NHTSA owner reports · September 18, 2026 snapshot.
Power Train complaints
14 reportsClear category filterMileage unknown · Jul 6, 2024
Power TrainSteeringUnknown Or Other
MERCEDES DEALER NOTES : 07/19/2022 CLIENT STATES STEERING IS STIFF. STARTED ABOUT 1 TO 2 MONTHS AGO AND WOULD SHOW UP ONCE AND AWHILE. WHEN IT WOULD ACT UP WOULD NOT DRIVE IT AND IT WOULD LOCK THE STEERING . THIS HAPPENED MULTIPLE TIMES, WITH ACCIDENT HAZARD. WE DID THE BELOW WORK. ELECTRIC POWER STEERING RACK FAULTY REPLACE COM…
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MERCEDES DEALER NOTES : 07/19/2022 CLIENT STATES STEERING IS STIFF. STARTED ABOUT 1 TO 2 MONTHS AGO AND WOULD SHOW UP ONCE AND AWHILE. WHEN IT WOULD ACT UP WOULD NOT DRIVE IT AND IT WOULD LOCK THE STEERING . THIS HAPPENED MULTIPLE TIMES, WITH ACCIDENT HAZARD. WE DID THE BELOW WORK. ELECTRIC POWER STEERING RACK FAULTY REPLACE COMPLETE ELECTRIC POWER STEERING RACK. WHICH COST US OVER $3000. NOW WE HAVE SIMILIAR PROBLEM STEERING IS TIGHT AGAIN, MAKING FLAPPING NOISE, DEALER RECOMMENDED REPLACEMENT OF POWER STEERING RACK, GEAR BOX 07/02/24 , MERCEDES HAS RECALL ON MANY MODELS DURING YEAR 2015-2018 FOR electric power steering systems, Mercedes says the cars use electric power steering systems that May have soldered contacts that weren't soldered correctly inside the control units. The bad contacts can cause a sudden loss of power steering while driving, causing serious problems if driving around a curve or at slow speeds.
NHTSA ODI #11599546
Mileage unknown · Jan 26, 2023
Power Train
Occasionally the car will lurch forward when coming to a stop. As you come to a stop it tries to propel the car forward as you are breaking and coming to a stop. Happens rarely but when it does it's a big safety concern.
NHTSA ODI #11503744
Mileage unknown · Aug 28, 2022
Power Train
Vehicle stopped suddenly and would not restart. Needs a new $17k drive unit and is out of warranty. Drive unit failed due to faulty design where coolant contaminated the electric motor. Vehicle only has 40k miles. The drive unit was built by Tesla for Mercedes. Tesla also built the same unit for Toyota for the electric Rav4. …
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Vehicle stopped suddenly and would not restart. Needs a new $17k drive unit and is out of warranty. Drive unit failed due to faulty design where coolant contaminated the electric motor. Vehicle only has 40k miles. The drive unit was built by Tesla for Mercedes. Tesla also built the same unit for Toyota for the electric Rav4. Toyota recalled their units free of charge for customers. Mercedes is aware of this issue and refuses to extend the warranty or recall the roughly 4000 B250E cars that they sold in the USA from 2014-2017.
NHTSA ODI #11481618
36,000 miles · Nov 20, 2019
Electrical SystemEnginePower Train
THIS MB MODEL HAS AN ELECTRIC MOTOR THAT FAILS AT AROUND 35000 TO 40000 MILES, AND MAKES THE VEHICLE TO STOP SUDDENLY CAUSING SERIOUS RISKS TO THE DRIVER IF THIS HAPPENS IN ANY MAIN HIGHWAY. TWO WEEKS AGO MY WIFE WAS DRIVING NORTHBOUND AT THE FAST LANE OF THE PALMETTO EXPRESSWAY , IN MIAMI FL, WHEN THE CAR STOPPED GIVING NO TIM…
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THIS MB MODEL HAS AN ELECTRIC MOTOR THAT FAILS AT AROUND 35000 TO 40000 MILES, AND MAKES THE VEHICLE TO STOP SUDDENLY CAUSING SERIOUS RISKS TO THE DRIVER IF THIS HAPPENS IN ANY MAIN HIGHWAY. TWO WEEKS AGO MY WIFE WAS DRIVING NORTHBOUND AT THE FAST LANE OF THE PALMETTO EXPRESSWAY , IN MIAMI FL, WHEN THE CAR STOPPED GIVING NO TIME TO AVOID COMING TRAFFIC. FORTUNATELY ONE FDOT RANGER WAS DRIVING SAME WAY AND PROTECT MY WIFE TURNING ON ITS EMERGENCY LIGHTS WHILE THEY WAIT FOR A TOW TRUCK TO ARRIVE. THIS MODEL OF MB IS ASSEMBLED WITH A TESLA MOTOR THAT HAS BEEN PROVEN TO FAIL, BUT TESLA HAS TAKEN FAST ACTION TO AVOID INCONVENIENCES TO ITS CUSTOMERS. MB HAS DOING NOTHING TO ADVICE ITS CUSTOMERS ON THIS CRITICAL ISSUE, PUTTING ON RISK ON A DAILY BASIS ALL DRIVERS THAT RIDE TIS MB MODEL. I FIGURE IF OTHERS ARE FACING SIMILAR ISSUES, IT WOULD BE GOOD TO GET A RECALL SET UP IF MB DOES NOT STEP UP TO THE PLATE. IT TOOK FOUR YEARS FOR THESE ISSUES TO SHOW UP NEAR THE END OF MY WARRANTY, AND SINCE THE CARS REMAIN ESSENTIALLY THE SAME THROUGH THE 2017 MODELS, WE MAY EXPECT TO SEE OTHERS MODEL YEARS SHOW THE SAME ISSUES AS THE END OF THEIR WARRANTIES COME UP. I HOPE NOT, FOR EVERYONE ELSE BUT BEST BE PREPARED. MY VEHICLE CAN BEEN INSPECTED AT THE MERCEDES BENZ OF MIAMI DEALER WHERE REPAIR ARE UNDERWAY.
NHTSA ODI #11281313
3,000 miles · Apr 8, 2016
Power Train
CAR STALLED WHILE GOING ON EXPRESSWAY AT 30 MPH. COMPLETE LOSS OF POWER. HAD TO PULL OVER AND POWER OFF THE CAR. RESTART OF THE CAR AFTER A WHILE AND EVERYTHING WAS BACK TO NORMAL.
NHTSA ODI #10854506
1,200 miles · Oct 17, 2015
Power Train
WHILE THE CAR WAS IN MOTION, THE ENGINE HAS SWITCHES OFF AND THE CAR GOES IN NEUTRAL. THIS HAS HAPPENED ALREADY 3 TIMES (APPROXIMATELY ONCE PER MONTH). IT HAS HAPPENED WHILE ON THE INTERSTATE, WHILE DRIVING ON A SMALL ROAD, AND WHILE APPROACHING A STOP SIGN. THE CAR CAN BE RESTARTED NORMALLY. WE HAVE HAD THE CAR AT THE MERCEDES …
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WHILE THE CAR WAS IN MOTION, THE ENGINE HAS SWITCHES OFF AND THE CAR GOES IN NEUTRAL. THIS HAS HAPPENED ALREADY 3 TIMES (APPROXIMATELY ONCE PER MONTH). IT HAS HAPPENED WHILE ON THE INTERSTATE, WHILE DRIVING ON A SMALL ROAD, AND WHILE APPROACHING A STOP SIGN. THE CAR CAN BE RESTARTED NORMALLY. WE HAVE HAD THE CAR AT THE MERCEDES DEALER IN SEPTEMBER 2015, AND THE TRIED TO FIX THE PROBLEM BY INSTALLING THE LATEST SOFTWARE. HOWEVER, IT JUST HAPPENED AGAIN. THIS CAR IS NOT SAFE TO DRIVE THE LAST TIME THE CAR STALLED WHILE DRIVING, WE LET THE CAR COME TO A COMPLETE STOP, WITHOUT TOUCHING ANYTHING BUT THE BREAK, AND MAKE A PICTURE OF THE INSTRUMENT PANEL. THIS PICTURE IS ATTACHED TO THE REPORT TO DOCUMENT THE INCIDENCE.
NHTSA ODI #10783052
1,600 miles · Oct 11, 2015
EngineFuel/propulsion SystemPower Train
MY B-CLASS ELECTRIC HAD A SUDDEN LOSS OF POWER. HERE'S THE DETAILS: LEFT THE HOUSE IN SAN DIEGO AT 7:00 AM. OUTSIDE TEMPERATURE ABOUT 75+DEGREES. ABOUT 1 MILE FROM THE START, I BRAKED SLIGHTLY TO MAINTAIN SPEED OF ABOUT 25 MPH, COASTED TOWARDS AND UPHILL, PUT MY FOOT ON THE ACCELERATOR TO MAINTAIN SPEED AND THERE WAS NO P…
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MY B-CLASS ELECTRIC HAD A SUDDEN LOSS OF POWER. HERE'S THE DETAILS: LEFT THE HOUSE IN SAN DIEGO AT 7:00 AM. OUTSIDE TEMPERATURE ABOUT 75+DEGREES. ABOUT 1 MILE FROM THE START, I BRAKED SLIGHTLY TO MAINTAIN SPEED OF ABOUT 25 MPH, COASTED TOWARDS AND UPHILL, PUT MY FOOT ON THE ACCELERATOR TO MAINTAIN SPEED AND THERE WAS NO POWER-JUST COASTING. THERE WAS NO UNUSUAL SOUND AND NO WARNING DISPLAYED. THE CAR APPEARED NORMAL EXCEPT THE GUAGE WAS SHOWING FULL REGENERATIVE BRAKING WHILE THE CAR WAS COASTING. TRANSMISSION WAS IN D-AUTO. POWER STEERING WORKED, AC AND RADIO WERE STILL ON. I BROUGHT IT TO A STOP. PUSHED THE BUTTON TO TURN IT OFF. AT THAT TIME ALL THE LIGHTS ON THE DASH LIT UP. I PUSHED IT AGAIN AND THE CAR WAS BACK TO NORMAL WITH THE INDICATOR SHOWING ZERO BETWEEN REGENERATION AND DISCHARGE. I FINISHED THE DRIVE WITHOUT FURTHER INCIDENT. MILEAGE: 1620 MILES PURCHASED: JUNE 2015 MFG DATE: 4/15 TOOK THE CAR TO THE DEALER TWO HOURS LATER AND TOLD THEM ABOUT THE PROBLEM AND THAT THE FORUM SAYS THERE IS A CODE UPDATE AVAILABLE. WAITED THERE FOR 3 HOURS. THEIR PAPER WORK SAYS: 1639 541011, 540991, 540992. PROGRAMMED POWER TRAIN CONTROL UNIT. PERFORMED SHORT TEST; NO RELEVANT FAULT CODES. CHECKED POWER TRAIN CONTROL UNIT FOR SOFTWARE UPDATES. UPDATE WAS AVAILABLE. PROGRAMMED AND CODED POWER TRAIN CONTROL UNIT. COMPLETE.
NHTSA ODI #10781331
3,300 miles · Oct 8, 2015
Electrical SystemEnginePower Train
ON 10-5-15, MY 2015 MERCEDES B CLASS WITH 3300 MILES DECIDED TO LOSE ALL POWER IN THE MIDDLE OF 101 IN RUSH HOUR TRAFFIC. LUCKILY TRAFFIC WAS MOVING AT 15MPH, I HAD TO COMPLETELY STOP THE CAR IN THE MIDDLE LANE. PUT THE CAR IN PARK, SHUT IT OFF AND RESTART TO REGAIN POWER. THERE WERE NO CHECK ENGINE LIGHT OR SIGNS THAT THE CA…
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ON 10-5-15, MY 2015 MERCEDES B CLASS WITH 3300 MILES DECIDED TO LOSE ALL POWER IN THE MIDDLE OF 101 IN RUSH HOUR TRAFFIC. LUCKILY TRAFFIC WAS MOVING AT 15MPH, I HAD TO COMPLETELY STOP THE CAR IN THE MIDDLE LANE. PUT THE CAR IN PARK, SHUT IT OFF AND RESTART TO REGAIN POWER. THERE WERE NO CHECK ENGINE LIGHT OR SIGNS THAT THE CAR WAS BROKEN, I JUST SIMPLY LOST ALL DRIVE POWER EVEN THOUGH I WAS IN D. IT WAS SCARY AS I WAS ON THE 101 AT ABOUT 4PM. THIS ALSO HAPPENED AT ANOTHER WHEN I FIRST GOT THE CAR, PLEASE GET MERCEDES TO FIX THIS BEFORE I GET REAR-ENDED AND CRUSHED.
NHTSA ODI #10780926
1,280 miles · Oct 1, 2015
Fuel/propulsion SystemPower TrainVehicle Speed Control
DRIVING ON THE FREEWAY AT 65MPH, EXPERIENCED COMPLETE AND SUDDEN LOSS OF DRIVE/POWER. CAR CHARGE WAS AROUND 1/2 FULL. HAD TO PULL TO THE SHOULDER AS THE CAR ROLLED TO A COMPLETE STOP. FINDING LOTS OF OTHER REPORTS ONLINE, DEALER HAS BEEN UNABLE TO DETERMINE THE ROOT CAUSE AFTER 1 WEEK. DEALER REPORTED OTHER SIMILAR INCIDENTS…
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DRIVING ON THE FREEWAY AT 65MPH, EXPERIENCED COMPLETE AND SUDDEN LOSS OF DRIVE/POWER. CAR CHARGE WAS AROUND 1/2 FULL. HAD TO PULL TO THE SHOULDER AS THE CAR ROLLED TO A COMPLETE STOP. FINDING LOTS OF OTHER REPORTS ONLINE, DEALER HAS BEEN UNABLE TO DETERMINE THE ROOT CAUSE AFTER 1 WEEK. DEALER REPORTED OTHER SIMILAR INCIDENTS FROM OTHER DRIVERS.
NHTSA ODI #10778913
1,000 miles · Sep 21, 2015
Fuel/propulsion SystemPower Train
I WAS DRIVING ON THE 91 FREEWAY IN ANAHEIM CA WHEN MY BRAND NEW (APPROXIMATELY 1000 MILES ON THE ODOMETER) 2015 MB ALL ELECTRIC AUTOMOBILE BEGAN TO DECELERATE. MY FOOT WAS ON THE ACCELERATOR AS I LOST ALL POWER TO THE ENGINE. THE BATTERY WAS FULLY CHARGED. THE RADIO AND ALL OF THE ELECTRONIC INTERIOR FEATURES WERE INTACT. I WAS…
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I WAS DRIVING ON THE 91 FREEWAY IN ANAHEIM CA WHEN MY BRAND NEW (APPROXIMATELY 1000 MILES ON THE ODOMETER) 2015 MB ALL ELECTRIC AUTOMOBILE BEGAN TO DECELERATE. MY FOOT WAS ON THE ACCELERATOR AS I LOST ALL POWER TO THE ENGINE. THE BATTERY WAS FULLY CHARGED. THE RADIO AND ALL OF THE ELECTRONIC INTERIOR FEATURES WERE INTACT. I WAS IN THE 3RD LANE OF TRAFFIC (OUT OF 5). LUCKILY THE TRAFFIC WAS LIGHT AS I PULLED OVER TO THE SIDE OF THE FREEWAY AND THE CAR CAME TO A COMPLETE STOP. I WAS QUITE UNNERVED BY THE INCIDENT BUT THE CAR STARTED UP AND I CONTINUED MY COMMUTE TO WORK UNEVENTFULLY. I TOOK MY VEHICLE TO THE MERCEDES DEALERSHIP AND THEY EVALUATED THE CAR. THEY COULD NOT REPLICATE THE EVENT AND COULD NOT FIND AN ANOMALY IN THE ON BOARD COMPUTERS. I PRESENTED TESTIMONY FROM THIS VERY WEBSITE DISCLOSING 7 OTHER RECENT SIMILAR EVENTS IN THIS MODEL CAR. I ADVISED THE DEALERSHIP THAT I WAS NOT TAKING POSSESSION OF THE AUTO UNLESS SOMETHING WAS DONE. THEY PRESENTED THE INFORMATION TO MERCEDES BENZ/TESLA TECHNICAL SUPPORT. THE GATEWAY POWERTRAIN CONTROL UNIT WAS REPLACED. I EXPRESSED MY CONCERN TO THE MB DEALERSHIP THAT THIS MAYBE A SYSTEMIC PROBLEM, GIVEN THE NUMBER OF COMPLAINTS IN SUCH A SHORT PERIOD OF TIME. THE DEALERSHIP REPRESENTATIVE EXPRESSED SYMPATHY WITH MY SITUATION BUT DECLARED THAT THIS IS SOMETHING WE SHOULD TAKE UP WITH DAIMLER-BENZ. THE DEALERSHIP IS A SEPARATE ENTITY WHICH ONLY BUYS/SELLS AND PROVIDES MAINTENANCE FOR MB AUTOMOBILES. I EXPRESSED THAT THIS DEFECT HAS ME CONCERNED EVERY TIME I ENTER A FREEWAY. THE SERVICE MANAGER COULD NOT REASSURE ME THAT THIS WILL NOT HAPPEN AGAIN. I HOPE IT DOES NOT TAKE FATALITIES BEFORE THERE IS A RECALL.
NHTSA ODI #10766546
NHTSA investigations
2DP22005 · Pedestrian Alert Sounds
Opened Jan 27, 2023 · Closed Aug 7, 2023
Status: closed (inferred from source dates) · Electrical System:propulsion System
NHTSA received a petition on or about July 18, 2022, requesting that Federal Motor Vehicle Safety Standard (FMVSS) 141 be applied to all electric and hybrid vehicles operating in the United States. The petition can be reviewed at NHTSA.gov under ODI Number 11486072. FMVSS 141 establishes performance requirements for pedestrian alert sounds for motor vehicles. The standard applies to hybrid and electric vehicles that have a gross vehicle weight rating of 4,536 KG or less or are defined as low-speed vehicles. The standard became fully applicable to all such vehicles manufactured on or after March 1, 2021.On January 27, 2023, NHTSA opened Defect Petition (DP) 22-005 to evaluate the subject matter described in the petition. On June 24, 2023 and as supplemented on June 25, 2023, the petitioner notified NHTSA he was withdrawing his petition. The petitioner indicated that, based on his review of data, there is no justification for asserting potential benefits that could be derived from actions sought by my petition. Based on the petitioner's withdrawal, DP22-005 is closed. Closure of this DP does not represent a determination by NHTSA regarding the subject matter of the petition.
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.