Please help with my engine light codes

[Danielgreig]

First off, I know it can be difficult to diagnose the issue online with just the codes. However I’m hoping to get some feedback on what to check. Now for the issue:

So my Tahoe was sitting for about a month due to a bad back injury I had. I finally got a chance to go and start it and it needed a jump. A buddy came by and jumped it for me and the engine light came on. I plugged in my scanner today and it shows the following codes. P0740, P0785, and P2761. All have to do with the transmission. Has anyone else had an issue like this? Does anyone know what I should check before taking it to a shop. I would rather fix myself if possible. Below are the pictures of the scanner. Any help is appreciated.


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[LionsGuy]

How does it ride? Have you driven it? Check the trans fluid? Any Leaks?

 

[Danielgreig]

How does it ride? Have you driven it? Check the trans fluid? Any Leaks?

I did drive it after the jump and it drove just fine but Only around my neighborhood. Got it to maybe 35mph tops and drove it for about 20 minutes. I haven’t yet check the transmission fluid. I will do that next once I get home.


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[Matthew Jeschke]

With all those open circuit faults i feel as though you lost a connection in your harness. Possible all those items are in one wire bundle?

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[Fless]

I'd be taking a good look under the body to see if there is any rodent or other damage to wiring, especially near the tranny.

 

[Danielgreig]

With all those open circuit faults i feel as though you lost a connection in your harness. Possible all those items are in one wire bundle?

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I was also wondering if it could be something electrical due to the dead battery and then the jump start. I’m hoping it’s not a fried ecu or whatever controls the transmission. I’m not sure how I would check that.


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[Danielgreig]

I'd be taking a good look under the body to see if there is any rodent or other damage to wiring, especially near the tranny.

I’ll take a look at that as well.


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[Matthew Jeschke]

I was also wondering if it could be something electrical due to the dead battery and then the jump start. I’m hoping it’s not a fried ecu or whatever controls the transmission. I’m not sure how I would check that.


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I dont think would be a fried ecu. Likely just a bad connection. There is a harness going to transmission... or possible a bad ground.

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[Danielgreig]

I dont think would be a fried ecu. Likely just a bad connection. There is a harness going to transmission... or possible a bad ground.

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Interesting....possibly a bad ground going to the transmission? Is there a ground wire just for the transmission?


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[Danielgreig]

Thanks guys for all the replies so quickly with ideas for me to check into. I really appreciate it.


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