2019 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.

The contact owns a 2019 Acura MDX. The contact stated that while the dealer was performing a State Inspection on the vehicle, it was discovered that the front sub frame and control arms were severely corroded and were fractured. The contact received notification of NHTSA Campaign Number: 26V365000 (Structure, Suspension); however, the recall scope was restricted to the rear sub frame and components. The vehicle remained at the dealer. The manufacturer was notified of the failure by phone and referred the contact to the NHTSA hotline for assistance.

NHTSA ID

11775582

Incident

Nov 4, 2026

The contact owns a 2019 Acura MDX. The contact stated that while operating the vehicle, the engine failed to restart after the Auto START/STOP was engaged. The contact stated that while at a stop light, the engine failed to automatically restart after releasing the brake pedal. The contact shifted to park(P) and restarted the vehicle. The contact stated that the failure had occurred on several occasions. Additionally, while the contact’s wife was driving, the vehicle stalled and had to be manually restarted. The local dealer and the manufacturer were notified of the failure. The contact stated that the vehicle had experienced the failure listed in NHTSA Action Number: EA25004 (ENGINE AND ENGINE COOLING). The failure mileage was 90,000.

NHTSA ID

11773910

Incident

Aug 1, 2026

Mileage

90,000 mi

On Saturday 10/24/26 at approximately 6:45 PM I pulled into my garage and pressed the engine button to shutdown the car after parking in my home garage. I was about to open the door and exit when the engine started again. I shutdown the engine once again and safely exited the car with my 13year old daughter. I returned within 15 minutes and attempted to restart the car to examine the dashboard engine lights, it was then I discovered that I was unable to start the car and a warning was displayed on the dashboard that no KEY FOB was present although I was holding it near the start button. I retrieved my spare key fob and attempted to start the engine and noted the same error. The battery on both key fobs had been recently replaced with new batteries. I waited about an hour and attempted to start the engine unsuccessfully once again, the same error displayed "NO KEY FOB present, please place the fob near the start button to engage the engine. I waited approximately 8 hours and was able to restart the engine with no error or issue. This was a very dangerous incident as my daughter and I were in the process of existing the 2019 MDX when the engine started and could have potentially driven through the garage wall.

NHTSA ID

11773721

Incident

Oct 24, 2026

Many customers complained about the LKAS Camera overheating and faulty.

NHTSA ID

11769824

Incident

Aug 10, 2026

Dec. 16, 2025, took Acura into the dealership because Check Engine light kept coming on. They did a full inspection and said I needed to have the purge valve replaced and that it was nearing time to have other services: transmission service, front transfer case, rear differential, brake fluid, timing belt, spark plugs, fuel service. Took the diagnostic to my brother who is a mechanic and he started the work starting with the purge valve. He had already done spark plugs with oil change in Oct. 2026. Fast forward to Apr. 2026 my car starts making a weird knocking sound upon accelerating. My brother was in hospital at this time so I didn't want to stress him so I just stopped driving it. I had the other stuff done at shop he recommended but the knocking sound didn't stop. Brother told me to get it diagnosed again. Now Sept. 2026, they said I need a whole new engine, and that Acura would not cover it! What!? They felt so badly they didn't even charge me for the diagnostic. I took it to two other shops just to see if there was anything else that could be done but they all told me the same thing. It's a 2019 how on earth could it need a new engine. I've gotten ALL the work done that is recommended. I didn't even drive it when it started making that noise. My husband and I have been sharing 1 vehicle! I have not missed an oil change and had all recalls repaired there but the dealership told me since I didn't do the services in the dealership at a premium that Acura would not extend me a Goodwill to replace their faulty engine. Why would I do the work at the dealer when my brother is a mechanic and owns his own shop? I believe my engine is suffering the same issues that are causing millions of Acura owners the same dangerous recall. The last place I took the car was the Acura/Honda Specialists shop in the city where I live and this guy told me everything that was serviced looked good but the car needs a new engine and there's even metal in the oil but my VIN doesn't count!

NHTSA ID

11769561

Incident

Apr 1, 2026

issue occurring with automatic start/stop function. car stalls on occasion trying to restart, goes into neutral, even though battery is new and in good condition. hard to replicate and occurs randomly. car has to be turned off and on again. this is the 4th time this has happened over the course of 3 years. seems to be happening to others based on forums as well.

NHTSA ID

11764975

Incident

Sep 16, 2026

the camera system located above the rear view mirror failed and caused a warning light for the lkas system. adaptive cruise control, lane keeping did not work because of it. the unit had to be replaced. this seems to be a fairly common issue with this mdx version, based on forums

NHTSA ID

11764964

Incident

Aug 6, 2025

Alarm randomly goes off dash lights up on its own and kills the battery Was told it’s the keyless module

NHTSA ID

11764352

Incident

Sep 10, 2026

Service Bulletin - Under certain circumstances, after coming to a stop and the idle stop feature engages, the vehicle may not automatically restart. In other circumstances, vehicles may experience a slow crank or fail to start under hot ambient temperature conditions.

Dealer Message - Under certain circumstances, after coming to a stop and the idle stop feature engages, the vehicle may not automatically restart. In other circumstances, vehicles may experience a slow crank or fail to start under hot ambient temperature conditions. The customer should be able to restart the vehicle by selecting Park and pushing the ENGINE START/STOP button.

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.

Service Bulletin - An uneven sealing surface allows moisture to enter the inner taillight(s), causing one or both of the inner taillights not to work.

Service Bulletin - An uneven sealing surface allows moisture to enter the inner taillight(s), causing one or both of the inner taillights not to work.

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.