NHTSA owner reports · September 18, 2026 snapshot.
Engine And Engine Cooling complaints
26 reportsClear category filterMileage unknown · Mar 17, 2025
Electrical SystemEngine And Engine Cooling
The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufactur…
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The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure. VIN tool confirms parts not available.
NHTSA ODI #11648795
137,000 miles · Mar 4, 2025
Electrical SystemEngine And Engine Cooling
The contact owns a 2016 BMW 528I. The contact stated that while attempting to activate the heating system, the heating system failed to activate. There was an abnormal coolant odor entering the vehicle through the vents. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL …
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The contact owns a 2016 BMW 528I. The contact stated that while attempting to activate the heating system, the heating system failed to activate. There was an abnormal coolant odor entering the vehicle through the vents. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the failure; however, the manufacturer was unable to confirm when parts would be available. The failure mileage was 137,000. VIN tool confirms parts not available.
NHTSA ODI #11646327
Mileage unknown · Mar 3, 2025
Electrical SystemEngine And Engine Cooling
The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was not yet available. The local dealer was not contacted. The contact stated that the manufacturer had exceeded a reasonable amount of …
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The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was not yet available. The local dealer was not contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was not made aware of the issue. The contact had not experienced a failure. VIN tool confirms parts not available.
NHTSA ODI #11646014
Mileage unknown · Feb 18, 2025
Electrical SystemEngine And Engine Cooling
The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufactur…
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The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was unavailable. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure. VIN tool confirms parts not available.
NHTSA ODI #11643475
37,000 miles · Feb 6, 2025
Electrical SystemEngine And Engine Cooling
The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was unavailable. The local dealer was contacted, and it was confirmed that the part was not yet available. The contact stated that the m…
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The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was unavailable. The local dealer was contacted, and it was confirmed that the part was not yet available. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact stated while driving at an undisclosed speed, there was smoke was coming from the engine compartment into the cabin of the vehicle through the air vents. The cause of the failure was not yet determined. The vehicle was not repaired. The manufacturer and local dealer were notified of the failure. The failure mileage was 37,000. VIN tool confirms parts not available.
NHTSA ODI #11641063
94,000 miles · Jan 29, 2025
Electrical SystemEngine And Engine Cooling
The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time…
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The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact stated that the "Coolant Low - Please Refill", message was occasionally displayed. The contact stated that after refilling the coolant reservoir and driving for a while, the coolant level would be low again. The vehicle was not diagnosed or repaired. The approximate failure mileage was 94,000. VIN tool confirms parts not available.
NHTSA ODI #11639444
Mileage unknown · Jan 28, 2025
Electrical SystemEngine And Engine Cooling
The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time…
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The contact owns a 2016 BMW 528I. The contact received notification of NHTSA Campaign Number: 24V608000 (ENGINE AND ENGINE COOLING, ELECTRICAL SYSTEM); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the issue. The contact had not experienced a failure. VIN tool confirms parts not available.
NHTSA ODI #11639060
151,198 miles · Jan 7, 2025
Electrical SystemEngine And Engine CoolingSuspension
The contact owns a 2016 BMW 528I. The contact stated that there was an abnormal burning odor coming from the vehicle while at a stop. The contact detected fumes underneath the hood and there was oil on the alternator. The contact stated that the tires were replaced, but the vehicle was not aligned. The contact stated that the dr…
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The contact owns a 2016 BMW 528I. The contact stated that there was an abnormal burning odor coming from the vehicle while at a stop. The contact detected fumes underneath the hood and there was oil on the alternator. The contact stated that the tires were replaced, but the vehicle was not aligned. The contact stated that the driveshaft had dropped and was making an abnormal rubbing sound. The oil light was illuminated. The vehicle was taken to an independent mechanic who determined that the rear differential needed to be replaced. The vehicle was repaired, but the failure recurred. The contact received notification of NHTSA Campaign Number: 24V608000 (Engine and Engine Cooling, Electricals System); however, the part to do the recall repair was not yet available. The local dealer was contacted. The vehicle was taken to the local dealer for a routine oil change and the contact was made aware of an oil leak. The vehicle was diagnosed again, and the contact was informed that the rear differential needed to be replaced. The vehicle was not repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was not made aware of the issue. The failure mileage was approximately 151,198. VIN tool confirms parts not available.
NHTSA ODI #11634664
80,000 miles · Dec 20, 2024
Electrical SystemEngine And Engine Cooling
The contact owns a 2016 BMW 528I. The contact stated while driving 50-60 MPH, there was smoke coming from underneath the hood and out of the exhaust pipes. The coolant temperature warning light and several other unknown warning lights were illuminated. The vehicle sputtered and stalled. The contact was able to pull to the side o…
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The contact owns a 2016 BMW 528I. The contact stated while driving 50-60 MPH, there was smoke coming from underneath the hood and out of the exhaust pipes. The coolant temperature warning light and several other unknown warning lights were illuminated. The vehicle sputtered and stalled. The contact was able to pull to the side of the road. The vehicle failed to restart and was towed to the dealer, where it was diagnosed that the water pump had failed, causing several damages to the vehicle, including engine failure. The vehicle had not been repaired due to the cost. The contact received notification of NHTSA Campaign Number: 24V608000 (Engine and Engine Cooling, Electrical System); however, the part to do the recall repair was not yet available. The local dealer was contacted. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the failure, but no assistance was provided. The failure mileage was approximately 80,000. VIN tool confirms parts not available.
NHTSA ODI #11631745
90,000 miles · Dec 5, 2024
Electrical SystemEngine And Engine Cooling
The contact's wife owns a 2016 BMW 528I. The contact stated that the vehicle was experiencing excessive coolant consumption. The low coolant warning light was illuminated. Additionally, the contact stated while his wife was driving at approximately 35 MPH, the driver noticed that there was steamy smoke coming out from underneath…
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The contact's wife owns a 2016 BMW 528I. The contact stated that the vehicle was experiencing excessive coolant consumption. The low coolant warning light was illuminated. Additionally, the contact stated while his wife was driving at approximately 35 MPH, the driver noticed that there was steamy smoke coming out from underneath the hood. The driver pulled to the side of the road and noticed that fluid was leaking underneath the engine. The vehicle was taken to Sunshine Auto, where the contact's wife was informed that coolant was leaking. The mechanic informed the contact that the turbo needed to be taken out for a diagnostic test. The vehicle was not diagnosed or repaired. The contact received notification of NHTSA Campaign Number: 24V608000 (Engine and Engine Cooling, Electrical System); which the contact related to the failure; however, the part to do the recall repair was not yet available. The local dealer was contacted. The vehicle was not diagnosed or repaired. The contact stated that the manufacturer had exceeded a reasonable amount of time for the recall repair. The manufacturer was made aware of the failure. The failure mileage was approximately 90,000. VIN tool confirms parts not available.
NHTSA ODI #11629030
Official recalls
4Aug 13, 2024
BMW of North America, LLC. (BMW) is recalling certain 2012-2015 X1 sDrive28i, X1 xDrive28i, 2012-2016 Z4 sDrive28i, 528i, 528i xDrive, 328i, 328xi, 2016-2018 X5 xdrive 40e, 2014-2016 228i, 228xi, 428i, 428i xDrive, 328xi Gran Turismo, 2013-2017 X3 sDrive28i, X3 xDrive28i, 2015-2018 X4 xDrive28i, 2015-2016 428xi vehicles. An improperly sealed electrical connector on the water pump may be exposed to water and short circuit.
Consequence & remedy
Consequence: An electrical short increases the risk of a fire.
Remedy: Dealers will inspect and replace the water pump and plug connector as necessary, and install a protective shield, free of charge. Owner notification letters were mailed on March 28, 2025. Owners may contact BMW customer service at 1-800-525-7417.
Additional source detail variants (2)
Electrical System:wiring:connectors/plugs/receptacles
BMW of North America, LLC. (BMW) is recalling certain 2012-2015 X1 sDrive28i, X1 xDrive28i, 2012-2016 Z4 sDrive28i, 528i, 528i xDrive, 328i, 328xi, 2016-2018 X5 xdrive 40e, 2014-2016 228i, 228xi, 428i, 428i xDrive, 328xi Gran Turismo, 2013-2017 X3 sDrive28i, X3 xDrive28i, 2015-2018 X4 xDrive28i, 2015-2016 428xi vehicles. An improperly sealed electrical connector on the water pump may be exposed to water and short circuit.
Consequence: An electrical short increases the risk of a fire.
Remedy: Dealers will inspect and replace the water pump and plug connector as necessary, and install a protective shield, free of charge. Owner notification letters were mailed on March 28, 2025. Owners may contact BMW customer service at 1-800-525-7417.
Engine And Engine Cooling:cooling System:pump
BMW of North America, LLC. (BMW) is recalling certain 2012-2015 X1 sDrive28i, X1 xDrive28i, 2012-2016 Z4 sDrive28i, 528i, 528i xDrive, 328i, 328xi, 2016-2018 X5 xdrive 40e, 2014-2016 228i, 228xi, 428i, 428i xDrive, 328xi Gran Turismo, 2013-2017 X3 sDrive28i, X3 xDrive28i, 2015-2018 X4 xDrive28i, 2015-2016 428xi vehicles. An improperly sealed electrical connector on the water pump may be exposed to water and short circuit.
Consequence: An electrical short increases the risk of a fire.
Remedy: Dealers will inspect and replace the water pump and plug connector as necessary, and install a protective shield, free of charge. Owner notification letters were mailed on March 28, 2025. Owners may contact BMW customer service at 1-800-525-7417.
Dec 20, 2016
BMW of North America, LLC (BMW) is recalling certain model year 2017 BMW 640i, 640i xDrive, 650i, 650i xDrive, M6, 535i, 535i xDrive, 430i, 430i xDrive, 440i, 440i xDrive, M4, X1 sDrive28i, X1 xDrive28i, i3, i8, Rolls-Royce Dawn, Mini Clubman Cooper, Clubman Cooper S, Cooper All4, Cooper S All4, Mini 4-Door Cooper, Cooper S, Mini 2-Door Cooper, Cooper S, John Cooper Works and 2016 BMW 528i, 528i xDrive, 535i, 535i xDrive, 550i, 550i xDrive, M5 and 535d vehicles. The affected vehicles have seat- mounted side air bag inflator initiators that may fail to ignite during a crash.
Consequence & remedy
Consequence: If the air bag inflator initiator fails to ignite, the seat-mounted air bag will not deploy, increasing the risk of injury.
Remedy: BMW will notify owners, and dealers will replace the air bag modules, free of charge. The recall began February 6, 2017. Owners may contact BMW customer service at 1-800-525-7417.
Oct 17, 2016
BMW of North America, LLC (BMW) is recalling certain model year 2016-2017 X1 sDrive28i, X1 xDrive28i, MINI Hardtop 4 Door Cooper, Mini Hardtop 4 Door Cooper S, MINI Cooper Clubman, and Cooper S Clubman, 2017 Rolls-Royce Ghost, and 2016 528i vehicles. The vehicle-sensitive locking mechanism of the seat belt Emergency Locking Retractor (ELR) for the driver's seat may not lock as designed. As such, these vehicles fail to comply with the requirements of the Federal Motor Vehicle Safety Standard (FMVSS) number 209, "Seat Belt Assemblies."
Consequence & remedy
Consequence: In the event of a crash where heavy braking is applied, the Emergency Locking Retractor (ELR) may activate when the occupant is more forward in the seat, possibly increasing the risk of injury.
Remedy: BMW will notify owners, and dealers will replace the driver's seat belt assembly, free of charge. The recall began July 3, 2019. Owners may contact BMW customer service at 1-800-525-7417.
Oct 30, 2015
BMW of North America, LLC (BMW) is recalling certain model year 2016 528i, 528i xDrive, 535i, 535i xDrive, 535d xDrive, M5, 550i, 550i xDrive, and 535d sedans. The affected vehicles have an inboard lower anchor for child restraints on the left rear seat that may have been bent downwards, preventing the child seat from fully engaging both lower anchors. As such, these vehicles may fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 225, "Child Restraint Anchorage Systems."
Consequence & remedy
Consequence: If the child seat is not properly attached to the lower anchors, it can increase the child's risk of injury in the event of a crash.
Remedy: BMW will notify owners, and dealers will inspect and, if necessary, repair the inboard lower anchor on the left rear seat, free of charge. The recall began on December 28, 2015. Owners may contact BMW customer service at 1-800-525-7417.
Additional source detail variants (2)
Child Seat
BMW of North America, LLC (BMW) is recalling certain model year 2016 528i, 528i xDrive, 535i, 535i xDrive, 535d xDrive, M5, 550i, 550i xDrive, and 535d sedans. The affected vehicles have an inboard lower anchor for child restraints on the left rear seat that may have been bent downwards, preventing the child seat from fully engaging both lower anchors. As such, these vehicles may fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 225, "Child Restraint Anchorage Systems."
Consequence: If the child seat is not properly attached to the lower anchors, it can increase the child's risk of injury in the event of a crash.
Remedy: BMW will notify owners, and dealers will inspect and, if necessary, repair the inboard lower anchor on the left rear seat, free of charge. The recall began on December 28, 2015. Owners may contact BMW customer service at 1-800-525-7417.
Seats:mid/rear Assembly
BMW of North America, LLC (BMW) is recalling certain model year 2016 528i, 528i xDrive, 535i, 535i xDrive, 535d xDrive, M5, 550i, 550i xDrive, and 535d sedans. The affected vehicles have an inboard lower anchor for child restraints on the left rear seat that may have been bent downwards, preventing the child seat from fully engaging both lower anchors. As such, these vehicles may fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 225, "Child Restraint Anchorage Systems."
Consequence: If the child seat is not properly attached to the lower anchors, it can increase the child's risk of injury in the event of a crash.
Remedy: BMW will notify owners, and dealers will inspect and, if necessary, repair the inboard lower anchor on the left rear seat, free of charge. The recall began on December 28, 2015. Owners may contact BMW customer service at 1-800-525-7417.
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.