Kyle Larson, the 21-year-old who won NASCAR's second-level Nationwide Series race on Saturday in Fontana, finished second.
"What an awesome race this race track produced for two days in a row," Busch said of the two-mile Fontana oval.
Busch drives the No. 18 Toyota and it was Toyota's first Sprint Cup Series victory of the season. Busch also became the fifth different winner in five races this year.
Busch's older brother Kurt finished third,
The race was marked by tire problems for several drivers, most notably reigning Cup champion
Johnson, who has won a record five times at Auto Club Speedway, was leading again with only seven laps left in the 200-lap race when one of the left-side tires blew out on his No. 48 Chevrolet.
Bowyer finished 16th, Johnson was 24th and Ambrose 30th.