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Discussion Starter · #1 ·
Hey all, I’m new here but my truck has started acting funny in the winter months. When I first start it after sitting all night, my trans throws a p0700 code. Once the truck warms up a little code goes away and it’s fine all day. It also has no shifting issues at all. I’m trying to figure out if the tcm is bad or if I need to check a ground or what. Again, it only does this in winter. Spring summer and most of fall it never happens. Any help would be appreciated thanks!
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P0700 is just a generic code to illuminate the DIC. Your other codes you have pictured are the problems that need to be dealt with.
 

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Pull codes from TCM, as stated the P0700 is TCM telling ECM to put on check engine light. You should have more codes and be able to pull them with that scanner.
 

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Discussion Starter · #4 ·
I did pull them from the 700 code. It’s a high voltage to a pressure switch with the solenoids but once the truck is slightly warm there’s no issues for the day. It has no shifting issues and never has a problem after that. I’m just curious if my tcm is fried or I need to trace a ground.
 

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What are the actual 700 codes?
 

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I don't think your TCM is fried, I would check fluid level, ground, harness and connections to start.

If TCM was fried I think you'd have more codes and more symptoms.
 

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Discussion Starter · #10 ·
I don't think your TCM is fried, I would check fluid level, ground, harness and connections to start.

If TCM was fried I think you'd have more codes and more symptoms.
Ok I’ll start there. Truck has 181k on it and I’ve been hesitant on changing the fluid as to not disturb anything in there. Would changing the fluid be safe at this point?
 

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I would say yes, but do not put it on a flush machine as they don't work with Allisons. I don't recall the details, but do recall the HOOT method was recommended which you can find on the forum.
 

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Replace the fluid pressure switch.. It's on the bottom of the valve body..
Pick up a new switch and some fluid..
Pull the pan and you will see it.. (compare with new one).
It's easy to change.. A few bolts and a connector.

 
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Depending on the temps, the fluid may be so thick that it runs the pressure up till it warms up some. My 2011 did that the first winter I was here in AK till I put a pan heater on it to preheat the fluid.
 

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Discussion Starter · #16 ·
Depending on the temps, the fluid may be so thick that it runs the pressure up till it warms up some. My 2011 did that the first winter I was here in AK till I put a pan heater on it to preheat the fluid.
I live in PA so it may be possible that that’s the case. It only does this in the winter and I don’t know when the fluid was last changed so I’m going to start there when I get home from college for Christmas break. But once the fluid is over 65-70 degrees it’s totally fine. No hard up shifts or down shifts it’s smooth as butter. Also no limp mode either once it’s warmed up.
 
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