P0542 DODGE RAM - need more details on the code

Question

I have this code on my 2006 2500 cummins and the check engine light or service engine light does not come on as described. But I know that the light works due to it coming on before I turn on the truck. The truck seems to drive and operate just fine, but I dont want to have to spend 200 dollars on a new part, instead of just fixing some wiring problems in the truck. Plus on top of that, I dont know to much on the 5.9l cummins, or diesel motors in fact.