2008 Dodge Ram 1500 Quad Cab SXT 4.7L Questions

[vinray89]

So I just recently acquired a 2008 Dodge Ram quad cab SXT with the 4.7L semi-hemi engine, meaning it has 2 spark plugs per cylinder for a total of 16 plugs. I have a couple of questions. First, when I turn off the ignition in the truck, the engine continues to run for a few seconds afterwards, is that normal? Second, are these trucks prone to the same exhaust manifold leak issues as on previous generations and models with the 4.7L engine? I had a 2003 Dakota with the 4.7, not the semi-hemi though, and it had the exhaust manifold bolts issue. I don't know, if my 2008 Ram with the semi-hemi is supposed to be louder or not? It's not extremely loud, but it sounds like it has an exhaust leak ahead of the muffler somewhere. Just wondering if there is anything else I need to look out for, as my truck has 245,000 miles on it. Thanks.

 

[vinray89]

So after running a basic code scan on my truck, I got the codes shown in the attached photo, most of which seem to pertain to the catalytic converter. I assume from the louder than normal exhaust, that it could possibly be missing, but I will have to get someone to look under there for me because I am physically unable to do it myself. I also got a code P0633, which means for Dodge vehicles that the SKIM (Sentry Key Immobilizer Module) secret key is not stored in the PCM (Powertrain Control Module). The SKIM system is a security feature that prevents unauthorized starting of the vehicle by using a key with a unique code that must match the code programmed into the PCM. When the PCM does not have the correct key information stored, it will trigger the P0633 code. So I am going to assume that this may have been what made the previous owner suspect that the PCM was faulty. I also assume that since I was able to start and drive the car, that the PCM may NOT be faulty at all, but the issue could be related to the SKIM module. Am I on the wrong track with this line of thinking? Is it going to be a HUGE pain to correct it? Somebody please help me out. Thanks.