QuestionMy 1998 Toyota Avalon (mfg date - 5/98) check engine light is on and I am told by the service rep that it is a malfunctioning VSV which he says measures the degree of opening of the EGR valve. I can't find a part number in order to find a source to buy one but the serviceman tells me that you can't buy it separately, unless my car is a California car, and it now comes only as an assembly ($262+) that includes the EGR valve (which he determined was functioning properly). I have found a unit part called a EGR valve position sensor($38), but am not sure it's the same as the VSV. The car runs fine, has 59,000 miles and still gets good mileage. As I understand it, my car may be emitting more pollutants than originally designed to do, but it doesn't seem to have affected its performance. Can I just replace the VSV or the EGR valve position sensor (if they are one and the same), or is the serviceman correct in that I have to spend a lot to fix this?
AnswerMaybe you are getting an incorrect explanation, the first sentence doesn't make sense, the VSV does NOT measure the degreee of the egr valve opening, the EGR position sensor on top of the EGR valve does.
The VSV controls when the EGR valve is turned on and off, that's all it does.
As far as I know the position sensor is replaceable by itself, I have replaced them many times as this seems to be a common problem, the same goes for the VSV, maybe the service rep is recommending to replace both because this is a common failure and they don't want you to have a problem with one or the other in the future by replacing only one of them, this would make sense to me, the only part I'm not sure about is that the position sensor is part of the egr valve on a non-california car, I just don't believe that is the case and the factory manual does not mention that there is a difference.
Finally, if I could have the diagnostic trouble codes(DTCs) that were retreived I may be able to help more.
