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Hello hopefully someone here can guide me the right way! I have a 2005 jeep wrangler 4.0 manual transmission iv owned it for about 8 months now. I'm currently diagnosing p0153 for slow response from sensor bank 2/1. I replaced the sensor a few weeks ago since I thought that would fix the problem. I checked the code and freeze frame data and found that my fuel trims when the code was set off were all okay which is wierd cause usually a bad sensor/circuit would cause bad fuel trims right? Iv been watching the fuel trims and live data for weeks and the trims for bank 1 & 2 are perfect even with the check engine light on.
I finally decided to start diagnosing. Mitchell pro demand says I should see reference voltage from harness side when the sensor disconnected of 4.5v to 5v. I found 4.2v volts on both up stream sensors. Mitchell says to check all the wiring from the sensor to the pcm and grounds if all is okay it says replace the pcm. While checking the resistance in the wiring I found no faults and my ground to my sensor is okay. At this point I feel like I have a bad pcm.
I've deleted the code several times and after a few drive cycles I get the code back with no symptoms that indicate I have a fault anywhere. The Jeep literally runs perfect. Sadly I don't have a oscilloscope to see my waves from the sensors which maybe would be helpful but at this point that I checked all the wiring and replaced the sensor with a NTK one I feel like I'm ganna have pcm issue.
Something to note is that the pcm had already been replaced from the previous owner and I didn't notice till I actually looked at it and it looked fairly new and the tag says, the new pcm isn't even a year old! So idk were they bought it from, they could have probably have bought it from ebay and I don't know! Hopefully someone can put there input on this issue before I drop some money on a pcm thanks!
