U.S. regulators upgrade GM truck throttle probe

Federal safety regulators said they have upgraded a probe into more than 3 million pickup trucks and sport utility vehicles built by General Motors Corp. because of an alleged sticking throttle problem linked to dozens of accidents. In a monthly summary of its vehicle defect investigations, the U.S. National Highway Traffic Safety Administration also said it was intensifying an investigation into allegedly faulty tire air valves on 879,103 F-series Super Duty trucks and full-size Econoline vans manufactured by Ford Motor Co. . In both cases, the agency said it was upgrading its probe of the vehicles to an engineering analysis, a step that often precedes a potentially costly recall. NHTSA said its investigation into GM's vehicles involved the throttles on 3.1 million Chevrolet Silverado and GMC Sierra pickups and Chevrolet Tahoe, Suburban, Avalanche, GMC Yukon, Yukon XL and Cadillac Escalade SUVs from the 1999 to 2002 model years. "The blade in the throttle body can stick in the closed position or less frequently in a partially open position," the agency said. "Excess pedal force required to free a stuck throttle can result in accelerator overshoot and vehicle surge, possibly resulting in a crash or injury," it added. It said there had been 940 customer complaints about the problem and three minor injuries in a total of 50 reported accidents. A spokesman for GM, which has been hit by at least six recalls of its fast-selling SUVs in the past year, said the world's largest automaker was aware of NHTSA's engineering analysis and cooperating with the agency. In the case of Ford, which recalled more 112,000 F-450 and F-550 trucks because of faulty tire valves in March, NHTSA said the problem involved nearly eight times that number of vehicles. Citing 1,133 complaints, and three injuries in four crashes allegedly caused by the problem, NHTSA warned that drivers can lose control of their vehicles because of rapid tire deflation when valve stems fail. "We're aware of the investigation and continue to work with the agency," said Ford spokesman Todd Nissen. He said the agency's probe was focusing on damage that may have been caused to the tire valves in an automated assembly process at Ford's Kentucky Truck Plant. Separately, NHTSA said it had also opened an engineering analysis into reports of seat fires in Volvo's 850 series sedans and station wagons. The Swedish automaker, a unit of Ford, has long touted its image as a safety leader in the global auto industry. But NHTSA said there had been at least three reports of minor injuries, and 17 legal claims, over seat fires or the risk of seat fires in the 850 series vehicles. The alleged defect stems from problems with the power seat motor, heater element, thermostat or grounding of the seat wiring harness assemblies, NHTSA said. "We are fully cooperating with NHTSA on this matter. A team of Volvo Swedish and American engineers is in the process of thoroughly analyzing the situation," Volvo spokesman Bill Shapiro said.