I had a code P0420. After speaking to multiple parties, I decided to replace my O2 downstream sensors (as my FlashPaq reader told me it was a downstream problem). I replace the passenger side, and the sma score came back. Now I've replaced the driver side, and I'm seeing code P0158 high-voltage something-or-other. How do I fix this? Where do I go from here? Do I need a new catalytic converter? I'm trying to fix this problem without taking it in and paying a bunch of money, but I don't know how to proceed. Thanks, Johnny
My car has 56000 miles.
My car has an automatic transmission.
Hi, thanks for writing in. I suspect your "upstream" sensor is the primary problem, and should be replaced. The downstream sensor you did replace is really measuring whether the catalytic converter (the main cat, not the pre-cat) did the job to clean things up. But the upstream O2 sensor does the heavy-lifting to tell engine management to lean things our, making the catalytic converters job easier. There is also a Jeep Customer Satisfaction program (CSC-10042886-7723) to re-program the software for the downstream O2 sensor to check more often under certain circumstances when the down stream sensor becomes slower to respond (as it ages). I recommend checking with Jeep for the Customer Satisfaction O2 Sensor reprogramming.
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