Sevice Engine Soon light & lack of power

[pitless]

I searched through the threads and did not see any that exactly matches my problem. When driving down the road the service engine soon light comes on and I lose power. The goes light goes off after a second or two. If I hold the accelerator down I continue with a power loss. Doesn't seem like the engine has died just less power. If I let off of the accelerator and press back down the truck runs fine again.

I had the truck checked for codes and there are no codes.

I have tried heavy acceleration and no problem.

Any suggestions? I bought a new fuel filter but have not put it in yet. The one in the truck is not too old so unless someone is pretty sure that maybe the problem I will just keep it in the truck.

Thanks for any help.

[jesilvas]

What are you using to check for codes? Because they are there.
It could be many things. Bad ICP, IPR, loose UVCH, IDM, CPS, and many, many other things.

[pitless]

I went to Autozone and had them check it. They said no codes. I don't have a reader. May need to take it in?

[jesilvas]

They can't read it.
A good mechanic shop should be able to read it. The dealer will charge a lot.
But don't let them tell you what they think it is, I'd just get the codes and let us know, especially if you can do your own work and just need ideas

[pitless]

Thanks for the offer of help but I need to leave town on Tues. and my wife needs the truck next weekend. I will need to take it to the dealer. Fortunately it is a small local dealership and usually doesn't take me to the cleaners like some others.

[jesilvas]

The question then is do they know what they're doing with diesels? Because I bet they will scan it, get some injector codes which can be phantom codes thrown by the cam pos sensor, and want to replace them if they don't know what they're doing.
As long as you have a good diesel shop who've worked on many of these, then you should be good.

[pitless]

The're fair. They do ok. But I am short of time. The one tech seems ok.

[kaya@bernhausen]

post the codes once you're informed of them. and any information you can get from the tech

[pitless]

The code, only one, P0603

Open KAPWR circuit

figured it was a loose connection or a broken wire. The PCM has been replaced with a Hypermax (any good?). He said it was loose, no brackets in the back. I wiggled it and pushed on it and it went in about 3/4"! I made a shim to take up the slack and it seem to be working fine.

When I get back I will check and see if I can tighten up the screw that is suppose to hold it in. I can not remove the PCM so the screw must be in part way.

Any comments or suggestions on if this should fix it or the Hypermax PCM is appreciated.

[jesilvas]

I bet there's a hypermax chip on the back of the PCM, where chips are installed. Probably a bad connection.
I'd get rid of the chip, if that's really what it is.
I've never heard of a HMax PCM though.