Rogue38 Posted March 16 Share Posted March 16 (edited) So, I have been getting the P0420 code for the last week or so on my 2007 Legacy Limited. Issues started with the P0171 code, for that I straightened the intake duct that was cocked and cleaned the MAF. That seemed to take care of that. Then the P0420 came up on the way home from work. Checked over the car with nothing obvious noted. I cleared the code and decided to see if it returned, set up and my ran my Actron live drive on the way to work and for the next few days. After several days I took the scanner off the car. Sure enough the code returned the following day. This was about 250-300 miles later, in the exact same spot on my commute. I viewed the freeze data and found the o211 mA at around 250.00. Once again, I cleared the code set up and my ran my Actron live drive on the way to work and for the next few days. The o211 mA is jumping around 0 to 250.00, when at idle or below around 50mph. On the open interstate 60 to 75 mph the o211 mA is 240 to 258. When slowing from 70 the reading drops to 0 to 5, then starts jumping up and down again. Fuel Trims seem to be normal as does other indications. Once again the code returned about two days and 170 miles later. I’ve done a bunch of searching on this issue, but most talk about voltages, which on my car seem to be normal. I could not find much on what the milliamps are supposed to be, except one article that leads me to believe it should be in the 1-5 mA range. I’m tempted to replace the front O2/AF sensor, but I am wondering if the high milliamps and jumping around is the sensor or something else. Car runs fine and 30 plus mpg. Here is a link to the video of the live drive showing the sensor indications: https://youtu.be/rE_UYyz9Ezw Any ideas? Edited March 16 by Rogue38 Link to comment Share on other sites More sharing options...
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