Fiat Chrysler is recalling more than 566,000 trucks and SUVs in two recalls for malfunctioning fuel heaters that can cause fires and a software glitch can disable the electronic stability control.

The recalls bring the newly merged company’s total for the year to 6.4 million vehicles worldwide and 5.1 million in the U.S. as it continues to struggle with reliability problems. It was not immediately clear whether those totals were annual records.

On Tuesday, its longtime quality chief abruptly left after Fiat Chrysler performed poorly in Consumer Reports magazine’s annual reliability rankings.

The largest of two recalls announced Wednesday covers almost 382,000 Ram 2500 and 3500 pickups and Ram 4500 and 5500 chassis cabs from 2010 through 2014.

In trucks with 6.7-Liter Cummins diesel engines, corrosion on a fuel heater terminal could cause overheating, fuel leaks and fires. Chrysler is not aware of any fires or injuries. Owners could be warned by an odor of diesel fuel.

Customers will be notified by letters starting in December. Dealers will install upgraded terminals and fuel heater housings could be replaced.

The second recall covers more than 184,000 Jeep Grand Cherokee and Dodge Durango SUVs from 2014. A debris cover over a circuit board in the steering column control module can disrupt communications and disable the stability control. The problem was discovered when dealers started getting reports from customers that electronic stability control warning lights were coming on.

Fiat Chrysler says it knows of no crashes or injuries caused by the problem. Technicians will upgrade software to fix the SUVs, and customers will be notified in December.

Fiat Chrysler has issued 33 global recalls and 27 in the U.S. so far this year. Doug Betts, its longtime quality chief, left the company to pursue other options after Consumer Reports’ survey-based rankings this year showed four Fiat Chrysler brands at the bottom of its list. Dodge, Ram, Jeep and Fiat performed worst of 28 brands ranked by the magazine.

Company spokesman Eric Mayne said Fiat Chrysler’s recalls average fewer than 200,000 vehicles each, below the industry average of 301,000. That means the company is responding quickly to problems, he said, adding that eight of its 27 U.S. recalls were announced before the company received any consumer complaints.

Chrysler is not alone with a high number of recalls so far this year. Stericycle, a company that tracks recalls, says companies have called back more than 52 million vehicles so far this year, breaking a record set in 2004.

(AP)