Hey Uguys& Gals, cruising bout 70 , went to limp mode, pushed it up hill and shut down, no overheat, no smoke , changed fuel filter 50 miles before limp, will not reset with key reset and unhooked both batteries, still no reset, tranny fluid good, sooty oil, very black, levels ok, replaced fuel filter, still no start, cranking good, no start, no codes with neighbors code reader, guess I'll buy one, any recommendations? Got Aug3 appt with Duramax guru, hopin to get miracle advise before appointment , first time I've used AAA in 30 years, got her home though, kinda reluctant to dig too deep, just checking the easy stuff.
LLY limp mode, engine light, complete shutdown
- Thread starter MikMax
- Start date
If there is an engine light (DTC) then there are stored codes. This will tell what is causing the issue. P700 codes, stuck in one gear but will rev past 2000 rpms and its a tranny limp. Fuel limp and will still shift but won't rev past 2k. LLY's also have harness issues, codes will be something like p0202/0207 and the truck will barely move and sound like it's only running on 4 cylinders. May give you a base line but really need to read the codes and hear the details of what happened. Even with the above codes, the truck should start.
No start? Sounds like a possible fuel limp. Definitely get the codes read and post your findings , then we can help diagnosis... Maybe the fprv opened and is stuck?? Kinda fairly common on lly's, IF it is the fprv it is a pretty cheap and easy fix. Can you get fuel to come out the bleeder on the filter head? Does the primer firm up nice after a few pumps after you close the bleeder? Do you have a way to monitor rail pressure?
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Probably should check out the fuel filter real well, may not be sealed well or possibly a junk filter. If I just changed the filter, that would be the first thing to look at
OK, thanx much for all replies, you helped a lot and I'll do some suggestions with filter, my first thought was filter cuz I just changed about 50 miles before, gotta buy code reader, any preference there? No use being brain dead bout this, I BE BACK! :thumb:
I'm having issues with my 01 GMC 2500HD duramax with built Allison transmission 6.6 lb7 So it runs an drives some days an them other days it won't an it will shift an go into limp mode an stay stuck in gear when it does this it throws codes for electrical solenoids an pressure control switch I've done a trans flush changed both external an internal trans filters an also the TCM 2Xs also don't know if it has anything to do with what's going on but my cluster goes out an my security light comes on an key won't stop singing even with the door shut any suggestions would b very much appreciated
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Best bet is to have the dealer scan it or find someone nearby with some EFI Live software. Many of the cheap scanners you'd buy at the auto parts store don't go deep enough.
