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2017 Nissan Titan

Owner reports · Recalls · Investigations

More warning signs than most Titan years

Owner complaints for the 2017 Nissan Titan are substantially higher than the model-year median of 46.

About this comparison →

When problems were reported

Mileage at the reported incident

77 reports with mileage · 110 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.

  • Engine. Review the 98 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Electrical System. Review the 31 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Power Train. Review the 26 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →

NHTSA owner reports · September 18, 2026 snapshot.

5 crash reports9 fire reports4 injury reports

What owners actually said

187 reports
Mileage unknown · Nov 17, 2023
Engine

Always kept on maintenance and used good quality fuel for life of this Titan. Was driving and started to get a misfire and shutter. The truck eventually shut off and would not crank over. Had towed to a shop and found metal shavings in oil pan. Engine required rotating assembly replaced and block machining. Shop confirmed that t…

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Always kept on maintenance and used good quality fuel for life of this Titan. Was driving and started to get a misfire and shutter. The truck eventually shut off and would not crank over. Had towed to a shop and found metal shavings in oil pan. Engine required rotating assembly replaced and block machining. Shop confirmed that this has happened to multiple of this model Titan with this engine.

NHTSA ODI #11555728

Mileage unknown · Nov 17, 2023
Engine

At 127,000 miles my crank shaft broke into driving down the road, Nissan USA would not cover engine damage under warranty, was quoted 26,000 dollars for a new engine from Nissan service department and Joe machens Nissan located in Columbia Missouri, truck sat until I could cover cost for a used engine from a junk yard, after eve…

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At 127,000 miles my crank shaft broke into driving down the road, Nissan USA would not cover engine damage under warranty, was quoted 26,000 dollars for a new engine from Nissan service department and Joe machens Nissan located in Columbia Missouri, truck sat until I could cover cost for a used engine from a junk yard, after everything installed cost for replacement engine was 11,000 dollars

NHTSA ODI #11555616

Mileage unknown · Nov 17, 2023
Engine

Crankshaft broke in half driving 70mph down the highway without warning. Engine is seized at only 74k miles, Nissan refusing to accept responsibility and assist with repair that costs more than what the truck is worth

NHTSA ODI #11555610

Mileage unknown · Nov 12, 2023
Electrical SystemPower TrainService Brakes

There has been multitude of this issue if you search the titanxd forums. Same thing happens to everyone. ABS, traction control, and the 4wd warning flashes on the dash. After this happens, it changes the characteristics of how the truck drives. Rapid shift, high RPM shifts, which are extremely hard to control on the highway. Al…

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There has been multitude of this issue if you search the titanxd forums. Same thing happens to everyone. ABS, traction control, and the 4wd warning flashes on the dash. After this happens, it changes the characteristics of how the truck drives. Rapid shift, high RPM shifts, which are extremely hard to control on the highway. Also mentioning the ABS brake not working. Nissan has been changing out transfer cases because of this. The vehicle is extremely dangerous cause of these issues. I hope this makes headway to Nissan Corporate.

NHTSA ODI #11554744

Mileage unknown · Nov 7, 2023
Engine

Crankshaft snapped in half, without warning while 70mph. Nissan refusing to repair, truck only has 73k miles. Regular maintenance performed.

NHTSA ODI #11554072

Mileage unknown · Oct 17, 2023
Engine

On Friday, Oct. 6, 2023 I was driving my 2017 Nissan Titan Turbo XD that I just purchased in December 2022, it just lost power and stopped on the highway in the dark. I was able to get it to the shoulder and waited 3 hours for a tow truck. This happened on a deserted road in Washington state. I was able to get a rental car fo…

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On Friday, Oct. 6, 2023 I was driving my 2017 Nissan Titan Turbo XD that I just purchased in December 2022, it just lost power and stopped on the highway in the dark. I was able to get it to the shoulder and waited 3 hours for a tow truck. This happened on a deserted road in Washington state. I was able to get a rental car for the weekend, but the only technician qualified to look at my truck couldn't do so until Wednesday the 11th. The diagnosis was metal shavings in my engine oil, meaning I needed a complete new engine. The cost is $31,400 - and the truck cost me $37,000. Upon doing some research, I have found that the diesel fuel pump, the cp4, that comes in the Cummins diesel engine that was put into the Nissan Titans from 2016-2019 was not mean to have US diesel run through it. Only European diesel, which is more lubricated than diesel in the US. This cp4 need for lubrication makes it break apart and seize your engine up when used with US diesel. This is a known issue with the Nissan titan XD Turbo, and Nissan stopped making the truck in 2019 partly because of this issue. There has been no recall on the engine or the truck, and I could have easily been killed or seriously injured when my truck just stopped in the middle of the dark with no warning. No lights came on, nothing. I take meticulous care of my vehicles and as an Army Captain stationed at Fort Lewis, am well aware that routine maintenance is imperative. There was nothing that alerted my previous service technicians nor myself as to the danger that this truck contains. It's a ticking time bomb and needs to be taken out of use by Nissan, and their consumers compensated. How long until someone is killed due to the defect?

NHTSA ODI #11550436

Mileage unknown · Aug 31, 2023
Electrical SystemEnginePower Train

Driving at normal highway speed with my family vehicle shaked violently and stalled while in the middle lane of highway.I was nearly hit and crashed trying to coast to shoulder. I was towed to Nissan dealership and was told crankshaft broken in 2 peices. I’ve done research in this 5.0 Cummins diesel engine and come to find out t…

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Driving at normal highway speed with my family vehicle shaked violently and stalled while in the middle lane of highway.I was nearly hit and crashed trying to coast to shoulder. I was towed to Nissan dealership and was told crankshaft broken in 2 peices. I’ve done research in this 5.0 Cummins diesel engine and come to find out this is a very common failure due to faulty wiring harness that provides power to injectors.I’ve contacted corporate Nissan to report problem with no help.There is YouTube videos on this common unsafe problem

NHTSA ODI #11541880

Mileage unknown · Aug 18, 2023
Fuel/propulsion System

Lift pump failure. Part # 16400-EZ40B. This part has been replaced by dealer three times in the past year. Seems to last for about 8K-10K miles or so. Vehicle won't start when lift pump goes out just a warning of "low fuel pressure". Then has to be towed to dealer.

NHTSA ODI #11539417

Mileage unknown · Jul 31, 2023
Electrical SystemEngineFuel/propulsion System

Vehicle is terrible. Truck is in the shop every 2-3 months due to engine or electrical issues and constantly causing me hundreds if not thousands of dollars every time. I will never buy a Nissan product ever again.

NHTSA ODI #11535405

Mileage unknown · Jul 18, 2023
Electrical SystemEngine

I received a recall notice back in Sept 2019 (19V-495 ). I went to Antwerpen Nissan (Woodlawn, MD ) and they eroneously closed my recall ticket without completing the work. This was the second time that dealership falsified documents. Antwerpen Nissan said that they didn't see anything wrong with the wire harness. I've been hav…

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I received a recall notice back in Sept 2019 (19V-495 ). I went to Antwerpen Nissan (Woodlawn, MD ) and they eroneously closed my recall ticket without completing the work. This was the second time that dealership falsified documents. Antwerpen Nissan said that they didn't see anything wrong with the wire harness. I've been having electrical problems sporadically since 2019. The problems are getting worse. My console / touch screen system is rebooting on its own while I am driving. I am still experiencing loss of power, LED driving lights will turn on and off while driving. Draining battery ( was replaced once at the dealership ). Antwerpen of Owings Mills was the last to investigate this issue. This was just before my factory warrantee expired. They replaced the radio. Electronic issues remained. I phoned Nissan USA and tried working with Nissan Rep "CHRIS";... Who refused to approve the safety repair. Feb. 2023, Antwerpen Nissan Owings Mills Rep. John said that he would re-investigate the safety recall;... But at my expense;.. Even though the investigation was initiated prior to the factory warrantee expiring. I need my vehicle to transport me safely to and from the Hospital for my cancer treatments / exams. I don't feel safe driving that vehicle,

NHTSA ODI #11532980

Official recalls

3

19V495000 · Electrical System:alternator/generator/regulator; Electrical System:wiring

Jun 26, 2019

Nissan North America, Inc. (Nissan) is recalling certain 2017-2019 gasoline, light duty, Titan vehicles. The alternator harness may have been damaged during the engine installation process, possibly resulting in an electrical short.

Consequence & remedy

Consequence: An electrical short may cause an engine stall, increasing the risk of a crash. In addition, it increases the risk of a fire.

Remedy: Nissan will notify owners, and dealers will inspect the alternator harness for the proper routing and any damage. The harness will be clipped into the correct position or replaced as necessary, free of charge. The recall began August 8, 2019. Owners may contact Nissan customer service at 1-800-867-7669.

Additional source detail variants (2)

Electrical System:wiring

Nissan North America, Inc. (Nissan) is recalling certain 2017-2019 gasoline, light duty, Titan vehicles. The alternator harness may have been damaged during the engine installation process, possibly resulting in an electrical short.

Consequence: An electrical short may cause an engine stall, increasing the risk of a crash. In addition, it increases the risk of a fire.

Remedy: Nissan will notify owners, and dealers will inspect the alternator harness for the proper routing and any damage. The harness will be clipped into the correct position or replaced as necessary, free of charge. The recall began August 8, 2019. Owners may contact Nissan customer service at 1-800-867-7669.

Electrical System:alternator/generator/regulator

Nissan North America, Inc. (Nissan) is recalling certain 2017-2019 gasoline, light duty, Titan vehicles. The alternator harness may have been damaged during the engine installation process, possibly resulting in an electrical short.

Consequence: An electrical short may cause an engine stall, increasing the risk of a crash. In addition, it increases the risk of a fire.

Remedy: Nissan will notify owners, and dealers will inspect the alternator harness for the proper routing and any damage. The harness will be clipped into the correct position or replaced as necessary, free of charge. The recall began August 8, 2019. Owners may contact Nissan customer service at 1-800-867-7669.

18V240000 · Equipment:other:labels

Apr 16, 2018

Nissan North America, Inc. (Nissan) is recalling certain 2016-2018 Nissan Titan, 2016 and 2018 Nissan Titan XD vehicles. Accessories installed on these vehicles reduced the load carrying capacity, however, a Load Carrying Capacity modification label was not installed, possibly allowing the vehicle to be overloaded. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 110, "Tire Selection and Rims."

Consequence & remedy

Consequence: An overloaded vehicle can increase the risk of a crash.

Remedy: Nissan will notify owners and provide a new modification label, with installation instructions, free of charge. The recall began on June 4, 2018. Owners may contact Nissan customer service at 1-800-867-7669.

17V268000 · Seat Belts:rear/other

Apr 24, 2017

Nissan North America, Inc. (Nissan) is recalling certain 2016-2017 Nissan Titan Crew Cab and Titan XD Crew Cab vehicles. In the event of a crash, the rear seatbelt assembly may not adequately protect the occupant's head, allowing it to contact the D-ring bolt trim cap. As such, these vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) number 201, "Occupant Protection in Interior Impact."

Consequence & remedy

Consequence: If the occupant's head contacts the D-ring bolt trim cap during a crash, there is an increased risk of injury.

Remedy: Nissan will notify owners, and dealers will install energy absorbing material to the C-Pillar Finishers and replace the Seatbelt Bolt and Bolt Cap, free of charge. The recall began September 19, 2017. Owners may contact Nissan customer service at 1-800-647-7261.

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

2

PE23020 · Loss Of Motive Power Due To Broken Crankshaft With No Ability To Restart.

Opened Nov 15, 2023 · Closed Jun 27, 2025

Status: closed (inferred from source dates) · Engine; Engine And Engine Cooling:engine:diesel

On November 15, 2023, the Office of Defects Investigation (ODI) opened Preliminary Evaluation PE23020 to investigate allegations of loss of motive power in model year (MY) 2016 through 2019 Nissan Titan XD trucks equipped with 5.0L Cummins diesel engines.  The complaints allege the condition was due to a failure of the engine crankshaft.  The purpose of the investigation was to understand the scope, frequency, and safety related consequence of the alleged defect. During the investigation, it was found that the subject vehicles can experience a loss of motive power due to a failure of the crankshaft main bearings which can lead to a fractured crankshaft. This resulted in a loss of motive power and an inability to restart. An analysis of all complaint sources shows many vehicles exhibit knocking, vibration, malfunction indicator lamp (MIL) warnings, and/or poor engine performance prior to a total failure.  Some consumers report driving their truck in for repairs only to be diagnosed with a failed crankshaft.  ODI has not identified any injuries or fires attributable to this failure. ODI is aware of one complaint alleging a non-injury crash involving a curb strike.  ODI is also aware of complaints of overheating starter motors and melted starter motor wiring occurring after prolonged attempts to start engines that have suffered a broken crankshaft. In its response to ODI's January 26, 2024 information request letter, Nissan provided information detailing several material and process changes involved in the production of the subject vehicle’s engine.These changes appear to coincide with incremental improvements in failure rates but there is no indication that a single factor was the primary cause of the failures. Analysis of ODI consumer complaints and manufacturer provided data found that failure rates decreased progressively for each model year. Review of failure mileage found that 50% of the failures occurred by 60,000 miles with a significant decrease in failures after 80,000 miles. Assuming average yearly mileage driven, the newest model year trucks (2019) would be near or past peak failure mileage. Given the low failure rate, the observable warnings available to the driver, and much of the fleet being past peak failure mileage, ODI is closing this Preliminary Evaluation with no further action.  The closing of the investigation does not constitute a finding by NHTSA that a defect does not exist, and NHTSA will take further action if warranted by future circumstances. To review the ODI reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

Additional source detail variants (2)

Engine And Engine Cooling:engine:diesel

On November 15, 2023, the Office of Defects Investigation (ODI) opened Preliminary Evaluation PE23020 to investigate allegations of loss of motive power in model year (MY) 2016 through 2019 Nissan Titan XD trucks equipped with 5.0L Cummins diesel engines.  The complaints allege the condition was due to a failure of the engine crankshaft.  The purpose of the investigation was to understand the scope, frequency, and safety related consequence of the alleged defect. During the investigation, it was found that the subject vehicles can experience a loss of motive power due to a failure of the crankshaft main bearings which can lead to a fractured crankshaft. This resulted in a loss of motive power and an inability to restart. An analysis of all complaint sources shows many vehicles exhibit knocking, vibration, malfunction indicator lamp (MIL) warnings, and/or poor engine performance prior to a total failure.  Some consumers report driving their truck in for repairs only to be diagnosed with a failed crankshaft.  ODI has not identified any injuries or fires attributable to this failure. ODI is aware of one complaint alleging a non-injury crash involving a curb strike.  ODI is also aware of complaints of overheating starter motors and melted starter motor wiring occurring after prolonged attempts to start engines that have suffered a broken crankshaft. In its response to ODI's January 26, 2024 information request letter, Nissan provided information detailing several material and process changes involved in the production of the subject vehicle’s engine.These changes appear to coincide with incremental improvements in failure rates but there is no indication that a single factor was the primary cause of the failures. Analysis of ODI consumer complaints and manufacturer provided data found that failure rates decreased progressively for each model year. Review of failure mileage found that 50% of the failures occurred by 60,000 miles with a significant decrease in failures after 80,000 miles. Assuming average yearly mileage driven, the newest model year trucks (2019) would be near or past peak failure mileage. Given the low failure rate, the observable warnings available to the driver, and much of the fleet being past peak failure mileage, ODI is closing this Preliminary Evaluation with no further action.  The closing of the investigation does not constitute a finding by NHTSA that a defect does not exist, and NHTSA will take further action if warranted by future circumstances. To review the ODI reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

Engine

On November 15, 2023, the Office of Defects Investigation (ODI) opened Preliminary Evaluation PE23020 to investigate allegations of loss of motive power in model year (MY) 2016 through 2019 Nissan Titan XD trucks equipped with 5.0L Cummins diesel engines.  The complaints allege the condition was due to a failure of the engine crankshaft.  The purpose of the investigation was to understand the scope, frequency, and safety related consequence of the alleged defect. During the investigation, it was found that the subject vehicles can experience a loss of motive power due to a failure of the crankshaft main bearings which can lead to a fractured crankshaft. This resulted in a loss of motive power and an inability to restart. An analysis of all complaint sources shows many vehicles exhibit knocking, vibration, malfunction indicator lamp (MIL) warnings, and/or poor engine performance prior to a total failure.  Some consumers report driving their truck in for repairs only to be diagnosed with a failed crankshaft.  ODI has not identified any injuries or fires attributable to this failure. ODI is aware of one complaint alleging a non-injury crash involving a curb strike.  ODI is also aware of complaints of overheating starter motors and melted starter motor wiring occurring after prolonged attempts to start engines that have suffered a broken crankshaft. In its response to ODI's January 26, 2024 information request letter, Nissan provided information detailing several material and process changes involved in the production of the subject vehicle’s engine.These changes appear to coincide with incremental improvements in failure rates but there is no indication that a single factor was the primary cause of the failures. Analysis of ODI consumer complaints and manufacturer provided data found that failure rates decreased progressively for each model year. Review of failure mileage found that 50% of the failures occurred by 60,000 miles with a significant decrease in failures after 80,000 miles. Assuming average yearly mileage driven, the newest model year trucks (2019) would be near or past peak failure mileage. Given the low failure rate, the observable warnings available to the driver, and much of the fleet being past peak failure mileage, ODI is closing this Preliminary Evaluation with no further action.  The closing of the investigation does not constitute a finding by NHTSA that a defect does not exist, and NHTSA will take further action if warranted by future circumstances. To review the ODI reports cited in the Closing Resume ODI Report Identification Number document, go to NHTSA.gov.

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.