ODI upgraded this investigation at the conclusion of PE04-080.the alleged defect involves the failure of the steering knuckle at the lower ball joint boss, resulting in a separation of the lower ball joint from the knuckle.a lower ball joint separation could result in a loss of steering and/or a disabled vehicle. It appears that the fractures of H2 steering knuckles can be attributed to wheel/tire collision forces being transferred directly to the steering knuckle.the original knuckle design appears to be sufficient for the H2 application.evidence from inspected vehicles, photographs, police reports and edr data indicates collision impact events placed stress on the steering knuckle causing it to fracture.further use of Agency resources does not appear to be warranted.the closing of this investigation does not constitute a finding by NHTSA that no safety-related defect exists with regard to the subject component.the Agency reserves the right to take further action on this issue if warranted.