I have a 2002 blazer with the 4 button 4wd buttons it drove fine cut engine off then when refired and drove it would not shift and it feels like it is stuck in 4lo and no lights are on at the 4wd switch and 4wd service light is on I scanned the ecm and found an o2 sensor and mass air flow is showing bad but it is not drivable due to trans isn't shifting and all any help would be greatly appreciated thank uou in advance

 

 

All fuses have been checked and are good

 

Check wiring harness between PCM and trans. It runs behind the engine and can be damaged if the tranny had been remove, engine movement etc. Bare wires etc. will play haveck with tranny and 4x4.
Been there

 

I do know the motor mounts are going bad so I will have to check that thanks

 

The service 4x4 codes need a bit better than a standard obd reader to access them , a good reader and a good service manual could help point you in the right direction.

 

Check CLSTR Fuse11 in I/P fuseblock and for power at transmission connector on pink wire.