Anytime I try to connect HP tuners into my truck, if I do not have my factory radio installed it will not communicate with my truck. I am not sure if different factory radios will also work, however with an aftermarket unit it was no good. The truck was originally tuned with AM/FM radio installed and since then if I try to tune with it either disconnected or a different aftermarket unit in its place HP tuners will not communicate. Anyone else had this issue?

 

try pulling the radio fuse while flashing.

 

The stock radio is connected to the class two data bus. Maybe unplugging the radio pulls the bus voltage too high or something. Try testing all the pins on your odb2 port for correct voltage with and without the stock radio. See if removing the stock radio screws something up.

 

I program a lot of trucks. Around 300 just last year. On 03-07 classic trucks, I only have problems with some aftermarket radios installed. Never a problem with the factory radio. And never a problem with any radio on 96-02 trucks. Seems some chime/data bus adapters work better than others. On the ones that are problems, I'd say 95% of the time pulling the radio and radio amp fuse will allow reading and writing. When that doesn't work I either use a bench harness or pull the radio and unplug it from the vehicle. Another thing I see more and more lately are aftermarket remote starts that tap into the purple data wire on the ALDL plug have to be disconnected to read and write to the pcm.

 

Thank you for all the replies. Next tuning session I'll try pulling the radio fuse just to see if that fixes the problem. I'm OK with the AM/FM unit that I have now. I will probably upgrade to a better factory unit, but it's going to be a minimal Soundsystem at best. I was really just curious if anyone else has had this particular issue. Back when I had a sub and aftermarket radio it was a little cumbersome however I could swap radio units in under five minutes so it wasn't a big deal.

 

Do you have any add-on modules? Like the one that interfaces with the steering wheel?

I had a similar problem until I rewired mine, removing the module. Been fine since.

 

Not anything I added. This was a govt truck before I owned it so I doubt there is