Ok Im askign about this for CRAZYCUTER4.8 so I dont know everyhting just what he told me to ask. He is trying to tune 05 Silverado but is having problems flashing. The truck doesnt have Onstar but he does have a aftermarket Pioneer HU and thats what crazy thinks the problem is. Ok when he tries flash the pcm via OBD2 port with the new tune he is getting low engine power alert and he is also getting connection failed trying to connect to the BCM(not pcm). Any info would be great. Secondly has anyone tried or known if it is posisble to flash the PCM using HPT but using the Speartech harness(LS1Edit harness) obviously with the PCM removed? Thanks for the help!

 

Make sure the battery is fully charged. Also check for blown pcm fuse. It should be the cig. lighter fuse.

 

Pull the radio fuses. I had the same problem with my 04 using a HPP3. The aftermarket radio did something to it. I just pulled all of my radio fuse under the hood. I received the same code as well as Low TPS voltage. So I started pulling fuses.

 

also it will tell you the computer vcm volatge look in the lower left hand corner of the flash window should be above 12

 

pull the radio fuse.