Just a quick post to introduce myself. I've been a diesel owner for a few years now. Been a member here for six months or so. I've looked at various topics over the last few months to do some troubleshooting on my '05 GMC 2500HD Duramax LLY. I had a problem with my CD player and the dreaded "limp mode" on my truck. I took it in to the dealership yesterday to get the work done under warranty. They called back today to try to tell me the "limp mode" was caused by a clogged fuel filter. I said not so fast my friend. When I first had the problem, I put a new fuel filter on it, drove it about a hundred miles, and it did it again. I took the fuel filter off, cut it into with a chop saw, and it was clean as brand new. Put another one on it and drove it about 300 miles, same problem. No warning lights are coming on and the truck has as much power as the day I picked it up from the dealer when it had 1.5 miles on it. As soon as I get it out of the shop and see that it's fixed, I'll make another post with all the particulars on it. Hopefully it will be helpful to some of ya'll with the same problems.

Do you have any mods the truck. Sounds like a fuel pressure relief valve to me..

I don't have any mods on the truck whatsoever. Still have the original exhaust on it. The first few times it did it, I was pulling a dual tandem 25' gooseneck with about 7500lbs. on it. The next day, it did it with the trailer empty. About a week later, it did it on the interstate while passing someone going up a small hill with no trailer. Never an SES light or anything. I went to Houston TX last week pulling an empty trailer and came back loaded with about 6500lbs. About a 1700mi round trip. No problems at all. Two weeks ago, I made a 150mi. trip with 15000lbs. of telephone poles on the trailer and damn near got a speeding ticket. The damn thing was a pulling machine. There's no rhyme or reason to whats going on. I appreciate any help you can offer.

Even if the light does not come on there may still be a code set. If you can I would get it scanned.

where ya at if your close before i send in my predator i could meet ya some where if your close and scan ya truck:) Even if the light does not come on there may still be a code set. If you can I would get it scanned.

Just a quick post to introduce myself. I've been a diesel owner for a few years now. Been a member here for six months or so. I've looked at various topics over the last few months to do some troubleshooting on my '05 GMC 2500HD Duramax LLY. I had a problem with my CD player and the dreaded "limp mode" on my truck. I took it in to the dealership yesterday to get the work done under warranty. They called back today to try to tell me the "limp mode" was caused by a clogged fuel filter. I said not so fast my friend. When I first had the problem, I put a new fuel filter on it, drove it about a hundred miles, and it did it again. I took the fuel filter off, cut it into with a chop saw, and it was clean as brand new. Put another one on it and drove it about 300 miles, same problem. No warning lights are coming on and the truck has as much power as the day I picked it up from the dealer when it had 1.5 miles on it. As soon as I get it out of the shop and see that it's fixed, I'll make another post with all the particulars on it. Hopefully it will be helpful to some of ya'll with the same problems.

Are you doing a tranny limp or engine limp?

I appreciate the offer Mr. BaadBoy, but it's at the dealership right now. If it wasn't still under warranty, I would take you up on that offer. I'm in Hartsville about 45 min. from Springfield. I usually get my work done at Cunningham's up in your neck of the woods. I took it to Lebanon this time cause it's closer for me. If I have some more problems with it, I may call on you for some advice if thats cool. Thanks alot partner.

I don't know for sure. I would guess an engine limp since I don't have any mods on the truck and it does it sometimes when I'm not pulling anything.

Moved to the lly forum, sounds like a p1093 to me also....

Probably the dreaded PRV valve, shim it or add a lift pump. Member of the none P1093 code since I installed the lift pump 15K ago.

Limp Mode + no cel = 1093 (FPRV needs shimming) somewhere around 99.9999999% of the time. :)