P0299 is a fault that sets when the difference between EP and commanded EP exceeds the limit for more than 30 seconds. It's caused by the following: Faulty EP sensor, VGT valve slow to respond, stuck VGT valve or a faulty PCM. EP being exhaust pressure. If your truck seems to be performing "OK" then it's probably from stuck turbo veins or a crapped up EBP sensor. It could also be caused by something your module is doing or commanding that the PCM doesn't like. Remove the module and see if the code returns. If the code doesn't return, use the module for a trotline weight and buy an SCT that won't trash your tranny.