The website has information for approximately 15 million owners of the 20 models recalled for a potential ignition switch defect, GM said on Saturday.
Some of the models now on the expanded website are Chevrolet Malibu and Impala sedans and four Cadillac models.
GM said it also mailed about 1.9 million letters from Chief Executive Officer Mary Barra to owners of the initial set of 2.59 million owners, urging them to bring their cars in for repairs.
More than 1 million letters went to owners who had not responded by ordering parts via the website or from dealers, and another 875,000 went to owners who ordered parts but had not brought their cars to dealers for repairs, said GM spokesman Alan Adler.
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By the weekend, GM said it had repaired about 800,000 of the 2.59 million vehicles in the initial set of recalls.
Adler said GM did not plan to expand the recall information website to include every recall or all recalled vehicles, primarily because they do not fit into a larger category as do the vehicles recalled for ignition switch issues.
Adler said the updated website and the letters were an effort to get vehicles with defective ignition switches fixed.
He said, on average, 80 percent of owners of GM vehicles get them fixed within a year after a recall is announced, and 85 percent after two years.