Hi I have a c3 1.4 diesel 90bhp citroen, I am having a slight lack of power. have took it to the garage and was told it was the turbo however am having no excessive smoke and as said before its just a slight lack of power. Are there any sensors etc which could be causing this? the spanner sign comes up on the dash when the ignition is on which makes me think it may be a sensor. have checked all oil levels and are ok. any help with this would be much appreciated. Thanks Andy.