Chevy/GMC Duramax 04.5-05 LLY Discussion of Chevy and GMC Trucks with LLY Duramax Turbo Diesel Engines

LLY limp mode?

Old 08-27-2016, 03:22 PM
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Default LLY limp mode?

Was driving in town yesterday and the cel came on then the truck sounded like it had a fuel knock and had zero power. tranny shifted perfectly fine and engine ran great before but then the tranny shifted hard, only revved to 2k, and had very little power. I let the truck cool off for a little and then it was fine. After a few minutes it happened again. Let cool off and then again. After each time it happened sooner and sooner. It got to the point where it wouldn't come out. I assume it's limp mode but i'm really not sure. I changed the fuel filter drove fine for a few miles then started acting up again. Really just looking for some opinions I'm new to duramaxes so I'm sure you guys know much more than me.
Old 10-02-2016, 07:06 PM
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Check the wiring harness to the tranny. There's a seal of sorts when it goes trans fluid will find its way into the wiring harness. It will saturate the connections.
Old 11-11-2016, 02:15 PM
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any codes?

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