not sure if its the same setup as xsara 2.0 hdi to test it, it has a 6 pin connector disconnect it and probe the pin-outs cable side with a multimeter, 2 and earth ignition on engine off should read 11 - 12 volts, component connected engine idling , probe 5 & 6 reading should be 2 volts, 5 & 6 engine idling - accelerate briefly voltage should be 4.4 you can spray the MAF element with carb/break cleaner but do not touch it the pressure of the spry is enough to clear and dirt/dust build up