C3 SX diesel, bought December 2002.
About the middle of 2005, the engine warning light came on during a journey; I stopped and phoned the garage whence I bought the car.
I was told to wait a couple of minutes with the engine off; the system was being over-cautious. Good advice; that fixed it (and always has.)
However, it keeps happening, four times in one very unusual day during a journey of a little over 200 miles. Since mid December 2005, it's happened a total of nine times.
The garage seem puzzled; I was told to beware of driving too slow for the gear- go to gear n only at n*10 mph. They took details, saying that there had been other reports of this sort of problem. The exhaust recycling valve -have I got that right? -was mentioned after they connected it to their diagnostic kit..
Anybody else have a similar problem? The probability of my next car being a C3 was 90% a year ago; it's rather lower now.
-- Per ardua ad nauseam