recently ive been getting codes 4-5 and 12-6. My D revs at 1000rpms,neutral and park are 700 rpms. When i floor it, the tranny does not downshift. I replaced TPS, TCM, i even replaced tranny with another used one cause i thinkk this problem messed up my previous tranny, i do not know what to do now but bring it to the dealer. Anyone had this problem before or knows anything can help me, i have a feeling there are shorts throughout the whole wiring harness..

 

You sure it's not 0504? 1206 is the TPS though. Did you adjust it properly when you insalled it?

 

yes, it is 5-4, i adjusted it perfectly with a voltmeter, i even swapped another throttle body with the tps stock settings and i still have this problem