Braking news on Prius

The Toyota Prius is the poster child for the green movement's vision of personal transport for the future, but media speculation is rampant that the hybrid-drive small car will be the subject of a recall.

As the Carsales Network reported yesterday, Toyota Australia (TMCA) has issued a statement that the company will rely on its "well established process" to evaluate the merit of the customer feedback. It will then settle on the appropriate course of action, tending the needs of Prius owners concerned about the car's brake-pedal feel.

"There's no decision to issue a recall at this time," Mike Breen, TMCA's Manager Public Relations told the Carsales Network today.

"The situation... is it's a brake pedal feel issue, not a brake performance issue. So, with the electric and the hydraulic braking system in the Prius... there is a slightly different feel in the pedal, driving the vehicle with regenerative braking -- so it's that pedal feel that customers have reported concerns with, not the actual performance of the braking system."

"There's a perceived delay, but in fact the brake system is still working to its desired performance, so there's no... increase in braking distance, the brakes are still working, it's the feel through the pedal that gives the perception. That's why people are reporting the issue."

Breen didn't expect TMCA would issue a recall for the Prius, despite the company receiving "a small number" of reports from Australian owners.

"There's still information coming from Japan at this stage, but from the inspections Toyota has made, there's no decision to make a recall.

When it was put to him that the brake pedal feel for the Prius would be less of a problem in Australia, since our climate is milder than that of Japan and North America, Breen agreed.

"That's right. It's all down to the driving conditions: icy roads, potholed roads, things like that."

Asked what remedies TMCA would administer for existing owners unhappy with the brake pedal feel, Breen replied that the most important point was for those owners to take their cars to their nearest Toyota dealer.

"The dealer will send a report to our Technical Services people and they'll investigate it and respond," he said. "The TSO people, our Technical Services Operations, they have field reps and if a dealer rings and says 'I've got a customer here with an issue' with their brake pedal or their tail light or whatever, the Technical Services rep goes visits the dealer, meets the customer, looks at the car... that sort of thing happens."

So by visiting the dealer first, the Prius owner is taking the first step to address the concern. Breen also explicitly stated that the Prius situation would have no bearing on the locally-produced Camry Hybrid, which is due to be released officially early next week.

The story so far has been carefully monitored by Japanese media outlet, Nikkei.com. According to its coverage, Prius owners both in the US and Japan are reporting what seems like a pause in the car's braking when its ABS (anti-lock braking system) activates in slippery or bumpy conditions. It forces the car's brake system control software to change mode from purely regenerative braking power to conventional hydraulic braking. The driver notes the extra processing time and registers that as a hesitation in the car's deceleration during the change in braking mode.

Regenerative braking comprises an electric generator that converts kinetic energy to electric energy for storage in a battery. ABS, which ensures that the car won't lose braking grip or the ability to steer around objects in an emergency, only operates in conjunction with the hydraulic braking system.

Writers for the Nikkei quoted Hiroyuki Yokoyama, Toyota's general manager of the Customer Quality Engineering Division, to support the claim that the "pause" was due to software switching the braking system between the two modes.

"When driving on an icy road, the shift from the electronic brake to the hydraulic brake sometimes takes longer than usual," Yokoyama explained.

"It's a matter of 'driving feel'," he said. "Regrettably, we underestimated what customers would expect from the vehicle."

He confirmed for the journalists that last month Toyota reprogrammed this software for cars being built, but will only download the new software to customers' cars on request from the owners. The company has not broadly disclosed the change of software in the production process, believing the complaints reflected the owners' lack of experience with hybrid vehicle braking systems, rather than a safety issue per se.

"At first, we thought the complaints were due to users' unfamiliarity with the hybrid's brakes," Yokoyama explained. "But as it got colder in December, the number of complaints increased. This was when we began to consider a remedy, which we carried out in January."

Toyota first looked into the issue after the company and Japan's Ministry of Transportation began receiving complaints, not long after the car went on sale in the Japanese domestic market. That was May 2009, two months prior to the car going on sale in Australia. The Prius was hitting local roads in the very depth of winter and right through spring, which is the rainy season in some states.

Nikkei reports that the National Highway Traffic Safety Administration in the US has opened an investigation into the Prius. The safety legislator is already in receipt of 124 incidents involving the Prius and its braking system, including four crashes.

Read the latest Carsales Network news and reviews on your mobile, iPhone or PDA at www.carsales.mobi