I recently bought a 2002 Chevy Silverado Z71 4wh and I can not read thru the OBD port with anything I have including Modus Edge, LS Droid or anything! I have a bench harness setup and I can read the PCM that way but not installed in truck. Ive checked all the fuses and been checking the wiring as I found some wires bypassed at the PCM which seem to be CKP, Knock and something else i dont remember now so I reconnected to see what happens and no apparent changes. I have some dash lights on such as ABS and Airbags so I need to be able to read to clear etc not to mention for state inspections