Electrical hiccups after extended battery disconnect


New Member
Sep 17, 2023
Baton Rouge, Louisiana
Good morning to all! I am new to this forum and a new Jeep owner as well. I recently purchased a 2012 Unlimited Sahara. I did my research beforehand and was aware of the valve train issues and leaky oil cooler on this model. I did not hear any valve train noise, but noticed a small oil leak from up top. So I decided before I really ride it, I would replace the oil cooler with an upgraded aluminum body, and replace valve cover gaskets, spark plugs, boots, and check the valve train while I was able to. I also had a code indicating a “catalyst below threshold” bank 2. I attempted to run a cleaner through it but no luck, so I decided to replace it. I did all this work in 2 days. When starting up after finishing, the AC compressor will come on but shut off at random times. I also have a “cooling fan open circuit” code. I triple checked all connections. Also, I did disconnect one of the harnesses from the ECM to make room to work. I also removed the battery tray while keeping the fuse box plugged in just draped over the fender. I have seen numerous ways to reset the ECM. Which is the correct way to reset? Any other suggestions please…. Thanks in advance