2015 JKU HOT OIL and U0101 Code

Txhorns13

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Joined
Apr 12, 2020
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Location
Texas
About 2 months ago I replaced the ignition switch on my 2015 Rubicon Unlimited due to a delayed start. I can turn the key to the start position and nothing happens. If i wait half a second longer and then turn the key, it starts. Since the new switch did not work, I reinstalled the old one. I then started getting a check engine light and HOT OIL warning light and alarm. I have watched every youtube video on it and have found nothing useful. I can turn the key to the on position and the HOT OIL light and alarm will come on with the engine not running. What I have done (1) Checked the fuses and all are good. (2) Upgraded the battery cables and ground cables with Jeepcables.com 0 gauge cables. I checked all connections and then upon starting it I get the HOT OIL light and alarm still. When running an OBD scan I get the code U0101 lost communication with TCM. I have checked and cleaned connections to the TCM, and see nothing wrong. Has anyone experienced this? If so what fix did you have?

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Have you tried resetting the computer? Force the jeep to relearn what it has. It's a free, easy, first thing to try.

 
About 2 months ago I replaced the ignition switch on my 2015 Rubicon Unlimited due to a delayed start. I can turn the key to the start position and nothing happens. If i wait half a second longer and then turn the key, it starts. Since the new switch did not work, I reinstalled the old one. I then started getting a check engine light and HOT OIL warning light and alarm. I have watched every youtube video on it and have found nothing useful. I can turn the key to the on position and the HOT OIL light and alarm will come on with the engine not running. What I have done (1) Checked the fuses and all are good. (2) Upgraded the battery cables and ground cables with Jeepcables.com 0 gauge cables. I checked all connections and then upon starting it I get the HOT OIL light and alarm still. When running an OBD scan I get the code U0101 lost communication with TCM. I have checked and cleaned connections to the TCM, and see nothing wrong. Has anyone experienced this? If so what fix did you have?

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Hi, I'm having the exact same issue. I've done a lot of work on it and replaced a lot of parts and sensors and still having the issue. The temperature gauge also starts going up when I'm driving, it's almost like it's not circulating coolant through. I've already replaced the pump and many sensors. How did you resolve it?
 
I'm getting the similar issue, intermittently . Cold engine, put in key, turn to on, sometimes the dash lights up like a Christmas tree. Turn to crank, no dice. Take the key out and put in back in 2, 3, 4... times and eventually it cranks, no weird lights and drives normally. Took it to a local Jeep shop, they found the K5 relay had a leg that looked like it had gotten a little hot. Replaced it but no change in behavior. New battery, cables are good, etc...
Any body have the solution for this one?
 
Check the connector on the small wire on the starter, the terminal can get corroded or loose.
Thank you for the reply BLACKJKU!

Checked it out, looks pristine actually. Connector looked good, wires up to the heat wrap looked good to.
I even went so far as to pull the TIPM up and checked out everything underneath. No rodent damage or damaged wires that I could see.
Also gave the TIPM a big sniff, nothing of a burnt smell detected.
 
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