The Office of Defects Investigation (ODI) opened PE21-021 on October 14, 2021, to investigate incidents alleging a stall/loss of motive power as a result of high-pressure fuel pump failures in certain model year (MY) 2019-2020 Ram 2500, 3500, 4500, and 5500 heavy duty trucks equipped with 6.7L Cummins turbodiesel engines. During the investigation, ODI sought to determine if the related defect allegation was limited in scope to the recalled population. After review of information request response materials from both FCA and BMW, NHTSA determined that sufficient information to identify a comprehensive recall population could not be produced by FCA and BMW.During the investigation FCA filed recalls 22V406, 22E048, 22V767, and 22E087 which include vehicles not identified in the initial subject population by ODI. ODI also received recall 21V586, involving loss of motive power due to failed CP4 fuel pumps on certain BMW manufactured vehicles. An information request letter response received from BMW indicated that failed pumps on their vehicles were caused by an interaction between pump internal components and US market diesel fuel, leading to increased slip and eventual particle-generating wear surface. Additional work will be done to identify whether a similar root cause is associated with the FCA recalled population and if similar wear dynamics occur on pumps supplied to vehicle manufacturers other than those included in the recalled population.ODI has upgraded this investigation to an EA in order to 1) determine engineering specifications of internal pump components that are correlated with pump failure leading to loss of motive power or other safety related hazards, 2) identify vehicle populations equipped with alleged defective pump variants, 3) assess if vehicles equipped with alleged defective pump variants result in an unreasonable risk to motor vehicle safety and 4) gather and review any other relevant information related to high pressure fuel pump failure associated with the subject populations of recalls 21V586, 21V880, 21E094, 22V406, 22E048, 22V767, and 22E087.Review of the above information will allow NHTSA to confirm root cause and recall remedy viability, and identify and evaluate vehicle populations equipped with pump components that may pose an unreasonable risk to motor vehicle safety.The ODI reports cited above can be reviewed at: http://www-odi.nhtsa.dot.gov/owners/SearchNHTSAID using the following complaint identification numbers: 11257550, 11351441, 11361603, 11361616, 11365300, 11365426, 11365858, 11366401, 11372337, 11373793, 11374797, 11376793, 11377871, 11378173, 11384377, 11386063, 11387018, 11399710, 11402550, 11415339, 11418868, 11418870, 11427075, 11434276, 11436807, 11437226, 11437249, 11437273, 11437292, 11437294, 11437394, 11437399, 11437403, 11437405, 11437423, 11437528, 11437565, 11437579, 11437580, 11437590, 11437679, 11437744, 11437781, 11437842, 11437993, 11438006, 11438008, 11438121, 11438138, 11438155, 11438392, 11438629, 11439359, 11439879, 11440397, 11443030, 11446542, 11448163, 11453556, 11458918, 11460558, 11469337
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.
