hi bobc5 This antipolution warning on a diesel refers to a small tank of very expensive Eoly fluid that is beside the fuel tank. Apparently it should be replenished at certain service intervals. The story goes that when your particulate filter fills up with soot this fluid plays a big part in removing the soot, something to do with tempretures. If you do not get this fluid refilled then you particulate filter will 'burn out' and need replacing. I know all about this as I have just had mine topped up £50 ish while it was in for it's 100,000 service. However, my warning message has not yet gone out - the agent said it takes a few miles, I will be contacting them again as I have done 600 miles and on its secound tank full. watch this space!!! ps - to make you feel beter - fords have this stuff aswell!!! 8 citroens from passing my test and still luv em!!!!! see this link for further info on what it does (oh and other stuff) www.psa-peugeot-citroen.com/en/psa_group/technological_files_b3.php