Dads got an LMM 08', he called me and said I can barely get over 25mph and the engine reduce power light or whatever came on is that regen mode, I said well I think so but not sure, the light will not go off and not about 20mph, He's got approx 30k on it is this regen or a actual problem and he should disconnect banks and take to dealer?

Thanks let me know as soon as possible

Did he get a message saying "clean exhaust filter" ? If he did then the DPF filled up with soot... Is he getting any trouble codes? If he has the PDA it should read the codes... if he got the clean exhaust filter message he should disconnect the banks and take it to a dealer and they can to a manual regen to clear the DPF... this isn't the "best" way to fix the problem but I know it should work... if it's really bad they may have to replace it...

Now if it's throwing a DTC then I could be totally wrong about the DPF :D Check it out...

He is wondering if the maybe the fuel gelled because its minus 10 here in ohio,. But he yanked the pda banks power setup on there and the dealer came and towed it off.

He is wondering if the maybe the fuel gelled because its minus 10 here in ohio,. But he yanked the pda banks power setup on there and the dealer came and towed it off.

The reduced power light is coming on due to the cold. There seems to be a problem with these trucks at very cold temps (-10 is pretty darn cold). Check the air filter and MAF sensor and see if there's ice on it.