I own a 2005 Nissan X-Trail 2.2 diesel Sport that was five weeks old when I bought it, now with 39,000 miles on the clock. A local garage has diagnosed a whining fault as indicative of my turbo about to fail. This will be my fourth turbo in the car and follows the replacement of my third one in May last year. Could you please suggest what the root cause of these failures might be? The engine electronics were ‘remapped’ in 2012 at a Nissan garage but this seems to have had no beneficial effect. Nissan accept no responsibility for the problem.