Return to shop that changed the pcm, sounds like they may have created the problem. Was the pcm a reman or new part? Possibly new pcm is defective or there is a wire worn threw and intermittenly grounding itself. Obviously check all he connections, make sure they are tight. Possible a wire got disloged or not connected properly when pcm was exchanged. good luck
If it's an analog speedometer, first check the condition of the speedometer cable. It may need to be replaced.
May have replaced the wrong sensor or you have a bad wire in that curcuit. gm Jim
If the odometer stopped working and the speedometer and cruise control still work, you have a bad odometer. It is part of the speedometer assembly so the whole thing will have to be replaced.
Replace the dash cluster that's what it sounds like to me since your tachometer and speedometer both don't work
you can go to speedometer and out of speedometer
Nothing
NO
Had same problem with mine. Also abs,tcs and e-brake light would come on when speedometer stopped working. Turned out alternator was putting out 16v. Replaced alternator and battery. Solved problem. Replaced both speed sensors first did not help. Good luck
If both the speedometer and odometer stopped working it is probably the speed sensor in the transmission gone bad. If only the speedometer quit you may have to replace the dash cluster with a reconditioned unit.
Broken speedometer cable?
check the fuse, the speedometer does not run off of a fuse
In my personal experience the speedometer stopped working because the mechanical drive cable broke.