fiat chief takes steering wheel the chief executive of the fiat conglomerate has taken day-to-day control of its struggling car business in an effort to turn it around.  sergio marchionne has replaced herbert demel as chief executive of fiat auto  with mr demel leaving the company. mr marchionne becomes the fourth head of the business - which is expected to make a 800m euro ($1bn) loss in 2004 - in as many years. fiat underperformed the market in europe last year  seeing flat sales.  the car business has made an operating loss in five of the last six years and was forced to push back its break-even target from 2005 to 2006. the management changes are part of a wider shake-up of the business following fiat s resolution of its dispute with general motors. as part of a major restructuring  fiat is to integrate the maserati car company - currently owned by ferrari - within its own operations. ferrari  in which fiat owns a majority stake  could be separately floated on the stock market in either 2006 or 2007.  mr marchionne  who only joined the company last year  said fiat auto was now the  principal focus  of his attention.  i have made the decision to take on the post of chief executive of the auto unit to speed up the company s recovery   he said.  a profound cultural transformation is underway following a management reorganisation that has delivered a more agile and efficient structure   he added.  although mr marchionne does not have a background in the car industry  he has been playing an increasing role in the group s activities. last year  he said that a series of new models  launched as part of the group s recovery plan  had not boosted revenues as much as hoped. the car business  best known for its alfa romeo marque  is expected to make a loss of about 800m euros in 2004. sales are expected to fall in 2005  fiat said this week  as it exits unprofitable areas such as the rental car market. mr demel  a car industry veteran  took the helm in november 2003 after being recruited by former fiat chief executive giuseppe morchio. mr morchio made a bid last year to become chairman after the death of president umberto agnelli. however  this was rejected by the founding agnelli family and mr morchio subsequently resigned. earlier this week  fiat reached an agreement with gm to dissolve an alliance which could have obliged gm to buy the italian firm outright. gm will pay fiat $2bn as part of the settlement.