Hi all, Still got this one! Have now fitted new EGR valve as bench testing old one showed the feedback pot was intermittent at about 3/4 open (but why no code?). Vehicle drives ok-ish now but power is down and code 1815 comes up, listed on ACR as "Intake air temperature sensor, intermittent lack of air in inlet circuit" on the Texa it says "Air supply circuit". Fault code will not reset although light does not come on straight away, when it does there is practically no power at all. My problem is what does the code mean? Is it trying to say lack of air flow or what? Sorry, long post again.