i have a 86 iroc with a 350. custom chip....when i got the snap on scanner hooked up it will not read any codes....put in the vin and all that and when it says turn key to on or whatever it shuts off the scanner....my lighter plug doesnt work so i have to use the power cord to my battery...i took it to a local shop and it did the same thing....what could the problem be? some guy said somthing about a locked chip....i dont know anything about chips, help me out..thanks