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.

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

The contact owns a 2019 Acura MDX. The contact stated that while driving at an undisclosed speed, several unknown warning lights illuminated, and the vehicle stalled. The contact was able to drive to the residence after the failure. An independent mechanic was contacted and attributed the failure to the fuel pump. The contact associated the failure with NHTSA Campaign Number: 23V858000 (Fuel System, Gasoline); but the vehicle was repaired under the recall approximately 2 years ago. The contact stated that the failure was caused by an improper recall repair. The dealer was contacted and diagnosed the vehicle with fuel pump failure. The contact was informed that the fuel pump replacement only had a 12-month warranty. The vehicle was not repaired. The manufacturer was not made aware of the failure. The failure mileage was approximately 60,000.

NHTSA ID

11758558

Incident

Aug 11, 2026

Mileage

60,000 mi

The contact owns a 2019 Acura MDX. The contact stated that while driving at various speeds, the driver’s and passenger’s side front seats shifted unexpectedly. The contact stated that there was an abnormal popping sound coming from the center of the seat backrest, which was felt in the seat. The vehicle was not diagnosed or repaired. The dealer was notified of the issue and confirmed that the VIN was not under recall. The manufacturer was not notified of the failure. The failure mileage was approximately 75,000.

NHTSA ID

11757986

Incident

Aug 10, 2026

Mileage

75,000 mi

Car shifted on its own from drive to park right after warning lights stating Electrical Parking System then Emissions the Transmission came on while in stop and go traffic. Car had just come back from Acura mechanic 4 hours earlier as these warning lights had come when starting car. Immediately had car towed to dealership.

NHTSA ID

11752240

Incident

Jun 16, 2026

The subject 2019 Acura MDX model includes the tech package which adds several safety features that function through a windshield mounted camara/radar. The system has malfunctioned and none of the safety features are working. The dash displays the following messages: Collision Mitigation System Problem Adaptive Cruise Control Problem Lane Keeping Asist Problem Road Departure Mitigation System Problem automatic headlight system problem At the bottom of the dash, I see Brake System, Crash Warning and Lane Departure lights on as well. Acura is charging $2,319 to replace this unit in addition to a $270 diagnostic fee. This issue is widely reported as a significant issue in several model years for the MDX and should be part of a safety recall. The Acura technician acknowledged this issue is common. I should add this is the second major electronic issue with this MDX within the last several months. The prior issue was multiple system failure warnings that Acura determined were caused by a faulty wiring harness at a $1,604 cost, plus a $255 diagnostic fee. Please note I am the original owner of the vehicle and it has never been in a collision. Additionally, the system has recently mistakenly activated the brakes at very low speed and warned against collisions with other vehicles traveling in the opposite direction while on a curve.

NHTSA ID

11746803

Incident

Jun 19, 2026

While driving, the vehicle experienced a sudden internal mechanical and electronic transmission failure. Without warning, the vehicle shifted itself directly into Park while navigating the busy intersection of [XXX] and [XXX]. This caused a complete loss of propulsion and left the vehicle entirely immobilized in the middle of a high-speed junction. The vehicle could not be moved, creating an immediate, severe highway safety hazard that required an emergency 911 police response to manage traffic and protect the vehicle from being rear-ended. The dealership scan tool later pulled diagnostic code P0730 (Incorrect Gear Ratio) along with multiple clutch performance failures (P07A4, P07A2, P07A8). INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11746202

Incident

Jun 10, 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.

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.

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

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