just coming home and the check engine light came on. now the truck won't go over 2000 rmp's. tranny guage showed about 200 deg and dropped quickly going down hill. not sure if that matters, i've just never noticed that before. all other temps and pressures seem good. does anyone know how to pull codes on an '01 duramax?

Did it start up and run normally after you shut it down? If so, you might have set the P1093 code for a restriction on the suction side of the fuel injection pump. When did you last change your fuel filter? To read the codes, try a dealer, Pep Boys or similiar - it requires a real code reader to do so.

yeah it did run good after i shut it down. check engine light still stayed on. i replaced the fuel filter about 5000 miles ago. i just replaced the air filter and the light went off and runs good.?????

hmmm. You should try and get some kind of code reader so you will know for sure what the codes are. Was the air filter clogged in anyway? was there any snow or slush in the airbox?

the air filter was pretty dirty. no snow or slush here. 70 deg and sunny. i'm taking it to the dealer tomorrow for new tailgate cables. i'll have them pull the code.

Could have been a tranny code since the temp got 200deg or hotter. I beleive the Allison will go into "limp" mode due to excessive fluid temps. Maybe someone else can correct me if I am wrong.

200 degrees isn't excessive temps....let us know what the codes are.

I was just concerned that it might have been over 200deg. Hopefully it isn't anything serious.

i will post the info tomorrow. i am still a little concerned about the tranny temp moving up and down so rapidly. i wasn't hauling anything, however i did change the tranny fluid and filter this weekend so it's got me freaked out. and yes i used the right fluid, and it's at the correct level. i'm curious about the limp mode you spoke of since that is exactly what i would say the truck was doing. the dealer said maybe injectors or bad fuel? they've had 4 trucks this month w/ similar problems and used a fuel additive to fix it. i'll post tomorrow when i know more.

I have put my tranny temp into the red before - it flashed the warning, but didn't limp it. 200, while not desireable, is not uncommon.

well the code came up as dtc p0093, major fuel leak. however there was no fuel leak found. i'm assuming it was more likely a drop in fuel pressure. i haven't had a drop in fuel mileage or power so i don't know what to make of it. according to the daignostic paperwork if it clears in three starts, which it did, that the code has cleared. i put some diesel fuel additive in and will probably change the filter.? if any of you have any other suggestions, i'm open to them. thanks.

Injectors, or Sleeves?

Bill

For the heck of it, keep an eye on your oil level and smell (for diesel)

The P0093 usually set due to a restricted fuel filter causing low pressure during higher loads or due to high return rates on the injectors. If it sets the light again especially when hot or looses power I would suspect the injectors. Sometimes they only act up, or are worse when hot. High return rate translates to the injector leaks from the high pressure side to the return side back to the tank. No visual leak nor fuel in oil sometimes. Hope this helps.:D