2021 Acura RDX: check engine light

Filed Oct 7, 2026 · Engine, Fuel system · TX

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.

Filed Jul 16, 2026 · Acceleration, Brakes · NJ

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)

Filed Mar 5, 2024 · Acceleration, Engine · TN

On 2-10-2024 I was driving the 2021 RDX SH-AWD on I-40W in TN with my daughter in the passenger's seat. It was raining. After about 2 hours of driving, at about 3:00 pm, I took a break at a Rest Area near Buffalo Valley. After ~20-min rest, I restarted the car and tried to merge back onto I-40W. I was accelerating towards the speed limit of 70 m/h, but suddenly, at about 65m/h, I felt the car losing power. I could not speed up anymore: the car did not respond to the gas pedal and the speed dropped to about 40m/h. The orange engine light started to flash on the dashboard. A truck nearly piled on me from behind. Cars and trucks from behind had to switch lanes quickly to avoid collision. I was able to pull over to the shoulder and stopped with my emergency light on. I turned off the engine for about 10 minutes, then I restarted the car again and got back on the road. This time, everything seemed normal, but I was so scared and worried the car might suddenly not respond again. Fortunately, I was able to get home eventually without any additional problems.

Filed Dec 29, 2022 · Acceleration, Engine · PA

On 12/22/22, I was driving in a 2021 RDX SH-AWD with my pregnant wife and 2 year old son from Media PA to Pittsburgh PA . It was rainy and 35-40 degrees F the whole drive. Approximately 4 hours into the drive we stopped at a rest stop on the PA turnpike to get gas. While attempting to merge back onto the turnpike from the service road to the right of the turnpike, a truck was coming up behind me in the right hand lane of the turnpike. I was traveling approximately 40mph on the service road, so I went to accelerate to safely complete the merge in front of the truck. Near the end of my acceleration sequence (I estimate I had gotten to approx 65mph) my car went into “limp mode”. I felt an unexpected and immediate loss of power and my check engine light/“MIL” began flashing yellow. I was luckily able to barely avoid a collision with the truck that was approaching. After the light started flashing I was unable to turn the knob to switch drive modes (it was in snow mode at the time this all happened). I was unable to do anything but attempt to drive to safety with severe power loss. I was able to coast my car with minimal accelerator response to the next exit off the turnpike and into a motel parking lot. I shut down the car and then turned it back on. When I turned it back on, the MIL light was no longer flashing and I had normal power restored to the vehicle, but interestingly the auto stop/start feature no longer worked. I was able to drive the remainder of the way to Pittsburgh without any further loss in power, though I was anxious the entire drive considering the major malfunction I had just experienced while attempting a merge at highway speeds. The vehicle only had approx 10,500 miles on it at the time of the incident. The vehicle is currently at the dealership being diagnosed. A case has also been opened directly with Acura/Honda.

Filed Sep 13, 2022 · Engine, Transmission · VA

I was accelerating up a hill on a WV highway in a steady rain, the engine cut power, the check engine light flashed on and off, further throttle input did nothing, the car slowed on its own. I had to pull over from the left lane dangerously cutting in front of vehicles in the right lane as I could no longer maintain highway speed. Shut the car down and waited to rekey. Vehicle has operated fine ever since. The dealer has not been able to duplicated the issue (two weeks afterwards)

Filed Apr 5, 2022 · Engine · NY

during acceleration on highway to pass a vehicle the Acura RDX lost power and decelerated. Check engine light came on....engine lost power to accelerate/maintain highway speed almost causing an accident.

Filed Sep 23, 2021 · Acceleration, Engine · IN

I own a 2021 Acura RDX that was purchased new in February 2021. In the 11,500 miles I have driven it, there have been zero problems until yesterday. However, yesterday, when driving on an Interstate highway at 70 mph, in the rain, while passing a semi truck, my Acura RDX suddenly went into limp mode and the check engine light began flashing. After pulling over to the berm, and driving in the limp mode to the next exit, I turned the engine off. When I turned the engine back on it functioned normally and the check engine light went out. The engine has functioned normally for the approximately 100 miles I have driven since that time. Since there is no problem now, I have not taken the vehicle to the dealer to be checked since I felt that they would find nothing. When looking up this problem I found that mine is not an isolated case, and this same thing has happened to other Acura RDX owners. For that reason I am reporting the problem. I have also written to Acura to tell them of the problem. This was a very scary situation to have the engine suddenly, and without warning, go into limp mode while on a busy Interstate highway. Fortunately, in this case I was able to safely get to the berm of the road, but that might not always be possible. I have no idea when this might happen again, which is also scary. It is also very strange that by turning the engine off and then back on the problem disappeared. If requested, I would be happy to have Acura look at my vehicle if it would help to find the root cause of this problem. Thank you for your review of this problem.

Filed Aug 20, 2021 · Engine, Transmission · NJ

Driving at night in rain on interstate 81N in southern Virginia. I pressed accelerator all the way to pass and the car downshifted and then lost power. The engine light was flashing. I did not have enough power to maintain adequate highway speed while in the midst of a passing maneuver. While car was decelerating (with foot on accel pedal with no apparent response) I activated hazard lights and made my way across traffic to the shoulder. 70mph speed limit. I dropped to 50mph or so rather quickly amid traffic that put me and the traffic around me in a dangerous situation. Once stopped on shoulder (again in a dangerous situation that I'd prefer to avoid), i turned ignition off for 10 seconds and then restarted car. Situation seems to have cleared up; no engine light flashing and full? power. It did not happen again when I pressed accelerator to floor to recreate situation. This vehicle has 3800 miles on it.

Filed Jul 24, 2021 · Engine · FL

Incident happened on, 22 July 2021- Rainy day, accelerated vehicle to pass, vehicle went limb unresponsive, check engine blinking, needed to stop in Highway 4. Almost got rear-ended by semi trailer, fortunately made maneuver for emergency stop. Turned vehicle off for a few minutes, while my heart settled and turned vehicle back on check engine was no longer blinking and vehicle was once more responsive. 24 July 2021, I am currently in Acura Autonation Dealer in Sanford for maintenance appointment and informed them of issue. I am waiting for their system to come up since they are currently having issues, hopefully I will receive further info on malfunction of vehicle.

Filed Jun 22, 2021 · Engine, Transmission · TX

Brand new 2021 RDX - bought 3 days ago, only 128 miles. Driving on highway and it suddenly loses power. Was able to get to shoulder, but unable to get enough power to exit the highway to find a safer place to park. Check engine light and several transmission warnings indicating I should see dealer immediately. As vehicle came close to a stop, it shuddered and clunked so badly it seemed like I ran something over, but nothing was there. Tried to shut vehicle down and restart, but constant error messages and would only lurch a little. Had to have vehicle towed to dealership, but of course they said they never heard of this happening before.

Filed Jun 11, 2021 · Engine · MD

I was driving in the rain, accelerated to pass a vehicle and the engine lost power. The check engine light came on and the car went into "limp" mode. The car would barely go 40 mph on a highway and the speed seemed to be continuing to decrease. Luckily I was able to pull over and shut the car off. Restarted, the problem appeared to go away. This is a very dangerous situation and I have read other people reporting similar incidents.

Filed May 24, 2021 · Engine · OR

2021 RDX A-spec 7322 miles northbound Hwy 95 Nevada to Oregon, raining. Attempted to pass semi, car behind me also passing semi, sudden loss of power, almost hit from behind, risk of on-coming traffic, able to move to right behind semi. Feeble response to any attempt to accelerate, barely limping along, moved to right shoulder and then to pullout, blinking check engine light, no other warning indicators. Idled engine for several minutes, continued to run rough, would not rev, check engine light cycled off, then back on (blinking), then off over period of several minutes. Turned engine off, waited 10 min or so, restarted ok, finished rest of 600 mile journey scared to pass lawnmower. Life-threatening event for my wife and I, several moments of sheer panic. First time this has happened.