# Need some help with a 2003 Yukon Denali

**URL:** <https://forums.speedlife.net/t/need-some-help-with-a-2003-yukon-denali/157230>\
**Category:** NYSpeed Automotive\
**Created:** [June 29, 2010, 9:49pm UTC](https://forums.speedlife.net/t/need-some-help-with-a-2003-yukon-denali/157230 "2010-06-29T21:49:14Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![nytalonTSi](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/nytalontsi/32/5399_2.png) [@nytalonTSi](https://forums.speedlife.net/u/nytalonTSi)\
**Post date:** [June 29, 2010, 9:49pm UTC](https://forums.speedlife.net/t/need-some-help-with-a-2003-yukon-denali/157230/1 "2010-06-29T21:49:14Z")

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This is my mother’s SUV, 6.0 Vortec, 4L65-E trans has almost 88k miles on it. Truck was running fine till yesterday she told me the truck felt like it lost power.

So when I got out of work, as soon as I start up the truck it throws a CEL. I drive it and at one point there was a delay in the tranny shifting. Then later truck seems normal and safe to drive after a few hours my mother tells me the CEL wasn’t staying on anymore.

I scan for the codes I end up pulling P0740- Torque Converter Clutch Circuit Malfunction, P0785- 3-2 shift solenoid or what it seemed at one point 2-3 shift and P1860- Torque Converter Clutch PWM solenoid. So it’s all in the tranny.

I’m not familar with this electrical stuff, I plan on replacing the tranny fluid and filter maybe some debris or what not is causing this havoc.

I did some research and I came up with similar GM vehicles with same trans throwing the same codes and all problems pointed to a faulty **ignition switch**. The only problems my mom’s not having is a cluster issue. Anyone can maybe guide me or have had this problem?

Thanks.