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2015 Subaru Legacy

Owner reports · Recalls · Investigations

More warning signs than most Legacy years

Owner complaints for the 2015 Subaru Legacy are substantially higher than the model-year median of 77.

About this comparison →

When problems were reported

Mileage at the reported incident

104 reports with mileage · 55 unknown

NHTSA’s mileage field refers to the reported incident, not necessarily the filing date. This shows report counts, not the likelihood of a failure.

What to inspect

Issues worth paying extra attention to based on owner reports.

  • Electrical System. Review the 37 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Visibility/wiper. Review the 36 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Engine. Review the 23 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →

NHTSA owner reports · September 18, 2026 snapshot.

15 crash reports3 fire reports7 injury reports

What owners actually said

159 reports
Mileage unknown · Mar 10, 2026
Power Train

2015 Subaru Legacy 2.5i, approximately 48,000 miles. CVT transmission failed suddenly with no prior warning signs. Vehicle was exclusively dealer-serviced for its entire life. While driving, the transmission began shuddering, slipping, and making metallic grinding noises. Vehicle could barely climb a small ramp and was locked in…

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2015 Subaru Legacy 2.5i, approximately 48,000 miles. CVT transmission failed suddenly with no prior warning signs. Vehicle was exclusively dealer-serviced for its entire life. While driving, the transmission began shuddering, slipping, and making metallic grinding noises. Vehicle could barely climb a small ramp and was locked in limp mode, making it unsafe to operate in traffic. Diagnostic codes P0841, P0700, and C1431 were stored. Authorized Subaru dealer confirmed the failure. Technician stated the valve body likely failed first — a known defect per Subaru TSB 16-107-17R — which then caused the CVT chain to slip. Dealer quoted $11,000 for a remanufactured CVT replacement. Service representative stated she had never seen a transmission need replacement at such low mileage. No warning lamps or symptoms existed prior to sudden onset. CVT fluid was never changed, consistent with the manufacturer's U.S. maintenance schedule. This vehicle falls under Subaru's CVT Warranty Extension covering 2010-2015 Legacy models due to known defects. Vehicle is well under the 100,000-mile limit but approximately 13 months past the 10-year time limit. I opened a case with Subaru of America Customer Advocacy. My dealer informed me that Subaru Corporate contacted them and communicated a decision regarding my case, but Subaru has never communicated any decision to me directly. Multiple emails, a voicemail, and a request for escalation have gone unanswered over several days. This failure poses a safety risk as the transmission can fail suddenly and without warning while in motion, potentially with passengers including children.

NHTSA ODI #11723218

Mileage unknown · Feb 27, 2026
EngineForward Collision AvoidanceFuel/propulsion SystemCrashInjury

I am reporting a Sudden Unintended Deceleration event in my Subaru. The vehicle grinded to a halt without driver input. The car stopped in the left lane of a major highway. We put on our hazards and called the state police for help. They were unable to get to us in time. We were hit from the rear. The car's failure created…

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I am reporting a Sudden Unintended Deceleration event in my Subaru. The vehicle grinded to a halt without driver input. The car stopped in the left lane of a major highway. We put on our hazards and called the state police for help. They were unable to get to us in time. We were hit from the rear. The car's failure created a stationary hazard that led to a high-speed rear-end collision by a Jeep and truck which caused the car to do a 360-degree spin.

NHTSA ODI #11721080

Mileage unknown · Jan 31, 2026
EngineService BrakesUnknown Or Other

Incident ~ 5:40 pm, Geneva NY Weather ~ 10 F, not snowing. Background. On or shortly after being started, the vehicle had exhibited prior incidents of extremely rapid engine acceleration not initiated by the operator. Most recently the day before. The incident: I was in the process of very slowly parking the vehicle in a narro…

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Incident ~ 5:40 pm, Geneva NY Weather ~ 10 F, not snowing. Background. On or shortly after being started, the vehicle had exhibited prior incidents of extremely rapid engine acceleration not initiated by the operator. Most recently the day before. The incident: I was in the process of very slowly parking the vehicle in a narrow laneway, and positioning the vehicle behind and in line of one other, both parallel to the laneway, in a small area that had been cleared of snow, leaving the laneway open. First, I stopped the vehicle opposite of the parked vehicle's driver side door. Second, I reversed and backed up and positioned the vehicle behind that vehicle. This involved firmly stepping on the brake to stop the vehicle once well behind the parked vehicle. Third, while keeping my foot firmly pressed on the brake pedal, I moved the shift from reverse to forward. At that time, the front wheels were still fully turned to the left. Immediately on completing the shift to forward, my vehicle made a very rapid acceleration. My foot had remained firmly on the brake and had not touched the accelerator pedal. Despite my foot being firmly pressed on the brake pedal, my car surged forward, retracing the path that I had followed while backing up. I could hear the noise of the accelerated engine, and feel the fighting of the brake as the car surged uncontrolled for about four feet and then finally stopped. My foot had been fully depressed as hard as possible on the brake the entire time and did not touch the gas pedal at all. The owner of the parked vehicle observed the incident and expressed concern since the surge was dramatic, and stopped with the right corner of the front bumper of my car within a couple of inches of the left corner of the parked vehicle. The driver's car mat was in the correct position and did not interfere in any way with the operation of the vehicle. I did not inadvertently step on the accelerator. No warning lamps or messages. Cause Unknown.

NHTSA ODI #11714652

135,000 miles · Nov 21, 2024
Air Bags

The contact owns a 2015 Subaru Legacy. The contact stated while reversing into the driveway, the driver's side air bag unintendedly deployed. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. The vehicle was scheduled to be towed to the local dealer. The manufacturer was made aware of the failu…

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The contact owns a 2015 Subaru Legacy. The contact stated while reversing into the driveway, the driver's side air bag unintendedly deployed. The vehicle was not diagnosed or repaired by an independent mechanic or the dealer. The vehicle was scheduled to be towed to the local dealer. The manufacturer was made aware of the failure. The contact was advised to have the vehicle towed to the local dealer for diagnostic testing. The failure mileage was approximately 135,000.

NHTSA ODI #11626620

175,000 miles · Sep 23, 2024
Power TrainService Brakes, Hydraulic

The contact owned a 2015 Subaru Legacy. The contact stated that while the vehicle was parked, the contact opened and closed the trunk, triggering the alarm system. The alarm system failed to deactivate immediately. The vehicle then failed to restart as needed, and the "Shift to Park" message was displayed while the transmission …

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The contact owned a 2015 Subaru Legacy. The contact stated that while the vehicle was parked, the contact opened and closed the trunk, triggering the alarm system. The alarm system failed to deactivate immediately. The vehicle then failed to restart as needed, and the "Shift to Park" message was displayed while the transmission was in park(P). The vehicle was towed to the dealer, where the brake fuse was replaced; however, the failure persisted. The contact replaced the brake fuse for a second time, but the failure recurred. The vehicle was towed back to the dealer, where an unknown repair was performed. The contact later sold the vehicle. The manufacturer was not made aware of the failure. The failure mileage was approximately 175,000.

NHTSA ODI #11615990

Mileage unknown · Sep 10, 2024
Fuel/propulsion System

2015 Subaru Legacy 2.5 engine. Fuel gauge is inaccurate. My daughter was on the highway when it ran out of fuel. Had car towed to a independent shop. They said that the fuel gauges is a problem for Subaru 's and that they had seen it before on other Subaru's.

NHTSA ODI #11613803

76,000 miles · Jun 27, 2024
Visibility

The contact owns a 2015 Subaru Legacy. The contact stated that while the vehicle was turned off on two occasions, the contact observed three cracks in the top-middle of the windshield that led to an 'S' shape crack in the middle of the windshield. The vehicle was taken to an auto body and glass shop where it was diagnosed that t…

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The contact owns a 2015 Subaru Legacy. The contact stated that while the vehicle was turned off on two occasions, the contact observed three cracks in the top-middle of the windshield that led to an 'S' shape crack in the middle of the windshield. The vehicle was taken to an auto body and glass shop where it was diagnosed that the lament had pulled away from the glass and the windshield needed to be replaced. The vehicle was repaired but the failure recurred three weeks later. The manufacturer was not notified of the failure. The failure mileage was approximately 76,000.

NHTSA ODI #11597183

Mileage unknown · May 29, 2024
Vehicle Speed ControlCrash

Subaru sudden acceleration – Garage Accident [XXX] [XXX] – before noon, wet, rainy day: [XXX] returning from grocery shopping - car suddenly accelerated from near stop as she was about to enter garage, the car hit the garage brick wall. When she put her foot on the brake, the car suddenly accelerated. I have security video sho…

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Subaru sudden acceleration – Garage Accident [XXX] [XXX] – before noon, wet, rainy day: [XXX] returning from grocery shopping - car suddenly accelerated from near stop as she was about to enter garage, the car hit the garage brick wall. When she put her foot on the brake, the car suddenly accelerated. I have security video showing this sudden acceleration (.mp4, nhtsa doesn't accept). After accident, car drives well - all lights work - hood opens and locks. Substantial car damage to bumper and adjoining parts - wood trim damaged, garage bricks cracked and pushed in, garage door would not close. [XXX] Wed – took Subaru in for unexpected sudden acceleration on braking – [XXX] – test drive with Gary – Problem unexpected with Subarus – electronic control – no manual linkage (some transmission linkage with shift lever). Sent me home – no charge. [XXX] – Subaru sudden acceleration on braking while car cold – today at Trexlertown after haircut. Happened previously within week. Called Subaru 855-399-3787; INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI #11591225

Mileage unknown · Apr 15, 2024
EngineSuspensionUnknown Or Other

Took it for inspection was told the part that holds the engine up is rotting away and it will not pass inspection next year this is disappointing I have cars older then this and they are in better condition this vehicle was brought brand new this should not occur I could understand if it was old this car is only 8yrs old I have …

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Took it for inspection was told the part that holds the engine up is rotting away and it will not pass inspection next year this is disappointing I have cars older then this and they are in better condition this vehicle was brought brand new this should not occur I could understand if it was old this car is only 8yrs old I have pics to support

NHTSA ODI #11583015

Mileage unknown · Apr 9, 2024
Electrical SystemSeats

I have had several battery issues that I just believed to be bad luck and would get a new battery under warranty but it has gotten worse lately. It led me to look online and I notice I am not nearly the only one as this complaint has been brought up my numerous people. It is in regards to my 2015 Subaru legacy and how I’m not ce…

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I have had several battery issues that I just believed to be bad luck and would get a new battery under warranty but it has gotten worse lately. It led me to look online and I notice I am not nearly the only one as this complaint has been brought up my numerous people. It is in regards to my 2015 Subaru legacy and how I’m not certain if my car will start if I make a few short trips where I’m “in and out” of the car more than 3 times in a short period of time. There is definitely a parasitic draw issue from the vehicle and it is a safety concern in not knowing if your vehicle is going to start or if you’ll need a jump or worse be stranded. With the amount of complaints on this issue I would have thought there would be a recall. I know there are safety bulletins but nothing that the dealer or Subaru themselves will address. I have also signed up for the battery settlement case but have not heard back in regards to this. I am really wanting to know if there is a solution because I’ve read a lot of reviews where this is happening in newer models also. It needs to be addressed and a resolution should be offered because it is happening to A LOT of Subarus. My other concern was the seats and moonroof. The leather driver seat has torn up and I have put covers over it to look similar but I use a sun screen for the vehicle often and it still tore up the seat. Lastly the moonroof has a defect that the dealer wouldn’t address. There is something wrong with the seal and loud wind gets in somewhere and makes the vehicle shake as though you turned up a base speakers to the loudest setting. The battery issue has been going on for years as well as the moonroof that has a spot that is allowing in air and causes the vehicle to shake. Please help hold subaru accountable for these issues and get back to me with some sort of solution! Thank you for your time.

NHTSA ODI #11582009

Official recalls

3

16V251000 · Electronic Stability Control (esc)

Apr 27, 2016

Subaru of America, Inc. (Subaru) is recalling certain model year 2015 Legacy and Outback vehicles manufactured on July 20, 2015. The brake fluid used in these vehicles may contain excess moisture which may adversely affect the performance of the electronic stability control system. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 126, "Electronic Stability Control Systems."

Consequence & remedy

Consequence: Poor performance of the electronic stability control system when it is activated may result in a loss of vehicle control, increasing the risk of a crash.

Remedy: Subaru will notify owners, and dealers will perform an ABS activation, then flush and replace the brake fluid, free of charge. The recall began on May 20, 2016. Owners may contact Subaru customer service at 1-800-782-2783. Subaru's number for this recall is WTC-64.

15V502000 · Power Train:automatic Transmission; Power Train:driveline:driveshaft

Aug 10, 2015

Subaru of America, Inc. (Subaru) is recalling certain 2015 and 2016 model year Subaru Legacy 4-Door and Outback vehicles manufactured July 3, 2015, to July 27, 2015. Transmission oil may leak from a deformed seal cap on the propeller shaft yoke.

Consequence & remedy

Consequence: If the transmission oil leaks onto the exhaust pipe, there is a possible risk of fire.

Remedy: Subaru will notify owners, and dealers will replace the propeller shaft, free of charge. The recall began on August 28, 2015. Owners may contact 1-800-782-2783. Subaru's number for this recall is WQU-56.

Additional source detail variants (2)

Power Train:driveline:driveshaft

Subaru of America, Inc. (Subaru) is recalling certain 2015 and 2016 model year Subaru Legacy 4-Door and Outback vehicles manufactured July 3, 2015, to July 27, 2015. Transmission oil may leak from a deformed seal cap on the propeller shaft yoke.

Consequence: If the transmission oil leaks onto the exhaust pipe, there is a possible risk of fire.

Remedy: Subaru will notify owners, and dealers will replace the propeller shaft, free of charge. The recall began on August 28, 2015. Owners may contact 1-800-782-2783. Subaru's number for this recall is WQU-56.

Power Train:automatic Transmission

Subaru of America, Inc. (Subaru) is recalling certain 2015 and 2016 model year Subaru Legacy 4-Door and Outback vehicles manufactured July 3, 2015, to July 27, 2015. Transmission oil may leak from a deformed seal cap on the propeller shaft yoke.

Consequence: If the transmission oil leaks onto the exhaust pipe, there is a possible risk of fire.

Remedy: Subaru will notify owners, and dealers will replace the propeller shaft, free of charge. The recall began on August 28, 2015. Owners may contact 1-800-782-2783. Subaru's number for this recall is WQU-56.

15V366000 · Exterior Lighting:brake Lights:switch; Forward Collision Avoidance: Crash Imminent Braking

Jun 12, 2015

Subaru of America, Inc. (Subaru) is recalling certain model year 2015 Legacy vehicles manufactured March 10, 2014, to April 16, 2015, Outback vehicles manufactured February 24, 2014, to April 16, 2015, Impreza vehicles manufactured September 9, 2014, to April 14, 2015, XV Crosstrek vehicles manufactured October 16, 2014, to April 15, 2015, and 2016 WRX vehicles manufactured March 23, 2015, and equipped with the Eyesight Driver Assist System. If the switch that activates the brake lights fails, the automatic pre-collision braking component of the driver assist system will not function.

Consequence & remedy

Consequence: If the automatic pre-collision braking system does not function as intended, the vehicle will not react to an obstacle in its path, increasing the risk of a crash.

Remedy: Subaru will notify owners, and dealers will reprogram the driver assist system, free of charge. The recall began on July 20, 2015. Owners may contact Subaru customer service at 1-800-782-2783. Subaru's number for this recall is WQS-54.

Additional source detail variants (2)

Forward Collision Avoidance: Crash Imminent Braking

Subaru of America, Inc. (Subaru) is recalling certain model year 2015 Legacy vehicles manufactured March 10, 2014, to April 16, 2015, Outback vehicles manufactured February 24, 2014, to April 16, 2015, Impreza vehicles manufactured September 9, 2014, to April 14, 2015, XV Crosstrek vehicles manufactured October 16, 2014, to April 15, 2015, and 2016 WRX vehicles manufactured March 23, 2015, and equipped with the Eyesight Driver Assist System. If the switch that activates the brake lights fails, the automatic pre-collision braking component of the driver assist system will not function.

Consequence: If the automatic pre-collision braking system does not function as intended, the vehicle will not react to an obstacle in its path, increasing the risk of a crash.

Remedy: Subaru will notify owners, and dealers will reprogram the driver assist system, free of charge. The recall began on July 20, 2015. Owners may contact Subaru customer service at 1-800-782-2783. Subaru's number for this recall is WQS-54.

Exterior Lighting:brake Lights:switch

Subaru of America, Inc. (Subaru) is recalling certain model year 2015 Legacy vehicles manufactured March 10, 2014, to April 16, 2015, Outback vehicles manufactured February 24, 2014, to April 16, 2015, Impreza vehicles manufactured September 9, 2014, to April 14, 2015, XV Crosstrek vehicles manufactured October 16, 2014, to April 15, 2015, and 2016 WRX vehicles manufactured March 23, 2015, and equipped with the Eyesight Driver Assist System. If the switch that activates the brake lights fails, the automatic pre-collision braking component of the driver assist system will not function.

Consequence: If the automatic pre-collision braking system does not function as intended, the vehicle will not react to an obstacle in its path, increasing the risk of a crash.

Remedy: Subaru will notify owners, and dealers will reprogram the driver assist system, free of charge. The recall began on July 20, 2015. Owners may contact Subaru customer service at 1-800-782-2783. Subaru's number for this recall is WQS-54.

Model-level recall history does not show whether a particular VIN is affected or has received a repair. Check a VIN with NHTSA ↗

NHTSA investigations

1

EA21002 · Desiccated Air Bag Inflator Rupture

Opened Sep 17, 2021 · No close date supplied

Status: open (inferred from source dates) · Air Bags:frontal:driver Side:inflator Module; Air Bags:frontal:passenger Side:inflator Module

From 2000 through 2017, Takata produced millions of air bag inflators using two types of phase-stabilized ammonium nitrate ("PSAN") propellant -- propellant 2004 and propellant 2004L. After prolonged exposure to high temperature cycles and humidity, inflators using propellant 2004 can degrade, causing the propellant to burn too quickly when ignited. The rapid burning can cause the inflator to rupture during deployment, potentially causing serious or even fatal injury to vehicle occupants. See 2016 Blomquist Report at www.nhtsa.gov/sites/nhtsa.gov/files/documents/expert_report-hrblomquist.pdf.Consequently, all frontal inflators using propellant 2004 that do not contain a "desiccant" (a substance that traps and holds moisture) in US vehicles are under recall. These "non-desiccated" inflators either have been or are required to be replaced.In some cases, the remedy part for these recalled inflators was, or will be, an inflator using either propellant 2004 or 2004L that does contain a desiccant. None of these "desiccated" remedy parts (which were installed in older model year vehicles) are currently under recall for a degradation concern. Certain subsets of desiccated PSAN inflators using propellant 2004 for use as original equipment, however, have been recalled for a degradation concern. All Takata inflators produced with propellant 2004L contain desiccant, and none of these desiccated inflators using propellant 2004L are under recall for a degradation concern. There have been no reported field ruptures in any non-recalled desiccated PSAN inflators.It is understood that desiccants fully saturate at some threshold, at which point any additional moisture will not be captured. This means the degradation process observed in non-desiccated inflators using propellant 2004 may also occur in non-recalled desiccated inflators using propellant 2004, assuming additional moisture enters the inflator and high temperature cycling occurs. Based on available information, desiccant saturation can occur within the first five years in the worst environments, and the time required for full saturation is affected by multiple factors. While no present safety risk has been identified, further work is needed to evaluate the future risk of non-recalled desiccated inflators using propellant 2004.Three entities -- Takata (now known as TK Global), the Independent Testing Coalition, and Exponent -- have been studying the long-term behavior of Takata desiccated PSAN inflators using propellant 2004L (as well as 2004) in the presence of moisture and temperature cycling. The research efforts, which include development of predictive modeling techniques and field sample analysis, are ongoing. To date, none of the researchers have identified field evidence showing that propellant 2004L is undergoing a degradation process that leads to aggressive deployment and potential rupture. However, the time in service of such inflators remains short compared to that of the inflators using propellant 2004. Further study is needed to assess the long-term safety of desiccated inflators using propellant 2004L.The Office of Defects Investigation is opening this investigation to examine whether a safety defect related to propellant degradation exists in non-recalled desiccated PSAN frontal inflators manufactured by Takata. This investigation will require extensive information on Takata production processes and surveys of inflators in the field. Lists of recall actions that may have used desiccated PSAN inflators as remedy parts, as well as the makes and models originally manufactured with them, is available with the downloadable version of this document (see nhtsa.gov/recalls?nhtsaId=EA21002 -- note this information is subject to change/revision as the investigation proceeds). This investigation does not supersede EA15-001, which remains open.

Additional source detail variants (2)

Air Bags:frontal:driver Side:inflator Module

From 2000 through 2017, Takata produced millions of air bag inflators using two types of phase-stabilized ammonium nitrate ("PSAN") propellant -- propellant 2004 and propellant 2004L. After prolonged exposure to high temperature cycles and humidity, inflators using propellant 2004 can degrade, causing the propellant to burn too quickly when ignited. The rapid burning can cause the inflator to rupture during deployment, potentially causing serious or even fatal injury to vehicle occupants. See 2016 Blomquist Report at www.nhtsa.gov/sites/nhtsa.gov/files/documents/expert_report-hrblomquist.pdf.Consequently, all frontal inflators using propellant 2004 that do not contain a "desiccant" (a substance that traps and holds moisture) in US vehicles are under recall. These "non-desiccated" inflators either have been or are required to be replaced.In some cases, the remedy part for these recalled inflators was, or will be, an inflator using either propellant 2004 or 2004L that does contain a desiccant. None of these "desiccated" remedy parts (which were installed in older model year vehicles) are currently under recall for a degradation concern. Certain subsets of desiccated PSAN inflators using propellant 2004 for use as original equipment, however, have been recalled for a degradation concern. All Takata inflators produced with propellant 2004L contain desiccant, and none of these desiccated inflators using propellant 2004L are under recall for a degradation concern. There have been no reported field ruptures in any non-recalled desiccated PSAN inflators.It is understood that desiccants fully saturate at some threshold, at which point any additional moisture will not be captured. This means the degradation process observed in non-desiccated inflators using propellant 2004 may also occur in non-recalled desiccated inflators using propellant 2004, assuming additional moisture enters the inflator and high temperature cycling occurs. Based on available information, desiccant saturation can occur within the first five years in the worst environments, and the time required for full saturation is affected by multiple factors. While no present safety risk has been identified, further work is needed to evaluate the future risk of non-recalled desiccated inflators using propellant 2004.Three entities -- Takata (now known as TK Global), the Independent Testing Coalition, and Exponent -- have been studying the long-term behavior of Takata desiccated PSAN inflators using propellant 2004L (as well as 2004) in the presence of moisture and temperature cycling. The research efforts, which include development of predictive modeling techniques and field sample analysis, are ongoing. To date, none of the researchers have identified field evidence showing that propellant 2004L is undergoing a degradation process that leads to aggressive deployment and potential rupture. However, the time in service of such inflators remains short compared to that of the inflators using propellant 2004. Further study is needed to assess the long-term safety of desiccated inflators using propellant 2004L.The Office of Defects Investigation is opening this investigation to examine whether a safety defect related to propellant degradation exists in non-recalled desiccated PSAN frontal inflators manufactured by Takata. This investigation will require extensive information on Takata production processes and surveys of inflators in the field. Lists of recall actions that may have used desiccated PSAN inflators as remedy parts, as well as the makes and models originally manufactured with them, is available with the downloadable version of this document (see nhtsa.gov/recalls?nhtsaId=EA21002 -- note this information is subject to change/revision as the investigation proceeds). This investigation does not supersede EA15-001, which remains open.

Air Bags:frontal:passenger Side:inflator Module

From 2000 through 2017, Takata produced millions of air bag inflators using two types of phase-stabilized ammonium nitrate ("PSAN") propellant -- propellant 2004 and propellant 2004L. After prolonged exposure to high temperature cycles and humidity, inflators using propellant 2004 can degrade, causing the propellant to burn too quickly when ignited. The rapid burning can cause the inflator to rupture during deployment, potentially causing serious or even fatal injury to vehicle occupants. See 2016 Blomquist Report at www.nhtsa.gov/sites/nhtsa.gov/files/documents/expert_report-hrblomquist.pdf.Consequently, all frontal inflators using propellant 2004 that do not contain a "desiccant" (a substance that traps and holds moisture) in US vehicles are under recall. These "non-desiccated" inflators either have been or are required to be replaced.In some cases, the remedy part for these recalled inflators was, or will be, an inflator using either propellant 2004 or 2004L that does contain a desiccant. None of these "desiccated" remedy parts (which were installed in older model year vehicles) are currently under recall for a degradation concern. Certain subsets of desiccated PSAN inflators using propellant 2004 for use as original equipment, however, have been recalled for a degradation concern. All Takata inflators produced with propellant 2004L contain desiccant, and none of these desiccated inflators using propellant 2004L are under recall for a degradation concern. There have been no reported field ruptures in any non-recalled desiccated PSAN inflators.It is understood that desiccants fully saturate at some threshold, at which point any additional moisture will not be captured. This means the degradation process observed in non-desiccated inflators using propellant 2004 may also occur in non-recalled desiccated inflators using propellant 2004, assuming additional moisture enters the inflator and high temperature cycling occurs. Based on available information, desiccant saturation can occur within the first five years in the worst environments, and the time required for full saturation is affected by multiple factors. While no present safety risk has been identified, further work is needed to evaluate the future risk of non-recalled desiccated inflators using propellant 2004.Three entities -- Takata (now known as TK Global), the Independent Testing Coalition, and Exponent -- have been studying the long-term behavior of Takata desiccated PSAN inflators using propellant 2004L (as well as 2004) in the presence of moisture and temperature cycling. The research efforts, which include development of predictive modeling techniques and field sample analysis, are ongoing. To date, none of the researchers have identified field evidence showing that propellant 2004L is undergoing a degradation process that leads to aggressive deployment and potential rupture. However, the time in service of such inflators remains short compared to that of the inflators using propellant 2004. Further study is needed to assess the long-term safety of desiccated inflators using propellant 2004L.The Office of Defects Investigation is opening this investigation to examine whether a safety defect related to propellant degradation exists in non-recalled desiccated PSAN frontal inflators manufactured by Takata. This investigation will require extensive information on Takata production processes and surveys of inflators in the field. Lists of recall actions that may have used desiccated PSAN inflators as remedy parts, as well as the makes and models originally manufactured with them, is available with the downloadable version of this document (see nhtsa.gov/recalls?nhtsaId=EA21002 -- note this information is subject to change/revision as the investigation proceeds). This investigation does not supersede EA15-001, which remains open.