2018 Acura Rlx

The Office of Defects Investigation (ODI) opened this investigation to determine if the failure of airbags to deploy during severe crashes, in certain vehicles, was the result of a safety related defect.  During the investigation a complex failure was studied that can result in non-deployment of subject vehicle air bags and other restraint system devices in severe crash events. The subject vehicles may be equipped with an airbag control unit (ACU) for the supplemental restraint system (SRS) Electronic Control Unit (ECU) manufactured by ZF-TRW.  The ECU receives signals from crash sensors mounted in the vehicle and deploys the vehicle air bags and seat belt pretensioners in accordance with manufacturer design specifications.  The ECU in the subject vehicles contains a model DS84 application-specific integrated circuit (ASIC) which controls the communication of the crash sensor signal, firing commands (i.e., when to deploy the airbag(s) and/or pretensioners), and fault information (e.g., diagnostic trouble codes). In September 2016, FCA announced recall 16V-668 for certain model year (MY) 2010 to 2014 Chrysler, Dodge and Jeep products manufactured with the subject ZF-TRW ACU.  In this recall, FCA discussed an EOS condition that resulted in a failure of the subject DS84 ASIC, which caused air bag non-deployment.  FCA noted that the defect condition had only been observed in vehicles equipped with sensor harnessing routed across the front of the vehicle.  Other FCA vehicles that also used the subject ACU, but were not equipped with cross-car harnessing, had not experienced EOS failures, despite similar time in service. During the course of this investigation, ODI sent two separate Information Request (IR) letters to six vehicle manufactures (including FCA, Hyundai, Honda, Kia, Mitsubishi, and Toyota) and one IR letter to ZF-TRW.  These IR letters resulted in ODI receiving comprehensive data from these manufacturers and suppliers. Studies of this data found that the DS84 ASIC does not have sufficient protection against negative electrical transients or electrical overstress (“EOS”) that can be generated in certain severe crashes.  An electrical transient occurs when the electrical power supplied to a circuit changes momentarily over a short duration of time.   In these severe crash cases, the crash sensors and other powered wiring can be damaged and short circuited so as to create a negative electrical transient of sufficient intensity and duration (that are outside the vehicle manufacturer's specification) to damage the ASIC before the restraint device deployment signal is received by the SRS ECU.  This damaged signal can lead to incomplete or nondeployment of the air bags and/or pretensioners.  Airbag non-deployment and/or lack of pretensioner operation can increase the risk or severity of injury in a crash.A total of 8 fatalities and 14 injuries were associated with known EOS events. The common element in all investigated manufacturers vehicles is the SRS ECU containing a DS84 ASIC manufactured by ZF-TRW.  The risk associated with the ASIC is equally shared among all OEMS involved in the investigation.  The actual real-world risk can be mitigated by other factors which were assessed by ODI during this investigation. The first mitigating factor involves protections built into the ACU design which protect the DS84 ASIC from damage.  There are multiple strategies and levels of protection employed by different OEMs that provide effective EOS mitigation.  The two most common strategies at the ACU level are circuit protection diodes on the remote senor signal lines, and current limiting resistors that protect critical components. The second mitigating factor is found at the vehicle level and involves the location and routing of the wires leading from the crash sensors to the SRS ECU.  If the wires are well protected in a crash and are not routed with other power wires carrying large currents, the risk for an EOS event is significantly reduced or eliminated. These design specific factors combine to produce a spectrum of risk for the vehicles equipped with ACUs using the DS84 ASIC.  Given the many of years of field exposure, it is possible to divide the subject population into two groups; vehicles which have experienced EOS events, and vehicles which have not experienced EOS field events. Four of the six OEMs involved in this investigation have experienced EOS field events on at least one of their models equipped with a DS84 ASIC.  All vehicle models (including the Toyota models identified in the Failure Report Summary of the opening resume for this investigation) with field events have been recalled.  In an abundance of caution, ODI kept this investigation open five years to monitor field performance and did not identify any field events on vehicles not included in existing safety recalls. Given the spectrum of risk identified in this investigation and that all vehicles with a demonstrated unreasonable risk have been recalled, ODI is closing this investigation. ODI is closing this investigation with the following manufacturer safety recalls: 16V-668, 18E-043, 18V-137, 18V-363, and 20V-024.  With the recall actions taken by the subject vehicle and equipment manufacturers, this investigation is closed. The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exists on other model or model year vehicles outside of the recall scopes. The agency reserves the right to take further action if warranted by the circumstances.

The first time I heard the engine noise was on [XXX]. I brought the vehicle to the Schaumburg Muller Acura dealership and dropped it off on May 20. On May 21, the dealership performed an initial inspection and informed me that they needed authorization to further disassemble the engine in order to determine the cause of the problem. I provided that authorization, and by May 22 the engine had been torn down to the point where the failure could be identified. On May 22, I spoke with my service advisor, Ken, who informed me that the connecting rod bearings were worn and that the engine would need to be replaced. I was sent photographs, a video, and an estimate for the repair totaling $12,943.83. While I was shocked by the cost, Ken advised me that the dealership would be contacting Acura to request goodwill assistance on my behalf. Because this occurred immediately before the Memorial Day weekend, several days passed before I received an update. On May 30, a different service advisor informed me that Acura had approved $8,000 in goodwill assistance. During that conversation, he asked me, “The original estimate was around $16,000, right?” I knew that was incorrect, as the estimate I had received was $12,943.83. Concerned by the discrepancy, I contacted Acura Customer Relations on June 1 and opened a case for review. Later that same day, I spoke with Ken and provided him with the case number. During that conversation, he informed me that the original estimate had been incorrect because certain parts and/or labor had allegedly been omitted. I was then told that the actual repair cost would be approximately $18,000 to $19,000 plus tax. While I can understand minor adjustments to an estimate, a difference of several hundred dollars or even $1,000 might be reasonable. However, an increase of approximately $6,000 from the original estimate is extremely concerning and raises serious questions about the accuracy of the repair assessment and cost estimate. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (

NHTSA ID

11741672

Incident

May 20, 2026

The contact owns a 2018 Acura RLX. The contact stated while driving her vehicle at an undisclosed speed, stated that the vehicle would not start up, and noticed every single waring light illuminated up on her dash. The vehicle was taken to a dealer twice, first time it was diagnosed to have a crank sensor failure, it was replaced. Two days after, the issues reoccurred, where it was diagnosed to be the engine starter. The vehicle was repaired. The manufacturer was notified of the failure. The failure mileage was 51,000.

NHTSA ID

11738529

Incident

Dec 1, 2025

Mileage

51,000 mi

The contact owns a 2018 Acura RLX. The contact stated that while attempting to start the vehicle, the headlight failure message was displayed. A dealer was contacted. The vehicle was taken to the dealer, where it was diagnosed that the A/C compressor needed to be replaced. The vehicle was not repaired. The contact stated that the failure started occurring in 2023. The manufacturer was notified of the failure and informed the contact that, because she was not the first owner, assistance was denied. The approximate failure mileage was 110,785.

NHTSA ID

11722582

Incident

Mar 15, 2023

Mileage

110,785 mi

The contact owns a 2018 Acura RLX. The contact stated while driving 30 MPH, the oil change and tire rotation messages were displayed. The contact stated that a dealer was contacted. The contact stated that an oil change and tire rotation were performed, and the contact was informed that the engine was knocking. The contact received a call notification from the dealer two days after the vehicle was repaired regarding the connecting rod bearing. The contact was informed that the engine needed to be replaced. The vehicle was not repaired. The contact stated that the VIN was not included in NHTSA Campaign Number: 23V751000 (ENGINE AND ENGINE COOLING). The manufacturer was notified of the failure and stated that the issue would be escalated to a higher department. The failure mileage was 92,000.

NHTSA ID

11642306

Incident

Feb 8, 2025

Mileage

92,000 mi

The contact owns a 2018 Acura RLX. The contact received notification of NHTSA Campaign Number: 23V858000 (Fuel System, Gasoline); 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.

NHTSA ID

11628568

Incident

Dec 3, 2024

My vehicle has the same 3.5 liter naturally aspirated V6 that comes in the Acrua MDX which is currently on recall for connecting rod bearings on vehicles with 3.5-liter V6 engines can fail, leading to complete engine failure. my car has the excact same engin with the exact same problem. i have the full diagnosis and estimate from Acura ENGINE REPLACEMENT

NHTSA ID

11624761

Incident

Oct 28, 2024

Warranty Extension - Under certain circumstances, abnormal noise may be heard from the rear when driving straight or making small side-to-side turning movements with the steering wheel. The P-AWS indicator or warning light may also illuminate with certain diagnostic trouble codes.

Owner Notification Letter - Under certain circumstances, abnormal noise may be heard from the rear when driving straight or making small side-to-side turning movements with the steering wheel. The MIL may also illuminate with certain DTC codes.

Dealer Message - Due to manufacturing errors, abnormal noise may be heard from the rear when driving straight or making small side-to-side turning movements with the steering wheel. The MIL may also illuminate with DTC C1600-94 (PAWS unexpected behavior) and/or C1611-13/C1621-13 (PAWS actuator disconnection L&R).

Service Bulletin - Due to manufacturing errors, abnormal noise may be heard from the rear when driving straight or making small side-toside turning movements with the steering wheel. The MIL may also illuminate with DTC C1600-94 (PAWS unexpected behavior) and/or C1611-13/C1621-13 (PAWS actuator disconnection L&R).

American Honda Motor Co., Inc. (AHM) is searching for certain 2016-2020 MDXs, RLXs & TLXs with a client complaint of the Malfunction Indicator Light (MIL) on with the DTC P030X (Cylinder Misfire Detected), P0171 & P0174 (Rear/Front Bank Fuel System Too Lean), or P219A&B (Air-Fuel Ratio Variation of Cylinder) stored. To better understand the cause of this condition, AHM would like to collect specific parts from the vehicle prior to you attempting a repair of any kind.

Service Bulletin - The timing belt area chirps after the engine warms up.