IllustrationFUEL FILLER DOOR FREEZES SHUT. GAS TANK CANNOT BE REFILLED UNTILL ICE AT THE BOTTOM OF THE DOOR IS MELTED. THIS HAPPENS BOTH WHILE MOVING AND/OR STATIONARY.
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 →How this year compares
Owner complaints by model year
Compare all Legacy years →Counts vary with age, sales and reporting. They are not failure rates.
What owners reported most
All reported categories
Tap a category to read its complaints. One report may name several components.
When problems were reported
Mileage at the reported incident
620–25K
1725–50K
850–75K
975–100K
5100–150K
3150K+
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 reportsGAS CAP LID DOES NOT OPEN. WE TOOK THE AUTO INTO DEALERSHIP JUNE 30, 2015 AND GAVE THEM TSB-09-60-15. MILEAGE 5987. TEMPS IN THE 70'S. THEY GREASED THE GAS LID CONTACT. I INDICATED THE TSB INDICATED SOMETHING OTHER THAN THAT. THEY TOOK BACK INTO SHOP AND GROUND DOWN THE LID RELEASE CONTACT. DROVE HOME. TRIED TO OPEN GAS …
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GAS CAP LID DOES NOT OPEN. WE TOOK THE AUTO INTO DEALERSHIP JUNE 30, 2015 AND GAVE THEM TSB-09-60-15. MILEAGE 5987. TEMPS IN THE 70'S. THEY GREASED THE GAS LID CONTACT. I INDICATED THE TSB INDICATED SOMETHING OTHER THAN THAT. THEY TOOK BACK INTO SHOP AND GROUND DOWN THE LID RELEASE CONTACT. DROVE HOME. TRIED TO OPEN GAS CAP LID AND IT WOULD NOT OPEN. WE ARE CONCERNED ABOUT DRIVING AUTO ANY DISTANCE BY ONESELF BECAUSE IT NOW TAKES TWO PEOPLE TO PUT GAS INTO AUTO. ONE TO PULL UP LEVER AND ONE TO PRY OPEN THE LID ON THE OUTSIDE. I AM SEEING NUMEROUS PROBLEMS WITH SEVERAL OTHER SUBARU MODELS BESIDES THE LEGACY. SUCH A SIMPLE MANUFACTURING FLAW SHOULD BE ABLE TO BE FIXED. LOVE THE AUTO BUT THIS IS REALLY REALLY AN ANNOYING SIMPLE FLAW. ONE PERSON'S COMMENT ON A TSB PERTAINING TO THIS ISSUE SAID IF THE LUBE AND GRINDING DOES NOT FIX THE ISSUE, THE ENTIRE CAP ASSEMBLY NEEDS TO BE REPLACED. I HAVE NOT DISCUSSED THIS WITH THE DEALER YET. THIS ISSUE HAPPENS IN ALL TEMPS. CURRENTLY 60 IN GARAGE AND CAP DOES NOT OPEN. MILEAGE 10365.
TL* THE CONTACT OWNED A 2015 SUBARU LEGACY. WHILE DRIVING AT AN UNSPECIFIED RATE OF SPEED, AN ANIMAL WENT ACROSS THE DRIVER'S PATH. THE DRIVER VEERED TO THE RIGHT AND CRASHED INTO A TREE. THE VEHICLE ERUPTED INTO FLAMES. WEEKS PRIOR TO THE CRASH, THE VEHICLE WAS TAKEN TO THE DEALER DUE TO VARIOUS WARNING LIGHTS RANDOMLY FLASHING…
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TL* THE CONTACT OWNED A 2015 SUBARU LEGACY. WHILE DRIVING AT AN UNSPECIFIED RATE OF SPEED, AN ANIMAL WENT ACROSS THE DRIVER'S PATH. THE DRIVER VEERED TO THE RIGHT AND CRASHED INTO A TREE. THE VEHICLE ERUPTED INTO FLAMES. WEEKS PRIOR TO THE CRASH, THE VEHICLE WAS TAKEN TO THE DEALER DUE TO VARIOUS WARNING LIGHTS RANDOMLY FLASHING ON THE INSTRUMENT PANEL. THE DEALER REPAIRED THE VEHICLE ACCORDING TO A MANUFACTURER'S RECALL; HOWEVER, THE REMEDY MAY HAVE BEEN INSUFFICIENT AND CAUSED THE FAILURE. A POLICE REPORT WAS FILED. THE DRIVER SIDE AIR BAG DEPLOYED WITH FORCE. THE DRIVER SUSTAINED EXTENSIVE ABRASIONS TO THE HEAD, A FRACTURED RIGHT FEMUR, FOUR LATERAL FRACTURES IN THE ARMS, FRACTURES TO THE LEFT ELBOW WITH METAL PLATES, AND BURNS TO THE BACK. MEDICAL ATTENTION WAS REQUIRED. THE VEHICLE WAS TOWED. THE VIN WAS NOT INCLUDED IN NHTSA CAMPAIGN NUMBERS: 15V502000 (POWER TRAIN) AND 15V366000 (EXTERIOR LIGHTING, FORWARD COLLISION AVOIDANCE). THE APPROXIMATE FAILURE MILEAGE WAS 25,100.
TL* THE CONTACT OWNS A 2015 SUBARU LEGACY. THE CONTACT STATED THAT THE VEHICLE WAS PURCHASED AND UNABLE TO BE DRIVEN FOR SEVERAL MONTHS DUE TO A FAILURE WITH THE FORWARD COLLISION AVOIDANCE FEATURE NOT FUNCTIONING PROPERLY. THE CONTACT NOTIFIED THE FIRST DEALER AND THEY WERE NOT ABLE TO REPLICATE AND DIAGNOSE THE FAILURE. THE CO…
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TL* THE CONTACT OWNS A 2015 SUBARU LEGACY. THE CONTACT STATED THAT THE VEHICLE WAS PURCHASED AND UNABLE TO BE DRIVEN FOR SEVERAL MONTHS DUE TO A FAILURE WITH THE FORWARD COLLISION AVOIDANCE FEATURE NOT FUNCTIONING PROPERLY. THE CONTACT NOTIFIED THE FIRST DEALER AND THEY WERE NOT ABLE TO REPLICATE AND DIAGNOSE THE FAILURE. THE CONTACT LATER TESTED THE VEHICLE NUMEROUS TIMES AND NOTICED THAT THE FAILURE WAS PROGRESSING. THE VEHICLE WAS TAKEN BACK TO THE FIRST DEALER A SECOND TIME UPON RECEIVING NHTSA CAMPAIGN NUMBER: 15V366000 (EXTERIOR LIGHTING, FORWARD COLLISION AVOIDANCE) AND THEY INDICATED THAT THE VEHICLE DID NOT NEED TO BE SERVICED UNDER THE RECALL. THE VEHICLE WAS TAKEN TO A SECOND DEALER TO RECEIVE THE RECALL REMEDY AND THE CONTACT STATED THAT THE DEALER HAD THE VEHICLE FOR LONGER THAN TWO MONTHS FOR THE REPAIRS. THE CONTACT WAS UNCERTAIN IF THE MANUFACTURERS REMEDY PROVIDED A PERMANENT SOLUTION AND WAS CONCERNED THAT THE FAILURE WOULD REOCCUR. THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 1,500. *TR
WENT OUTSIDE TO WASH THE CAR AND BEFORE I EVEN GOT STARTED I NOTICED A CRACK IN THE WINDSHIELD. I LOOKS LIKE IT STARTED IN THE VERY CENTER AT THE BOTTOM AND TRAVELED UP AND THEN TO THE PASSENGER'S SIDE. THE CRACK IS ABOUT 12 INCHES LONG. NO IMPACT, VEHICLE WASN'T EVEN MOVING. THERE WAS NO CRACK THE DAY BEFORE.
TL* THE CONTACT OWNS A 2015 SUBARU LEGACY. WHILE DRIVING AT AN UNKNOWN SPEED, THE ACCELERATOR PEDAL'S COVER DETACHED FROM THE PEDAL. THE VEHICLE WOULD NOT STOP EVEN WHEN THE BRAKE PEDAL WAS DEPRESSED DUE TO THE COVER ENCASING THE PEDAL. THE VEHICLE WAS TAKEN TO THE DEALER WHERE IT WAS CONFIRMED THAT THE PEDAL COVER DETACHED. THE…
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TL* THE CONTACT OWNS A 2015 SUBARU LEGACY. WHILE DRIVING AT AN UNKNOWN SPEED, THE ACCELERATOR PEDAL'S COVER DETACHED FROM THE PEDAL. THE VEHICLE WOULD NOT STOP EVEN WHEN THE BRAKE PEDAL WAS DEPRESSED DUE TO THE COVER ENCASING THE PEDAL. THE VEHICLE WAS TAKEN TO THE DEALER WHERE IT WAS CONFIRMED THAT THE PEDAL COVER DETACHED. THERE WAS NO REMEDY FOR THE ISSUE. THE PEDAL COVER WAS NEVER RE-ATTACHED. THE MANUFACTURER WAS NOT MADE AWARE OF THE ISSUE. THE VIN WAS INVALID. THE FAILURE MILEAGE WAS APPROXIMATELY 7,200.
WHILE TRAVELING ON THE OPEN INTERSTATE, THE WINDSHIELD STARTED TO CRACK. THE CRACK STARTED IN THE LOWER DRIVER SIDE CORNER, UNDER THE WIPER BLADE. IN LESS THAN 30 MIN, THE CRACK EXTENDED UP AND OVER, IN-FRONT OF THE DRIVER'S VIEW AND EXTENDED TO THE CENTER. FROM THE OUTSIDE, YOU CAN FEEL THE CRACK. IF YOU PUSH ON THE WINDSHI…
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WHILE TRAVELING ON THE OPEN INTERSTATE, THE WINDSHIELD STARTED TO CRACK. THE CRACK STARTED IN THE LOWER DRIVER SIDE CORNER, UNDER THE WIPER BLADE. IN LESS THAN 30 MIN, THE CRACK EXTENDED UP AND OVER, IN-FRONT OF THE DRIVER'S VIEW AND EXTENDED TO THE CENTER. FROM THE OUTSIDE, YOU CAN FEEL THE CRACK. IF YOU PUSH ON THE WINDSHIELD, YOU CAN TELL THAT THE WINDSHIELD IS WEAK, POOR QUALITY, AND A OBVIOUS SAFETY ISSUE.
TAKATARECALL, ONDEC16,2015 DRIVING ON RT81&LITTLECITYRD,AT SIGNAL LIGHT.I HAD GREEN LIGHT AND WAS HIT FROM RIGHT SIDE BY ANYOTHER CAR WHICH RAN RED LIGHTHIT MY FRONT END OF CARSPUN ME AROUNDAND NOT ONE AIR BAG WENT OFF,DAMAGE WAS ALMOST11,000WHAT IS WRONG WITH SUBARUAIRBAGS
WE HAVE OWNED THE CAR FOR 14 MONTH'S AND HAVE HAD TO REPLACE THE WINDSHIELD 6 TIMES DUE TO CRACKING. OTHER CARS IN THE SAME HOUSEHOLD HAVE NEVER HAD TO HAVE THEIR WINDSHIELDS REPLACED. THERE IS OBVIOUSLY SOME KIND OF DEFECT ASSOCIATED WITH THIS VEHICLE. CONTACTED SUBARU DEALER WITH NO HELP.
WINDSHIELD CRACKS FROM EDGES. NO NOTICEABLE CHIPS. CRACK STARTED WITH ROCK HITS. POSSIBLE DEFECTIVE GLASS.
Official recalls
316V251000 · 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
1EA21002 · 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.