Prius brake problems may be tip of electronic iceberg

LOS ANGELES — A new federal investigation into braking problems with Toyota's Prius hybrid is just one in a series of possible glitches that may be linked to the vehicle's complex electronics, including headlights that fail inexplicably, records and interviews show.

Thursday, the National Highway Traffic Safety Administration (NHTSA) said it had opened a formal investigation into the 2010 model Prius after getting 124 complaints from drivers of a brief loss in braking power, which has been blamed in four crashes, two of which resulted in injuries. Toyota has said it sold 103,000 of the new 2010 Prius models in the U.S. since last May.

In a related development, Ford said it would offer owners of its Fusion and Mercury Milan hybrids a software upgrade because of similar brake complaints.

The federal probe came as Toyota said its recall-related losses would cost it $2 billion. The company has blamed its sudden-acceleration problems on floor mats that entrap its gas pedals and gas pedals that stick. But independent safety experts say they believe bugs in electronic throttle systems may also play a role.

There were reports from Japan on Friday that a recall affecting 270,000 Priuses was imminent. Toyota, which has recalled more than 9 million vehicles worldwide to address problems of sudden acceleration, declined to confirm such a recall.

Toyota, which has also been asked to study the braking problem by the Japanese government, said that it was cooperating with investigators and that it had implemented a "production change" last month to resolve the problem, which it says is in the anti-lock brake system.

Toyota is also investigating possible brake problems with its luxury Lexus hybrid, which uses the same brake system as the Prius. Toyota has not received any complaints about the Lexus HS250h, but the probe is to ensure safety, spokeswoman Ririko Takeuchi said.

A review of safety records indicates that the Prius is prone to a number of other safety problems that motorists complain have not been resolved.

The most persistent problem involves headlights. Since 2001, Prius owners have lodged more than 1,300 complaints about exterior lights shutting off without warning, most frequently the headlights.

According to complaints, the high-intensity discharge (HID) headlights, an option on the Prius, shut off without warning, sometimes in dangerous situations, leading to four crashes and at least one injury.

That compares with about 500 complaints of brake problems in the Prius for that period. Records show nearly 200 complaints linked to speed-control problems, mostly for unintended acceleration.

Prius owners also have complained of vehicles that shut off completely or stalled without warning, often while in motion, and of at least six incidents in which the hybrid's high-powered battery started a fire and destroyed the vehicle, among other problems.

Prius owners and experts suspect the complex electronics at the heart of the hybrid vehicle, a showcase for some of Toyota's most advanced technology.

"It's becoming alarming because it looks like there's a pattern here," said Melissa Harnett, co-counsel on two lawsuits against Toyota seeking class-action status on the headlight problem. "We believe this involves the entire electronic-control system."

The headlight complaint is particularly persistent in the 2006 to 2009 model years. Last April, NHTSA began an investigation. Counting reports to it and Toyota, the agency found 2,251 complaints from drivers and nearly 28,000 warranty repairs of the HID lighting system on the Prius.

The lawsuits claim there is an "inherent defect" in the Prius computer.

Toyota spokesman Brian Lyons disputed there was a problem with the vehicle's computer. The issue is "isolated to the bulb," he said, noting that many drivers used them in daylight, causing them to burn out more quickly.

In late December, the automaker began sending letters to 216,000 Prius owners offering to reimburse them for some or all of the costs of repairs to the headlight system.

In 2005, NHTSA investigated stalling in 2004 and 2005 models, in which consumers complained the engine shut down without warning.

The probe found most of the complaints were linked to an issue "with the program logic in the electronic control module (ECM) system," and Toyota indicated it would reprogram 75,000 vehicles to address the problem.

NHTSA's database includes 191 complaints of stalling in the 2004 and 2005 model-year Prius. Of those, 44 took place after the investigation concluded and Toyota began its safety campaign. In addition, there are more than 100 complaints of stalling in other model years of the Prius.

Material from The Associated Press is included in this report.