NHTSA upgrades 2015–2025 Acura and Honda vehicles probe to engineering analysis: No Restart After Auto Start/Stop Engages

Vehicles under investigation

As listed in NHTSA’s investigation file. Not every vehicle of a listed model is necessarily affected.

What ODI says

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.

Official summary by NHTSA’s Office of Defects Investigation for EA25004, quoted in full (U.S. government work, public domain).

What owners have reported

Owners filed 12,695 complaints with NHTSA about the model years in this investigation, reporting 255 crashes, 76 fires, 294 injuries, 3 deaths. These are all complaints on file for those vehicles, about any problem, not only this one; complaints are unverified owner reports.

Recalls and problems for these vehicles

• Acura MDX recalls by model year
  Acura MDX complaints, TSBs and investigations
• Acura TLX recalls by model year
  Acura TLX complaints, TSBs and investigations
• Honda Pilot recalls by model year
  Honda Pilot complaints, TSBs and investigations
• Honda Odyssey recalls by model year
  Honda Odyssey complaints, TSBs and investigations
• Honda Ridgeline recalls by model year
  Honda Ridgeline complaints, TSBs and investigations
• Honda Passport recalls by model year
  Honda Passport complaints, TSBs and investigations

Timeline

1. March 26, 2025ODI opens engineering analysis EA25004
2. OpenNo closing date yet