Intermittent Check Engine Light, P0139 -
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Unread 04-05-2014, 10:09 AM   #1
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2000 WJ 
Join Date: Jul 2012
Location: Concord, MA
Posts: 113
Intermittent Check Engine Light, P0139

Hey all, I have a 2008 Jeep Patriot (2.4L engine) that intermittently has the check engine light on, always with the code P0139. The trouble code is for the Bank 1 Sensor 2 oxygen sensor or an exhaust leak so I went ahead and replaced the lower oxygen sensor (not the one in the engine bay, the one underneath the car to the right of the driveshaft) but the MIL still comes back on. Does that mean I would have an exhaust leak instead? I couldn’t find one for the life of me. What I did find though is a TSB that says this problem was found in Jeep Patriots and to fix it the PCM needs to be re-flashed. My question to you all is, do I have an exhaust leak or did the previous owner not get the PCM re-flashed when the TSB came out? Also, if the TSB came out in 2008, do I have to pay to have the re-flash done in 2014?


Last edited by ronj35; 04-05-2014 at 10:10 AM.. Reason: added link to TSB
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