Hello Folks,

I have a '99 ML430 that is displaying the 'Check Engine' light. I took it to a local motorsport shop and had the codes read, po170 and po173. I was told it means a bad air mass sensor. I bought my vehicle from CarMax and the MaxCare extended warrantee gave my local dealer such a run around that they suggested taking it to CarMax for repair. CarMax is telling me that those codes indicate a bad fuel pressure regulator. After searching the forums, the major of what I read would indicate a bad air mass sensor. What are the chances that CarMax is correct in that it's a faulty fuel pressure regulator? Anyone ever heard of this? Thanks for your help. -Norm