NHTSA owner reports · September 18, 2026 snapshot.
Fuel/propulsion System complaints
18 reportsClear category filterMileage unknown · Jun 26, 2026
EngineFuel/propulsion System
NHTSA issued a notice for a recall on the 2015 Subaru Outback for an exhaust pipe bellows crack which causes exhaust noise and odor which affects emission and engine performance. I had noticed our Subaru's exhaust smoke coming in through the air vents while idling and also a general loss of power for the vehicle. When I dug in…
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NHTSA issued a notice for a recall on the 2015 Subaru Outback for an exhaust pipe bellows crack which causes exhaust noise and odor which affects emission and engine performance. I had noticed our Subaru's exhaust smoke coming in through the air vents while idling and also a general loss of power for the vehicle. When I dug into the causes, I came across this recall and did the VIN look up on the NHTSA website and also the Subaru website for active recalls. The Subaru website states that the recall was completed. I then called the subaru retailer to check if there were any records for the recall work that was completed for NHTSA ID Number: 10199936. They could not find any records. I called in Subaru corporate to see if they could shed any light on the recall. Subaru corporate says that the recall work was performed on August 6th, 2020 but is unable to tell me where it was performed or even if it was actually replaced. My local Subaru dealer has no records and Subaru corporate says that the work was performed. I am stuck with an exhaust leak that is potentially dangerous as time goes on where it might fail emissions. Subaru corporate has not wanted to address this or investigate the discrepancy, but instead asks me to work with the dealer to get records. The dealer says there's no records of the work ever being done. So I'm in limbo with a particularly faulty car.
NHTSA ODI #11746783
Mileage unknown · May 12, 2025
Fuel/propulsion System
Within the last few months, my 2015 Outback has been unreliable with the fuel gauge indicator, causing me to run out of gas three times, stranded roadside, with supposedly 30 miles in rank. Fortunately, there were no accidents, but two out of three times, I was left stranded on highways, that put me at risk of being struck.
NHTSA ODI #11660515
Mileage unknown · Feb 2, 2024
Fuel/propulsion System
Our 2015 Subaru Outback occasionally accelerates sharply without the driver's foot being on the gas peddle. It always happens when decelerating and applying the brakes. Suddenly, the engine roars and revs up, all while the driver is depressing the brake pedal, desperately trying to bring the vehicle to a safe stop. In our case, …
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Our 2015 Subaru Outback occasionally accelerates sharply without the driver's foot being on the gas peddle. It always happens when decelerating and applying the brakes. Suddenly, the engine roars and revs up, all while the driver is depressing the brake pedal, desperately trying to bring the vehicle to a safe stop. In our case, we've always been able to stop without hitting anything, but we've had some near misses. It seems to happen in the winter. The Subaru dealer we purchased the vehicle from denies any knowledge of this particular problem, even though numerous drivers have reported similar incidents.
NHTSA ODI #11569433
Mileage unknown · Sep 10, 2022
Air BagsEngineFuel/propulsion SystemCrash
Entering a residential garage to park; experienced sudden acceleration while braking. Vehicle went through drywall/wall about 2 feet. Placed vehicle in park to stop vehicle. No airbags went off. Driving vehicle to repair shop later; experienced same rapid unexpected acceleration with different driver. No issue with floor mats…
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Entering a residential garage to park; experienced sudden acceleration while braking. Vehicle went through drywall/wall about 2 feet. Placed vehicle in park to stop vehicle. No airbags went off. Driving vehicle to repair shop later; experienced same rapid unexpected acceleration with different driver. No issue with floor mats. OEM mats. Service center cannot provide any insight or reproduction of event.
NHTSA ODI #11483793
Mileage unknown · Sep 23, 2021
EngineFuel/propulsion System
While driving at highway speed and traveling over about 6 hours, the car simply shut off. We were traveling on the highway in the passing lane. Without warning the car began to slow down rapidly, no dash lights on, but the engine was off. We managed to cross two lanes of traffic without power assist and once on the shoulder and …
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While driving at highway speed and traveling over about 6 hours, the car simply shut off. We were traveling on the highway in the passing lane. Without warning the car began to slow down rapidly, no dash lights on, but the engine was off. We managed to cross two lanes of traffic without power assist and once on the shoulder and slowing down, the engine lights all came on. Once fully stopped, we turned the car off, waited a few seconds and restarted. We were then able to complete our trip without difficulty. This has happened twice. The dealer has done full diagnostics twice but has been unable to find the problem. We have heard that other year Subaru outbacks have been recalled for this problem but our year isn't included.
NHTSA ODI #11434112
Mileage unknown · Jul 28, 2021
Fuel/propulsion System
We called Subaru Roadside Assistance Sunday, July 25, 2021 because the Subaru lost power, as though it were out of gas, but the gage showed we had over an eighth of a tank. We mentioned this to the roadside assistant Rep. several times. She took our cell and credit card #s and said she ordered us a tow truck. I asked if the driv…
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We called Subaru Roadside Assistance Sunday, July 25, 2021 because the Subaru lost power, as though it were out of gas, but the gage showed we had over an eighth of a tank. We mentioned this to the roadside assistant Rep. several times. She took our cell and credit card #s and said she ordered us a tow truck. I asked if the driver will have a gas can with. She said, "Well do you need a tow or fuel". Again we repeated we didn't know and explained again what happened. She said it would be 60-90 minutes. It was 94 degrees, we had no water, no shade, it was horrible. After 90 minutes still nobody came. We called again to see how much longer it would be. COME TO FIND OUT, THEY DIDN'T SEND ANYONE!!!. They said they didn't know if we needed a toe or fuel, so they didn't send anyone, didn't call, NOTHING. They said it would be another 90 minutes. We told them to forget it, hung up and went to a nearby house and the guy gave us a bottle of water and from a gas can, provided us enough gas to get to the next gas station 11 miles away. I tried calling subaru headquarters to report the issue and to let them know if our credit card was charged, they need to reimburse it since we did not receive service, but I was on hold for so long, I hung up and emailed them - 3 times and I NEVER heard anything back from them. So here I am reporting to not rely on their gas gage and reporting a safety concern that they would leave people in massive heat, probably would in the terrible cold as well. They do not call to let you know that nobody is coming. Subaru roadside assistance is one big joke. Subaru service is a big joke because obviously they don't care since they never responded to any of my emails. Needless to say, we will never call their roadside assistance again and will NEVER buy a subaru again since they have shown lack of interest. Thank you.
NHTSA ODI #11426813
2 miles · Aug 11, 2020
EngineFuel/propulsion SystemPower Train
I WAS GOING 55 MPH ON A STRAIGHT FLAT SURFACE WHEN ALL OF A SUDDEN THE RPM'S SHOT UP TO AROUND 4000 BUT THE CAR WAS NOT ACCELERATING. IT WAS LIKE IT WENT INTO NEUTRAL. I PULLED OVER TO THE SIDE OF THE ROAD AND THE CAR PROCEEDED TO DIE. FORTUNATELY, IT STARTED RIGHT UP AND I DROVE HOME. I HAD A ALMOST A FULL TANK OF GAS. I HAD…
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I WAS GOING 55 MPH ON A STRAIGHT FLAT SURFACE WHEN ALL OF A SUDDEN THE RPM'S SHOT UP TO AROUND 4000 BUT THE CAR WAS NOT ACCELERATING. IT WAS LIKE IT WENT INTO NEUTRAL. I PULLED OVER TO THE SIDE OF THE ROAD AND THE CAR PROCEEDED TO DIE. FORTUNATELY, IT STARTED RIGHT UP AND I DROVE HOME. I HAD A ALMOST A FULL TANK OF GAS. I HAD ONLY DRIVEN IT FOR 5 MINUTES AS I WAS ON MY WAY HOME FROM WORK. I JUST HAD THE OIL/FILTER CHANGED NOT EVEN 2 MONTHS AGO. I HAVE 54,000 DEALER SERVICED MILES ON THE CAR. IT WAS 86 DEGREES OUT. 2015 SUBARU OUTBACK PREMIUM 2.5
NHTSA ODI #11348698
63,000 miles · Oct 8, 2019
Electrical SystemFuel/propulsion System
A SUPPOSED GAS CAP SEAL CAUSED 20 ICONS TO FLASH CONSTANTLY UPON MY DASH. THE CAR HAD BEEN SITTING IN A PARKING GARAGE FOR TWO DAYS PRIOR TO THE INCIDENT
NHTSA ODI #11266946
65,000 miles · Feb 4, 2019
EngineFuel/propulsion SystemUnknown Or Other
PLEASE READ UPLOAD DOCUMENTS. MY 2015 SUBARU OUTBACK BEGAN SHOWING SIGNS OF EXCESSIVE OIL CONSUMPTION IN THE SUMMER 2018. APPARENTLY THIS WAS A KNOWN PROBLEM WITH SUBARU AND CLASS ACTION LAWSUIT WAS FILED AGAINST SUBARU FOR MODELS MADE PRIOR TO 2015. MY VEHICLE FAILED A OIL CONSUMPTION TEST IN THE FALL OF 2018. I WAS TOLD BY WHI…
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PLEASE READ UPLOAD DOCUMENTS. MY 2015 SUBARU OUTBACK BEGAN SHOWING SIGNS OF EXCESSIVE OIL CONSUMPTION IN THE SUMMER 2018. APPARENTLY THIS WAS A KNOWN PROBLEM WITH SUBARU AND CLASS ACTION LAWSUIT WAS FILED AGAINST SUBARU FOR MODELS MADE PRIOR TO 2015. MY VEHICLE FAILED A OIL CONSUMPTION TEST IN THE FALL OF 2018. I WAS TOLD BY WHITE BEAR SUBARU IF THE VEHICLE FAILED AN OIL CONSUMPTION TEST SUBARU OF AMERICA WOULD PAY TO HAVE A NEW SHORT BLOCK INSTALLED DUE TO THIS ONGOING ENGINE DEFECT. HOWEVER, SUBARU OF AMERICA REFUSED TO PAY THE FULL AMOUNT TO HAVE A NEW SHORT BLOCK INSTALLED AS EVEN THOUGH MY CAR WAS MAKE IN 2014 IT IS TECHNICALLY A 2015 THAT THE CLASS ACTION LAWSUIT ONLY PROTECTED CONSUMERS OF MODELS PRIOR TO 2015. ALSO, IN THE FALL OF 2018 THE INTERIOR OF THIS VEHICLE BEGAN TO HAVE A EXHAUST SMELL AND WAS MAKING ME FEEL SICK. THEY DETERMINED THAT PART OF THE EXHAUST SYSTEM WAS BROKEN BUT TOLD ME NOT TO HAVE IT FIXED BEFORE THE NEW SHORT BLOCK WAS INSTALLED AND THE EXHAUST SYSTEM WOULD JUST BECOME CLOGGED WITH THE OIL THE CAR WAS BURNING. I WENT AHEAD HAD HAD THE REPAIR DONE ANYWAY AS THE EXHAUST AIR WAS TERRIBLE.
NHTSA ODI #11174234
67,000 miles · Sep 25, 2018
Fuel/propulsion System
FUEL GAS DOOR STICKS AND WILL NOT OPEN
NHTSA ODI #11131623
Official recalls
5May 11, 2016
Subaru of America, Inc. (Subaru) is recalling certain model year 2016-2017 Legacy and Outback vehicles manufactured February 29, 2016, to May 6, 2016. The steering column on the affected vehicles may have been improperly machined, and as a result, turning the steering wheel may have no effect on the direction of the wheels.
Consequence & remedy
Consequence: The loss of steering ability would increase the risk of a crash.
Remedy: Subaru will notify owners, and dealers will inspect the lot number on the steering column, replacing the steering column, as necessary, free of charge. The recall began May 13, 2016. Owners may contact Subaru customer service at 1-800-782-2783 or by visiting http://www.wtd65.service-campaign.com. Subaru's number for this recall is WTD-65. Note: Until the vehicles have been inspected, owners are advised not to drive their vehicles.
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.
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.
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.
Sep 19, 2014
Subaru of America, Inc. (Subaru) is recalling certain model year 2015 Outback vehicles manufactured January 22, 2014, to August 18, 2014, and equipped with a Subaru accessory trailer hitch assembly. During installation, the trailer hitch mounting nuts may have been overtightened, potentially resulting in failure of the trailer hitch mounting studs.
Consequence & remedy
Consequence: The mounting nut(s) may not provide sufficient force to remain attached to the studs or the studs themselves might break. If this were to happen while a trailer is being towed, the driver might not be able to operate the vehicle as desired or the trailer may detach from the vehicle. Either situation could increase the risk of a crash.
Remedy: Subaru will notify owners, and dealers will replace all eight mounting nuts for the trailer hitch assembly, and will inspect all eight mounting studs for damage, free of charge. The recall began on October 7, 2014. Owners may contact Subaru customer service at 1-800-782-2783. Subaru's number for this recall is WQN-50.
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.