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2016 Nissan Titan Xd

Owner reports · Recalls · Investigations

Limited comparison data

There is not enough comparable history to draw a useful model-year comparison.

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How this year compares

Owner complaints by model year

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Compare all Titan Xd years →

Counts vary with age, sales and reporting. They are not failure rates.

What owners reported most

All reported categories

Tap a category to read its complaints. One report may name several components.

When problems were reported

Mileage at the reported incident

78 reports with mileage · 119 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 128 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Power Train. Review the 42 owner reports in this category and discuss these concerns during a pre-purchase inspection. Read reports →
  • Fuel/propulsion System. Review the 31 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 reports2 fire reports2 injury reports

Engine complaints

128 reports
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Mileage unknown · Jul 3, 2024
Engine

Engine suddenly shut off while on a short run with no load and couldn’t restart. Took it to the dealership and metal shaving's in the oil pan

NHTSA ODI #11598716

Mileage unknown · Jun 21, 2024
EngineFuel/propulsion SystemPower Train

While driving my 2016 Nissan Titan XD Cummins (86,000 miles) on the highway, the engine started making a loud clacking noise, followed by a loud breaking or displacement sound. The check engine light did not come on, and the truck did not go into limp mode. Possible issues might be crankshaft or bearing failure, piston or connec…

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While driving my 2016 Nissan Titan XD Cummins (86,000 miles) on the highway, the engine started making a loud clacking noise, followed by a loud breaking or displacement sound. The check engine light did not come on, and the truck did not go into limp mode. Possible issues might be crankshaft or bearing failure, piston or connecting rod damage, or a valve train problem. The vehicle is available for inspection upon request. There were no prior warning lamps, messages, or other symptoms before this failure. The problem has not yet been inspected or confirmed by a dealer or service center.

NHTSA ODI #11595672

85,000 miles · Jun 4, 2024
Engine

The contact owns a 2016 Nissan Titan. The contact stated that the vehicle was idling rough while being started. While driving at 5 MPH, the vehicle shut off unintendedly. The vehicle failed to restart. There were no warning lights illuminated. The vehicle was towed to the local dealer, where it was diagnosed that the wiring harn…

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The contact owns a 2016 Nissan Titan. The contact stated that the vehicle was idling rough while being started. While driving at 5 MPH, the vehicle shut off unintendedly. The vehicle failed to restart. There were no warning lights illuminated. The vehicle was towed to the local dealer, where it was diagnosed that the wiring harness and engine needed to be replaced. The vehicle was not repaired. The manufacturer was contacted and opened a case. The manufacturer offered to assist with the cost of the repair. The failure mileage was approximately 85,000.

NHTSA ODI #11592324

Mileage unknown · Jun 2, 2024
Engine

Driving on the intersate with no warning lights engine began to run rough, pulled over and shut engine off. Trailered it to a local shop, they found lots of metal in the oil. I tried to start it to drive it on the trailer but the engine had sized due to catastrophic engine failure. It has 89900 miles.

NHTSA ODI #11592012

Mileage unknown · May 17, 2024
Engine

The Crankshaft snapped in at only 66k miles.

NHTSA ODI #11589398

Mileage unknown · May 7, 2024
Engine

hi, i was driving on the free way to work hauling a small 10ft. trailer and my engine started knocking Badly! i get off free way start to head home and slowly take off and rpms take off and Boom. engine done.. so spun bearings/boken crank i havnt taken engine out to inspect yet because you cant buy a new engine and used engines …

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hi, i was driving on the free way to work hauling a small 10ft. trailer and my engine started knocking Badly! i get off free way start to head home and slowly take off and rpms take off and Boom. engine done.. so spun bearings/boken crank i havnt taken engine out to inspect yet because you cant buy a new engine and used engines are 10-12k. come to find out this engine has broken crank problems. not only could i have wrecked if it had blew on free way. but now im out of a truck that insurance wont pay. and still owe 24k to the bank.. thanks. [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI #11587545

Mileage unknown · Apr 30, 2024
Engine

Engine failure -I was driving about 45-50 mph and as I was approaching a four way intersection with a stop sign approaching in my direction of travel. As I came to a stop, the engine locked up and could not be restarted. Leaving my truck dead in the middle of the road. After having it towed to a friend's shop I removed the oil …

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Engine failure -I was driving about 45-50 mph and as I was approaching a four way intersection with a stop sign approaching in my direction of travel. As I came to a stop, the engine locked up and could not be restarted. Leaving my truck dead in the middle of the road. After having it towed to a friend's shop I removed the oil pan, only to find a alot of copper colored metal shavings all throughout. I have an obd2 scan tool with live monitoring called a BlueDriver which connects via Bluetooth to my phone and allows me to monitor different sensors and checks for any trouble codes that the truck may currently have. I had this app open and was monitoring about 6 different sensors at the time. The truck never showed any signs of anything unusual or out of the ordinary. I also never had any warnings or the check engine light come on. After joining a few Facebook groups and online fourms, and I realized this was not a very rear occurrence and that many others have experienced similar engine failures as well.

NHTSA ODI #11586227

Mileage unknown · Apr 2, 2024
Engine

The engine crankshaft failed and broke in half while driving. I was driving on the New Jersey turnpike on cruise control with a trailer and a mower and all of a sudden the motor is making [XXX] noises and I lose engine power completely. This is a huge defective part and one of the main components of a motor that should not fail …

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The engine crankshaft failed and broke in half while driving. I was driving on the New Jersey turnpike on cruise control with a trailer and a mower and all of a sudden the motor is making [XXX] noises and I lose engine power completely. This is a huge defective part and one of the main components of a motor that should not fail and break in half like it did. It’s a major catastrophic failure that should be resolved with a recall. The danger and risk that involves this issue is ridiculous and it should be resolved immediately. I have kept up on my services like I should the truck has been well taken care of. After research I have seen there has been alot of people with the same issue with very low miles. Even with higher miles this issue should not happen. The cost of this repair is outrageous no vehicle owner should pay that on their own specially when they still owe a lot of money on the vehicle. There were no fatalities in my incident but there could have been and it could have been bad. The manufacturer needs to take responsibility with this issue and fix it and prevent future incidents and hopefully save a life if it occurs. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI #11580625

Mileage unknown · Feb 9, 2024
Electrical SystemEngineFuel/propulsion System

I purchased this vehicle in 2022 with 62000 miles on it for $45000, cash first newer vehicle ever paid for in cash, 1st day i drove it, check engine light for turbo failure came on, i normally put 80-100k miles on a vehicle per year, ive owned over 200 diesel vehicles in last 25 years, never have i had one stay in the shop more…

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I purchased this vehicle in 2022 with 62000 miles on it for $45000, cash first newer vehicle ever paid for in cash, 1st day i drove it, check engine light for turbo failure came on, i normally put 80-100k miles on a vehicle per year, ive owned over 200 diesel vehicles in last 25 years, never have i had one stay in the shop more than driving it. Not only does it stay in the shop, but you have to locate a shop that still has a diesel technician employed. Two turbo actuator replacements, lift pump replacement, 18 shop visits for check engine lights, 5 times in a row at buford ga nissan, drove away and light came back on before making it home. [XXX] my family and I was driving to florida , doing 55mph, No check engine lights, no noises, no warnings, motor shut down in 21 degree weather, side of [XXX] in tucker georgia for 4 hours waiting for a tow truck, only thing on screen was DEF error see dealer immediately, $550 to tow vehicle back to my house because closest dealership did NOT have a diesel tech, spent two months to find a company that would tow my truck 55 miles from gainesville georgia to roswell georgia to regal nissan, the girl called me and said it needed a starter for $900plus dollars, i laughed and said there's no way in hell a starter caused this motor to die, i informed her that if starter did Not work i was not paying, two days later she calls me back up and informs me the motor is locked up, does not know why, but pay them $178 diagnosis fee, and for $1300-$2000 they could tell me exactly what failed, if u read online, trucks like mine fail between 50000-100000 miles with no warning no nothing! i am now stuck with another $330 tow bill to pick vehicle up and store it at my shop and pray that your organization can hold NIssan accountable, Nissans recommendation was for $30000 to put the exact same unmodified garbage of a motor back in this truck, please somebody hold this company accountable!!!!!! thanks INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ODI #11570938

Mileage unknown · Feb 7, 2024
Engine

Bad crankshaft reported by dealership Only 70000 miles and well kept maintenance No warning lamps prior to failure

NHTSA ODI #11570515

Official recalls

3

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.

16V847000 · Fuel System, Diesel:storage:tank Assembly

Nov 22, 2016

Nissan North America, Inc. (Nissan) is recalling certain model year 2016 Titan Diesel XD vehicles manufactured August 7, 2015, to September 1, 2016. The affected vehicles may not have had the temporary fuel tank breather tube cap removed during the vehicle's assembly and the fuel tank breather tube may not have been connected to the bed rail. As a result, the fuel tank may not have the proper ventilation, possibly causing the fuel gauge and the distance to empty meter to both display inaccurately.

Consequence & remedy

Consequence: If the fuel gauge reads incorrectly, the vehicle can run out of fuel without the driver being aware, increasing the risk of a crash.

Remedy: Nissan will notify owners, and dealers will inspect the fuel tank breather tube, replacing the fuel tank, fuel sending unit, and/or fuel tank breather tube, as necessary, free of charge. The recall began on December 12, 2016. 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.