Carl Pettersson, another Swede, turned in a 68 to tie for third place at 4-under 140 with Jose Maria Olazabal, the 1994 and '99 Masters champion, and Vijay Singh, the winner at Augusta in 2000.
Four shots out of the lead at the start of the day, Sandelin charged into contention with a front-nine 31 that featured four birdies and an eagle at the par-5 6th. He added two more birdies to start the inward side but dropped shots with bogeys at the 12th and 16th.
Sandelin's birdie at the closing par-3 was inches from being an ace that would have earned him a new car, courtesy of the tournament sponsor.
'When I saw the ball in the air I said, 'Yes, come to me,'' said Sandelin. 'I was so close to my car.'
Sandelin, a four-time winner on the European Tour, captured his last two titles in 1999, the year he made his first Ryder Cup appearance. He is looking to make a good start to the new season after posting just two top-10 finishes in 2001.
'It feels great to be leading because this is the first tournament for the 2002 Volvo Order of Merit,' he said. 'I've always been confident because I know when I play well I can beat anyone. I just have to be more consistent and I've been working on that so we'll see what happens.'
Jimenez, whose last two wins came in 1999, as well, carded a bogey-free 69 made up of birdies on the first, second and 14th holes.
Singh, who recorded back-to-back victories in Asia earlier this year at the Carlsburg Malaysian Open and the Caltex Singapore Masters, shot 69, while Olazabal, the 2001 French Open winner, had his second straight 2-under 70.
Stephen Dodd (69), Thomas Levet (70), Stephen Scahill (71) and Jamie Spence (72) finished together in sixth place at minus-three.
Nick Faldo was five shots off the pace after a 70.
Sebastien Delagrange, who opened with a 68 for the first-round lead, ballooned to a 77 Friday and fell into a tie for 26th at plus-one. His birdieless round included a bogey and a pair of double-bogeys.
A total of 80 players survived the 36-hole cut, which fell at 5-over 149.
Full-Field Scores from the BMW Asian Open