I have a 01 duramax with 121000 miles and the check engine light will come on for a couple hours or days and then goes off again and this will happen a lot. When this started i took it to the dealer and it was my mass air sensor(got that replaced). Then a few days later the light came back on and it was the same code. After that it stayed off for a few weeks then all of a sudden it came back on again and the crazy thing is every time im on the way to the dealer the light cuts off or it will be off when they turn my truck on when they go to check it. I know yall cant tell me whats wrong but has anybody else ever had this problem? The light just seems to come on and turn off when it pleases. Im not losing any fluids and the truck seems to drive normal. But its does seem every once in a while when i go from a complete stop it seems the truck is slugish to take off or it feels like its in a higher gear then normal...TIA

:help:

Adam

Ok don't tell me you coast down a very long hill when it sets the SES? You may not relieze thats when it happens it took me a couple times to figure out thats when it was coming on....

Mine started doing that about 2 weeks ago and then it went to the shop and it was setting 5 diffrent codes FPR, Injectors, and some cooler lines is what they are replacing at this point, should pick it up tomorrow so I will have the detail on what was fixed!

The service guy which has no credablity with me since he basically refused to check my valve lash (because they are hydraulic which they aren't thanks Midwest ;) ) when asked said the coasting down the hill would let the FPR surge fuel worst through the system and set the code.
It would go off usually after a start up the next day....

i hope i dont have to replace that much stuff. Any 1 else have any thoughts? TIA....

Found the problem....My mass air sensor wires where hanging down and pinned between the turbo pipeing and frame. So i guess it must have gotten to hot and sent codes back to the comp....Thanks anyways guys.....

I was wrong, i didnt find the problem. The light came back on again and so i took it up to the dealer. The mass air was replaced and so was the filter....Still didnt fix it....I have no idea what to do, its throwing the mass air sensor code and we already replaced everything....

:help:

Adam

whats the code number?

dont know exactly but its the "Mass air performance" code....

If the wires to the MAF sensor were pinched the coating may appear to be OK, but the wire inside could be broken and only making good contact intermintantly. Did the service Tech check any of the ciruit, or just start replacing parts?

They just replaced parts, ill have they check the circuit next...

My SES light comes on as well sometimes. It throws a code P89???? (Fuel Pressure Regulator), but then it goes away. It seem to only happen when the truck is cold and sits at idle for a few minutes. As I said, after a couple more starts throughout the day it will clear itself. I am perplexed!!!!! Truck runs fine.



2003 2500HD dmax/ally