I have owned my 2010 3.0TDi A6 S-Line Special Edition (auto) for just over a week. I love the car! Keep finding new toys and features on it.
My only concern is that I notice that the MPG readings shown by the car are considerably lower than the Urban 30.1 MPG quoted by Audi. I have done a full VCDS Scan and have no fault codes showing. My daily driving is mixed between dual carriageway and lanes. I appreciate I did not purchase a 3.0TDi Quattro for fuel economy alone but was hoping to see better results from the diesel than 20-21 MPG averages.
I scanned the car with an EOBD package and was surprised to see the B1S1 Sensor Equivalence Ratio reading was mostly sitting under 0.4. I know with petrol cars the equivalence ratio should be 1.00 and the Engine Management system fights to maintain the value at 1.00. Is this different for diesels? I logged a full drive and am getting some very strange readings for the equivalence ratio - sitting at around 0.4 then jumping to 1.99. The car has 68K miles on it and I am wondering if the lambda sensor is failing. I have attached a screenshot of my readings below:
My engine code is: CDY0 (engine introduced in 2009 I believe).
Should I try changing the lambda sensor?