NEW YORK (CNN/Money) - General Motors Corp. on Wednesday began offering its popular zero percent financing incentive on many of its 2004 vehicles, a move that has already heated the incentive battle among U.S. automakers.

CNNfn's Fred Katayama takes a closer look at September auto sales numbers. Play video (Real or Windows Media)

GM, along with Ford Motor Co. and Chrysler Group, previously offered zero percent on 2003 models in an effort to clear out inventory and make room for the new models. GM's move Wednesday offers zero percent financing for up to five years on virtually all its 2004 cars and for up to three years on most of its light trucks, such as pickups, sport/utility vehicles and minivans.

The GM (GM: Research, Estimates) offer also includes cash back for those not choosing financing, and offers interest rates between 1.9 and 3.9 percent for five-year financing packages on the light trucks. Most Cadillacs and the Chevy Corvette do not have the low-interest financing offers.

As expected, GM also extended the zero-interest financing offer on its remaining 2003 vehicles still in stock.

Ford (F: Research, Estimates) let dealers know that it will offer zero percent financing over 36 months on some select vehicles, including its best-selling cars such as the Focus and Taurus, but it did not offer 60-month zero percent financing on any vehicles. Ford spokesman Jim Cain said Ford will look at GM's offer and decide soon how to respond.

Related stories • Ford, Chrysler plan job cuts • New incentives for car buyers • Wait for incentives on '04 models • Cars: Decision 2004 • No incentives? No problem.

But Chrysler announced it will increase its incentives by up to $2,000 for those who choose cash-back options on 2003 models and $1,500 for 2004 model-year vehicles until January 2004. The automaker has zero percent financing for 36 months pretty much across the board, and offers 60-month zero percent financing on a handful of vehicles, including the Neon, Sebring, Concorde, Intrepid, 300M, Grand Cherokee and its minivans.

Chrysler, a unit of German automaker DaimlerChrysler (DCX: Research, Estimates), also added a bonus for customers who lease their vehicles; customers can terminate their lease and have up to five payments waived when they buy or lease a 2003 or 2004 vehicle.

"These innovative programs lay the groundwork in the marketplace for the Chrysler Group's upcoming product office," Gary Dilts, the senior vice president of sales, said in a press release.

YOUR E-MAIL ALERTS General Motors Corporation Auto Incentives Automakers or Create your own Manage alerts | What is this?

The Big Three automakers' sales and market share have declined, although sales are still at a historically strong level thanks at least in part to increased incentives.

The incentives have hurt profits, though. GM's earnings per share, excluding special items, are expected to fall by about half in the recently completed third quarter, while Ford is expected to post a loss and DaimlerChrysler is expected to show a drop in earnings due to an expected loss at the Chrysler unit.