I have a 1997 Chevy Cheyenne K2500 4X4 5spd manual Ext cab 8ft bed with a 6.5l detroit diesel w/190k miles. I bought it 5-6 months ago. When I bought it, its check engine light was on. I ran diagnostics and got the codes P0236 and P0236pd. They're both the same codes. I looked up the problem and it was boost issues. I went down the line replacing sensors and switches. I replaced the boost sensor located on top of the intake manifold first. Then I replaced the wastegate solenoid. Then I replaced the wastegate actuator. At this point it was still throwing the code p0236. So, I checked the vacuum lines and the turbo itself. I ended up rebuilding the turbo. It didnt need to be rebuilt but I did it anyway. I ended up having to replace and relocate the pmd/fsd module and the code turned off. I relocated it inside the cab of the truck. Now, a week later, its throwing the code p0236 and p0236pd again. I was told by a mechanic out my way who calls himself Dr. Diesel that it was probably my catalytic converter all clogged up. So in my frustration I cut off the catalytic converter off and ran straight pipe from the head pipe to the muffler. And guess what? It still throws the same codes. WTF else can be causing this?