When I turn the key, nothing happens?

2009 KIA SORENTO
160,000 MILES • 3.3L • 4WD • AUTOMATIC
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KOIOS1031
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2009 Kia Sorento 3.3l no start

2009 Kia Sorento 3.3l no start

Hello, I've had my Kia down for about a week. I feel like I've been over everything. When I turn the key, nothing happens. Not even the starter clicking over. I have a few codes popping up.

U0101 (or similar lost communication code): Lost Communication with Transmission Control Module (TCM).

P0057: HO2S Heater Control Circuit Low (Bank 2, Sensor 2).

P0462: Fuel Level Sensor "A" Circuit Low Input.

I had a mobile tech come out and diag it as a bad inhibitor switch. Okay. I replaced that. Which is in the transmission of this car, ugh. Just for funises, I replaced the ignition switch. Still nothing.

I can jump the car from the starter relay, but it won't really engage the cars power. Limp mode maybe? But the starter will engage if I jump it from the relay pins. The relay does click and I've traded it out for the P/W relay to test the relay.

All of that, and nothing. I can't afford to take it to a shop. My wife lost her job and I work Instacart. (She's since started another)

Any ideas? Starter? I've checked the fuses. Everything seems right. Nobody I know has a clue
Oct 17, 2026 at 5:29 PM
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STRAILER
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Does the engine crank over when you jump the relay. can you upload a video of the problem so I can see it? These codes should not make the engine not crank over or the engine not to start. Here are tow videos to help us see what is going on so I can help you fix it.

https://www.youtube.com/watch?v=lXLJbuAZ4CE

and for not cranking over (starter)

https://www.youtube.com/watch?v=6YRW8fyNudY&t

Oct 18, 2026 at 8:45 AM
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KOIOS1031
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The car is in a no crank/no start situation. Nothing at all happens when I turn the key. However, if I jump the relay and turn the key, she starts up with no problem. Starts, but doesn't want to move very well. I can put the car in gear, and she'll go but it's very underpowered and it's almost like it's in limp mode. I've replaced the inhibitor switch/range sensor switch and the ignition switch in advisement from other mechanics. The starter relay has been switched from the power windows and the windows worked just fine. I've checked the relay socket for loose connections and didn't see anything concerning.
Oct 18, 2026 at 8:57 AM
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STRAILER
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Okay, then this can be the U0101 code issue. I would go over all fuses under the hood and double check them first, here is a video to help you.

https://www.youtube.com/watch?v=G-xNK79Wa-w
Oct 18, 2026 at 9:15 AM
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KOIOS1031
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I've used a multimeter and checked as the fuses from the under the hood as well as the cabin. Everything checked out. There is a person from Reddit that said the starter is engaged from the TCM
Oct 18, 2026 at 9:27 AM
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STRAILER
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Yep they are correct, that is why I wanted you to check the fuses to the TCM, I would remove the electrical connector from the TCM to check for corrosion which is common. Here is the location of the TCM so you can check it out, disconnect the battery first.
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Oct 18, 2026 at 12:17 PM
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KOIOS1031
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Hi, I wonder if you're still available? I had follow up questions. Sorry, I Disappeared. My daughter received some terrible health news that we had to address
Nov 6, 2026 at 11:21 AM
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STRAILER
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I am sorry to hear that, I hope she gets better soon. Yes I am still here. Did you remove the electrical connector from the TCM to check for corrosion? Here are the fuses to the TCM, check all three. Please let me know
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Nov 7, 2026 at 11:08 AM
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KOIOS1031
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Thank you for the reply. I have checked the fuses and the connector on the TCM. Everything is in tip top order. I'm fully at a loss at this point. It doesn't help that I have 10 family members coming at me with 10 different diagnosis'. Dad think it has to be the starter, one thinks the ECU. Ugh. Family.
Nov 7, 2026 at 4:45 PM
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STRAILER
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You said if you jump the relay the engine starts correct? If so the starter is not the problem.
Nov 8, 2026 at 8:26 AM
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KOIOS1031
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Exactly what I thought. Thank you for that.
Nov 8, 2026 at 9:52 AM
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STRAILER
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It seems like the TCM is bad, I would try getting another one from ebay or by searching google. If the fuses are good and the TCM has a good ground. Also I must tell you if something outside of the TCM is shorted such as a shift solenoid, it can shut the TCM down and make it seems like it is bad. To test for this we need to do a pinout with a voltmeter. You can test the shift solenoids from the TCM electrical connector, the resistance should be between 3 and 9 OHMS. Please go over this guide.

https://2carpros.com/articles/how-to-use-a-voltmeter/

If you have a hard short to ground somewhere in the system you have found the problem. Here are the complete wiring diagrams for the TCM.
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Nov 9, 2026 at 8:06 AM
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