was no way of knowing of whether or not this would happen. I fear that if I had my dogs in the car (or a child) someone could have been seriously hurt. Shards of glass went everywhere - in the trunk, all over the cargo area, and all over my driveway. I am now stuck without a car while I try to get this repair figured out. Acura/Honda needs to place a recall on this ASAP after seeing how common of an issue it is for many RDX (and other models) owners.

I closed my driver door and the back window just shattered. The glass just exploded.

The transfer case began leaking between the transmission and transfer case. Upon taking it to a mechanic I’ve been told the entire transfer case needs replacement because it has prematurely failed. The repair cost is $5533.00. Through research I’ve seen there are many failing transfer cases on acuras with the SH all wheel drive systems. I believe Acura has a design flaw in the system and should be responsible for the repair.

Rear window spontaneously shattered

Complaint Summary I am filing this complaint regarding American Honda Motor Corp’s handling of a warranty claim on my 2021 Acura RDX. Despite being within the 4-year/50,000-mile warranty, I was denied full coverage for a well-documented defect: condensation/moisture in both headlight housings with no external damage. •Dealer (Rick Case Acura, Sunrise FL) confirmed the condition. •Technician Francisco documented internal moisture, no external damage. •Service Manager Wade Bell submitted goodwill request [XXX], which was approved at 70% only. •My out-of-pocket responsibility was ~$1,400. •I requested full coverage from American Honda, consistent with Acura’s warranty obligations and known issues with these headlight assemblies. On a recorded call, American Honda repeatedly stated my request was denied, refused to provide a written denial, and declined to issue a case reference number directly. Only after reviewing an email did I locate the case number ([XXX]). This refusal to document their denial is highly concerning. ________________________________________ Timeline of Events •[XXX]: Moisture first observed after rain; confirmed by dealer technician. •Dealer Request: Goodwill [XXX] approved at 70%. •Repairs Completed: Both headlights replaced; repair order available. •Sep 2025: American Honda denied my appeal verbally on recorded call; refused written denial. ________________________________________ Manufacturer Guidance Ignored Importantly: American Honda’s own dealer service bulletin (2023) regarding 2019–2021 Acura RDX headlamps explicitly instructs dealers to: •“Create an iN case number (via AcuraLink/Dealer iN) when moisture or condensation is observed inside RDX headlamp housings with no external damage present.” •“Submit for goodwill/warranty replacement of the affected headlamp assemblies.” This vehicle falls squarely within that guidance: a 2021 RDX, <4 years old, <50k miles, with moisture documented by the dealer. Despite this, A INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

While driving over a bump or curb to enter parking lot, I hear a popping noise coming from the sunroof at the front passenger and rear driver side of the car.

The contact owns a 2021 Acura RDX. The contact received notification of NHTSA Campaign Number: 24V064000 (AIR BAGS); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure. Parts distribution disconnect.

At start up, my car displayed 4 errors: Lane Keeping Assist System, Collision Mitigation Braking System, Road Departure Mitigation System, and Electric Power Steering. As a result, my car could not steer and had to get it towed to the dealership.

AcuraLink App was used to attempt to remote start car while at a store, however, the app reported a failed notification and car was never started through the app and only turned on manually. Two hours later, when at home, the car remote started suddenly with no prompt while it was inside of a closed garage. Our dog heard the car go off and alerted us. Had he not heard it, the car would have been running in a closed garage putting us at risk for carbon monoxide poisoning. I have done no other reporting, but I did look this up and found threads online about the same issue and was recommended to report here. There were no other warnings or messages to say that the car turned on.

Drove into parking lot and as I was pulling into the parking spot next to the building, the vehicle started to surge forward as if I had my foot on the gas instead of the brake. The sudden surge caused the vehicle to plow into a brick building causing about $10K damage to the vehicle and $5K to the building. This was not the first time this sudden surging occurred. It happened at least 3 times previously, and one time since. Fortunately, the other occurrences did not lead to any damages, but just some anxious moments. I took the vehicle to the dealership to get checked out after the last occurrence, but they said they couldn't duplicate it. I thought it might be some sort of "unknown" problem, until I started reading on Facebook and other internet websites of other people having the same scary "surging" engine issues. I believe there's more to it now, and an investigation is warranted.

I have a 2021 Acura RDX A-spec AW and ever since I had a brakes problem, when applying brakes will not take break promptly kept slipping like going I address this to the dealer numerous time and what they said is that they haven’t had a recall in order to know what really the problem is I think is due to my calipers and probably rotors, but I think is the cut for defect on these 2021 Acura RDX . Also my engine been leaking oil from the top rear side and rear the valve cover this need to be addressed and I have made a complaint to Acura Honda The Corp. and they said they haven’t been a recall for this. Also, I would like someone to look at this matter break And engine problem due to a leak that could cost a fire.