board and cooling fan starts running l went to citroen dealer get checked they changed the temp.sensor and programmed the computer system and after driving 5 miles the same msg came on.i changed the cooling switch too.but still have same problem coolant is fine.it cost me very exp. so far .can anybody help me please?

It sounds as if you have a fault in the circuit that is either damaging the temp sensor, a bad connector, ground fault, or wiring harness.. take it to a reputable auto electric place.

check the water level first.

l would agree with Jonny B on this one. The coolant temp sensor on modern Citroens r very fault prone, we change them regularly for the faults u have. Either have an auto electrician or ain dealer have another look & have them check the wiring between the sensor & engine ecu, a broken wire would cause the same fault. Also make sure u r changing the correct sensor as a car of this age may have a green sensor on top of the thermostat housing & another one (blue) under the housing screwed into the cylinder head. The one u want is the green one. If the dealer changed the sensor & it turns out to be a wiring fault try & negotiate with them... if the job was mis-diagnosed u may get ur money back.