2020 Acura MDX

The Office of Defects Investigation (ODI) has received 414 reports of connecting rod bearing failures in the 3.5L V6 engine used in the following vehicles: Model Years (MY) 2018-2020 Acura TLX, MY2016-2020 Acura MDX, MY2016-2020 Honda Pilot, MY2018-2020 Honda Odyssey, and MY2017-2019 Honda Ridgeline.  The subject engine failures were analyzed as part of a Recall Query (RQ24013).  It was determined that these engine failures are outside the scope of Honda Recall 23V-751. Further, evidence gathered in conjunction with RQ24013 does not suggest this failure is caused by the same crankshaft manufacturing defect that is addressed by Honda in Recall 23V-751.  Based on analysis of data from RQ24013, NHTSA has closed that investigation. The significant number of reports of engine failure in vehicles outside the scope of RQ24013 presents a potential safety risk that warrants further investigation.  ODI is opening this Preliminary Evaluation (PE) to further evaluate the scope and severity of the potential problem and to fully assess the potential safety-related issues.  To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to NHTSA.gov.

On June 3, 2022, the Office of Defects Investigation (ODI) opened Preliminary Evaluation PE22005 after the agency received VOQs and several field reports concerning the Auto Idle Stop (AIS) feature on 2016-2019MY Honda Pilot vehicles. The complaints allege that the engine fails to restart on its own from a complete stop at a traffic light or road intersection with the AIS function engaged. The subject vehicles are equipped with a 3.5L engine with a 9-speed automatic transmission. On January 6, 2023, Honda released service bulletins 23-008 and 23-009. These service bulletins address the failure to restart issue in the 2016-2019MY Honda Pilot vehicles, as well as the 2015-2020 Acura TLX, 2016-2020 Acura MDX, 2019-2022 Honda Passport, and 2020-2023 Honda Ridgeline vehicles. The repair outlined in the service bulletins is a two-stage countermeasure to remedy the issue. The first stage is a Programmed Fuel Injection (“PGM-FI”) software update. The second stage is only deployed if the software update fails to remedy the issue. The second stage, depending on the model and model year, consists of replacement of the starter assembly, starter relays, and a valve adjustment. Additionally, Honda extended the warranty coverage to 10 years with unlimited mileage for vehicles requiring the second stage component replacement. ODI continues to receive complaints of the AIS failure to restart, with many complainants alleging the campaign countermeasures had been completed.NHTSA has reviewed Honda's Information Request Letter responses involving warranty claims, lawsuits, and consumer complaints in addition to ODI's own data. This Engineering Analysis is being opened to further consider the potential safety defect, including gathering additional data regarding Honda’s service campaign efficacy. ODI is additionally expanding the scope to encompass all vehicles addressed in Honda’s service bulletins 23-008 and 23-009 as well as newer model year vehicles, which are substantially similar to the vehicles covered by the service campaign. To review the ODI reports cited in the Opening Resume ODI Report Identification Number document, go to NHTSA.gov.

On November 8, 2024, the Office of Defects Investigation (ODI) opened Recall Query RQ24013 to assess the scope of Honda recall 23V-751 after receiving complaints that alleged connecting rod bearing failures in vehicles that were not within the scope of recall 23V-751. In November 2023, Honda recalled 248,999 various Model Year (MY)2016–2020 Honda and Acura vehicles equipped with the 3.5L V6 engine. Honda recalled these vehicles due to a crankshaft manufacturing defect that caused premature connecting rod bearing wear and engine seizure. While the out-of-scope failures involved in these complaints appear to have a very similar failure mechanism as the recalled engines, a thorough analysis of all available data from Honda has not indicated that the same manufacturing defect exists in the out-of-scope engines as the engines recalled by 23V-751. Based on this analysis ODI has determined that Honda has properly defined the scope of recall 23V-751. Consequently, ODI will close this RQ investigation.  NHTSA will continue to investigate these complaints of engine failure as part of a new Preliminary Evaluation Investigation (PE25008). The Agency reserves the right to take additional action if warranted by new circumstances.

A federal safety recall was performed on the vehicle to install a rear subframe reinforcement kit. Before the recall repair, the vehicle operated normally and had no vibration at highway speeds. Immediately after the recall repair, a new vibration developed above approximately 60 mph. The vibration is felt primarily from the rear of the vehicle, occurs only while accelerating, becomes most noticeable between 60 and 80 mph, and disappears immediately when the accelerator is released while maintaining the same speed. The condition is repeatable and remains unresolved. The vibration creates concern for loss of vehicle stability and control at highway speeds because it occurs while the drivetrain is under load. No warning lights or diagnostic messages appeared before or after the repair. The vehicle has been inspected by both the dealership that performed the recall repair and an independent repair facility. To eliminate other possible causes, the front hub and bearing assembly were replaced and all four tires were remounted and dynamically balanced. Those repairs did not eliminate the rear vibration. The dealership attributed the condition to unrelated maintenance items, including tires, wheels, and brakes, but did not identify a defect with the recall repair or determine whether the rear subframe installation, rear differential mounting, driveshaft, or other components disturbed during the recall procedure contributed to the new vibration. The timing of the failure is significant because the vibration began immediately after completion of the federal recall repair and was not present beforehand. The component is available for inspection upon request. I am requesting that NHTSA investigate whether the recall remedy or repair procedure may have introduced a drivetrain or rear suspension condition affecting vehicle safety.

NHTSA ID

11750239

Incident

Jun 26, 2026

The car had several warnings lights come on and immediately stalled out and stoped right in the middle of the road. The engine would turn over but would sputter like it was out of gas and would die after a few seconds. It stoped in the middle of a busy state highway in a curve. Luckily no one got hurt. I towed it to an auto service center. The 2020 Acura MDX suffered an in-tank fuel pump failure causing a low fuel pressure code (P0087). This model year is under a massive 2.6-million vehicle safety recall, but my specific VIN was omitted. It likely should be included before someone gets hurt.

NHTSA ID

11749098

Incident

Jul 6, 2026

See attached document for complaint.

NHTSA ID

11747720

Incident

May 14, 2026

The contact owns a 2020 Acura MDX. The contact stated that while driving approximately 20 - 25 MPH, there was an abnormal knocking sound coming from the passenger’s side of the vehicle. The contact stated that the check engine warning light and other unknown warning lights were illuminated. The vehicle stalled and was towed to dealer to be diagnosed. The dealer determined that the engine had seized. The contact associated the failure with NHTSA Campaign Number: 23V751000 (Engine and Engine Cooling); however, the VIN was not included. The manufacturer was made aware of the failure. The failure mileage was approximately 104,000.

NHTSA ID

11746661

Incident

May 9, 2026

Mileage

104,000 mi

Collision Mitigation, Automatic Cruise Control, and Lane Keep Assist features disabled. Safety equipment failure.

NHTSA ID

11746074

Incident

Jun 18, 2026

Good morning, Out of nowhere my dashboard lit up after 5+ years of having no issues with the vehicle. I believe there are a total of 5 safety features that are linked to the ADAS camera in this MDX but i am not 100%, it may be 4 safety features. I am not here to whine about a repair on a 6 year old vehicle but this particular issue has become extremely common with this vehicle. I believe (along with all the other owners) that the ADAS issue with certain year Acura & Honda is happening way to often way too soon. my MDX does not even have 70k on it! after doing some research between Facebook, Reddit & many other Acura/Honda forums this appears to be all too common. when that camera shits the bed you lose many of the main safety features that may have brought you to purchase that vehicle. My local Acura dealer in Wilmington, NC told me he is replacing this part once a month and none of them are under warranty I'm not sure why he shared that with me but he did. that is an alarming number considering where i live and how few MDX's there probably are in my area. Where i live everyone drives either a full size pickup or suv and theyre all American brands. the dealer wants $1800 for the repair. I'm getting it done because i have the money to do it but I am not happy at all. normal wear and tear repairs i get, this one however i have a major issue with it. many people are not having the repair done because the car is driveable. any help with this would be greatly appreciated & thank you for your time. [XXX] [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11741211

Incident

May 1, 2026

My cruise control, automatic lane changing indicator light indicator, brake indicator light, high beam light indicator lights all keep coming off and on. Researching it on YouTube states that it’s the camera on my windshield getting too hot and it’s a known issue. It’s $1800 To fix but others have stated they get fixed and it doesn’t resolve the problem. Asking for your help.

NHTSA ID

11741032

Incident

May 29, 2026

While sitting stopped at a red light, the brake pedal suddenly became soft and the vehicle began moving. As I rushed to depress the pedal further (all the way to the floorboard - which did not stop the car) the car rolled forward and collided with the car in front of us causing damage to both vehicles. If the other car had not been in front of us we would have rolled directly into heavy active cross traffic which would have caused significant harm to all inside. My daughter, niece, and 8 month old grand-niece were with me in the car.

NHTSA ID

11740691

Incident

May 25, 2026

Owner Notification Letter - Under certain circumstances, after coming to a stop and the idle stop feature engaging, the vehicle may not automatically restart. Acura is providing a product update with a new PGM-FI software update to fix this issue.

Dealer Message - Under certain circumstances, after coming to a stop and the idle stop feature engages, the vehicle may not automatically restart. Typically, the client can immediately restart the vehicle by selecting Park and pushing the ENGINE START/STOP button.

Service Bulletin - Under certain circumstances, after coming to a stop and engaging idle stop the vehicle may not restart automatically due to excessive cylinder pressure and/or low cranking torque. Typically, the client can immediately restart the vehicle by selecting Park and pressing the ENGINE START/STOP button.

Service Bulletin - The AWD warning light is on with one or more AWD DTCs having been set due to water intrusion into the electric oil pump motor connector area corrodes the terminals.

Service Bulletin - The AWD warning light is on potentially due to water intrusion into the rear differential pump motor connector area that corrodes the terminals.

Service Bulletin - Client complaint of A/C not blowing cold air due to oil/refrigerant leak from the A/C compressor shaft seal.