The rubber foot button, is the exhaust brake you use it when you are slowing down, it works better at high revs than at low, when you are slowing down just put your foot on it and you will hear it and feel it if your revs are high enough, ring iveco up and ask them about immobilisers give them your reg number and they will be able to check if it was fitted with one from new.`
james, May 2009