Casper Posted March 20, 2007 Report Share Posted March 20, 2007 P0328 Knock Sensor 1 Circuit High Input Bank 1 or 1 Sensor P0420 Catalyst Efficiency Below Threshold Bank 1 This is a guy at work's car. He's noticed a serious drop in fuel mileage and now these codes are popping up. I'm not sure what these are. Never dealt with knock sensors. The car only has like 80k on it, so I don't see the cat going bad already. Seems more logical that there's a problem with the knock sensor which is putting the computer into some type of safety fuel map. I'm probably way off, but that's my theory. I don't know shit about these cars. Any help is much appreciated. Quote Link to comment Share on other sites More sharing options...
SpaceGhost Posted March 20, 2007 Report Share Posted March 20, 2007 I think the car has been running rich because of the knock sensor going bad and now the cat is getting plugged, the cat is under waranty I believe, but the knock sensor is not. Quote Link to comment Share on other sites More sharing options...
verse Posted March 20, 2007 Report Share Posted March 20, 2007 I think the car has been running rich because of the knock sensor going bad and now the cat is getting plugged, the cat is under waranty I believe, but the knock sensor is not. Usually the cat's are only covered under warrenty for the first ~80k miles. Put yeah, at the least you have a bad convertor. Knock sensors can get set off unintentionally on some vehicles. Quote Link to comment Share on other sites More sharing options...
MeadEngineering Posted March 23, 2007 Report Share Posted March 23, 2007 FYI Subaru should have a 100K emissions warranty on it.The knock sensors fail on that model year all the time. Quote Link to comment Share on other sites More sharing options...
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