Gains by Toyota- and Lexus-brand light trucks, as well as Lexus cars, propelled the auto maker to its best monthly U.S. sales volume in 3 ½ years.

The No.1 Japanese auto maker delivered 205,342 units in the U.S. in March, up 4.8% on a daily selling-rate basis, its best result since August 2009’s 225,088. Fleet sales accounted for 12.2% of the March total, Toyota says.

August 2009 was the month “Cash for Clunkers,” the U.S. government’s program to spur new-vehicle sales by getting older models off the road, reached its pinnacle, and the last best monthly result for many Asian auto makers.

Toyota’s DSR result of 7,605 units sold over 27 selling days in March was not as strong as May 2012’s 7,807 over 26 days, WardsAuto data shows.

Despite the auto maker’s promotion of the Camry midsize sedan last month with attractive financing and lease deals, the model again fell below year-ago. Non-hybrid Camry sales declined 7.4% and the Camry Hybrid slid 14.4%.

“The market is very competitive, but we have Camry right on plan, at about 101,000 units coming through the first quarter, so we feel really good about our position,” Bob Carter, senior vice president-auto operations for Toyota Motor Sales U.S.A. says in a conference call with the media today.

Toyota will continue to offer 0% financing on the Camry in most regions in April, with ’12 models having longer loan terms than ’13 models, he says.

Despite high gasoline prices, the Prius hybrid also was in the red in March for the second consecutive month. Deliveries of the original Prius liftback and Prius V wagon were down 21.6%, while the subcompact Prius C fell 14.8% and the Prius plug-in hybrid was off 9.2%.

Carter blames the Prius decline on falling gas prices throughout last month, as well as a strong year-ago. March 2012 was the launch month for both the Prius C and plug-in models.

The Corolla sedan and new Avalon large car were the only Toyota-brand cars to see positive results in March, up 15.9% and 67.4%, respectively, compared with like-2012. The new Avalon Hybrid added 1,616 units to Toyota Div.’s monthly tally.

Light trucks, from both Toyota and its Lexus luxury brand, were especially robust in March, which Carter credits to those buyers returning to market at a faster rate than car buyers. Sales of the Land Cruiser large SUV, Sienna minivan and Tacoma midsize pickup climbed more than 20% from year-ago.

However, the all-new for ’13 RAV4 cross/utility vehicle saw a second straight month of falling sales, down 2.4%. Not included are the 133 RAV4 EVs sold last month in California. Carter says the compact CUV continues to have the thinnest days’ supply of any Toyota on dealer lots, 20 days.

A 39.3% surge in Lexus RX 350 CUV deliveries pushed total Lexus light-truck sales into the black, despite declines in the GX and LX SUV lines.

Lexus ES, GS and LS cars spiked significantly from year-ago, with deliveries of the ES 350 surging 72.9% compared with prior-year and the new-for-’13 ES hybrid adding 1,561 units.

The new FR-S rear-wheel-drive sports car continued to prop up Scion sales in March with 1,828 units. But with all other Scion models suffering declines, the total result for the month was down 0.4%.

“I continue to believe the industry is being fueled by what we call the three C’s: cars, credit and confidence,” Carter says of what likely will be the best month for new-vehicle sales in the U.S. since May 2007.

Toyota last week raised its U.S. industry forecast to 15.3 million sales, from 14.7 million in January, predicting the auto maker will account for 2.2 million of that total when 2013 draws to a close.

cschweinsberg@wardsauto.com