6l80e transmission fluid pressure sensor/ switch circuit low

[apollo18]

hey guys! i have a 2007 truck with a 6l80e transmission. The truck has a 1-2 hard shift. and the 2-3 is slightly wonky.. 3-4, 4-5, and 5-6 are PERFECTLY SMOOTH. The tranny has stock tune on it so does the engine. Fluid and Filter was just swapped out with pan drop about 5 months ago. This problem has been going on for like 1-2 years and i never bothered to fix it since I dont drive the truck that much. This is also the 2nd transmission. It has about 200k km's on it, and was brand new from GM. Had it installed in 2011/2011.  Two weeks ago, I had a mechanic use a tech 2 to check it out. He reset the trans adapts and the problem went away for about 10 days. It shifted perfectly smooth every single shift. But now the problem is back. the 1-2 is hard, and the 2-3 is slightly hard. He wrote down the codes and was supposed to get back to me about how he was gonna fix it, but he never did and stopped replying now. The truck now went back to how it used to be. A diff mechanic I found used a MacTools Mac TaskPlus and got 4 TCM codes. The codes are:

P0872 Transmission Fluid Pressure Sensor / Switch C Circuit Low
P0877 Transmission Fluid Pressure Sensor / Switch D Circuit Low
P0842 Transmission Fluid Pressure Sensor / Switch A Circuit Low
P0989 Transmission Fluid Pressure Sensor / Switch E Circuit Low

these are the 4 codes. Im guessing this sensor/switch is bad and needs to be replaced?

anyone have any help/info?

thanks alot!!

[Jsdirt]

Usually with multiple codes it's a wiring issue. Check wiring connectors, and areas of heat & vibration. Since the trans was recently swapped, look around the tranny/block mating surface for any wires pinched in between.

 

"Circuit low" suggests a short to ground, open in the signal wire, or a PCM problem.

[Justin101714]

Get the pan off. Take a pencil with an eraser. Using the scan tool, you should be able to take the eraser and push on the switches, the information of the scan tool should change. Such as “on” or “off”. Make sure you have ground coming as well. If you have it all and the data looks good. Put a switch in it


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[apollo18]

thanks alot guys! 

[apollo18]

11 minutes ago, Justin101714 said:

Get the pan off. Take a pencil with an eraser. Using the scan tool, you should be able to take the eraser and push on the switches, the information of the scan tool should change. Such as “on” or “off”. Make sure you have ground coming as well. If you have it all and the data looks good. Put a switch in it


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could you elaborate more justin? im gonna try that thanks thanks

[Justin101714]

Let’s just say your pressure switch manifold looks like this. Remove the pan and remove this manifold. You need to find a way to ground this switch to the trans body. What I do it run an alligator clip to any piece of metal on the switch to any piece of metal internal to the trans case. With the electrical connector plugged in as well, you can take a pencil, eraser side and press those switches, the inside part of those circles, the data should change from on to off on each individual switch. Your pressure switch manifold may not look exactly like this one, but the circles should look the same.


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[apollo18]

ohh makes sense!! thanks alot! and that will tell me if its a connection problem or a switch problem?

[Jared’s Chevys]

Did you ever figure this out because I am having the exact same problem in my Yukon with exact same codes. However all my gears are good except 4-5 upshift it feels like you got rear ended. I had tech read it with snapon scam tool and had those same 4 codes