Switching from bypass 00 to tunes

[cleatus12r]

Originally Posted by deadeye1287

Hello, hoping someone can let me know a definitive answer on this as there seem to be a couple conflicting reports on if this is normal on some other sites. Just installed my chip in my 02 F250. Currently running firmware 2.85.0.10 with all TNAA4S2 calibrations for my VDH4 PCM. If I start the truck up on the bypass setting, when I switch to my tunes, sometimes the truck will stall and die, sometimes just stall, and sometimes it will switch to the tunes fine. If I start up on any of my tunes, it switches between tunes without missing a beat, goes to bypass fine and goes back to any tunes from bypass fine. I also noticed if I put the truck in the high idle tune or whisper mode tune, then go directly to bypass, it stays in high idle or whisper mode accordingly. I'm assuming the latter is normal, but it seems odd that I sometimes stall when switching from bypass? I've noticed it seems to die more often if I switch immediately after the truck starts and the dash lights go out. Thanks!

Normal operation.

The Hydra will not switch to "00" bypass mode without a key cycle. This means a change to "00" needs to be made, wait for the blink, then turn off the ignition. The next power-up will be in bypass. The chip WILL switch from bypass to any of the loaded calibrations without a key cycle...it stalls/stumbles because the calibration on the PCM does not match the calibrations on the chip. This is normal and nothing to worry about - just don't make a habit out of switching between "00" and other calibrations while the vehicle is running. If you must do that switch WITHOUT the engine running turn off the ignition and restart.