08 lmm thats stumping me out!

[ecc_33]

So I have tuned 6 2008 lmm's. They have all been running fine until one of them came to me a week ago and said its getting a power derate message on the dash. I ran the codes today and got a P0402 exhaust gas recirculation flow excssive. I have that p0402 blocked via efi live set on not reported no mil. Why would it all of a sudden start throwing this code if all the Egr and dpf stuff has been deleted and been fine for 1 1/2 years? It does have a AFE cold air intake and the boots are really dry rotted. I told him to pull all the cai off and check for cracks and make sure the boots aren't ripped internally. Anyone else run into this problem?

 

[clrussell]

Are the egr blocked with a plate? If not unplug the egr valve..

 

[TheBac]

I shouldn't ask , but you have searched it, right? The threads I went back and read all pointed to a leak in the intake tract. You might be right about the dryrotted pieces. Worth a try.

 

[RENODMAX]

Let me look in my tunes I experienced a similar deal. My friend had an 08 that ran a tune for 2 years and when loaded into his new 08 it threw a CEL. I had to ask Josh H but he helped me sort it out.

 

[ecc_33]

I shouldn't ask , but you have searched it, right? The threads I went back and read all pointed to a leak in the intake tract. You might be right about the dryrotted pieces. Worth a try.

Yea Tom, Searched here and on diesel place. No the EGR isn't blocked. Yes, The egr motor is still plugged in. Thanks guys. I still don't understand why it didn't throw this code from the get go when all of the egr dpf stuff is turned off or set to no mill not reported?

 

[onebaddmaxxx]

can be a few things but I'm with tom. a leak in the boost system. Even seen the beginning of a MAF sensor going bad cause it.

 

[03_DMAX]

Put a blocker plate in it.

 

[clrussell]

Yea Tom, Searched here and on diesel place. No the EGR isn't blocked. Yes, The egr motor is still plugged in. Thanks guys. I still don't understand why it didn't throw this code from the get go when all of the egr dpf stuff is turned off or set to no mill not reported?

Unplug it and see what happens. Or blocker plate it would be best.. It will still try to open the valve even if it is turned off..

Had it happen a few times with no blocker plate

 

[onebaddmaxxx]

Its actually more coming to push the valve open . if you have a boost gauge and just have egr disabled on a truck, you can see after you hit over 20psi, it will spike then fluctuate as the valve is pushed open

 

[ecc_33]

unplugging the motor throws the same code. I suppose I'll tell the owner to buy a blocker plate. Its hard for him to understand he needs it now when it was fine for a year and a half.

 

[ecc_33]

egr blocker plate fixed it. Thanks for everyones help:hug: