I have a similar problem I wanted to share. Last February, I switched into h4 and noticed my vsc off flashing and trac lights on. The lights stay on when I switch back to h2 and only go away after I restart. They come back on as soon as I switch back to h4. Sometimes they stay off until I lock the center diff, which is weird. Not consistent. I get one error code of c1340. Was at the dealer for almost 3 months and they couldn't figure it out. They replaced my 4wd actuator switch and brake master cylinder and still the same problem. Thankfully the master tech didn't charge me because they couldn't solve the issue. 4hi and lo, and center diff still seem to work, but the lights still haunt me. Bugs me so bad. The only big change before all this was upgrading my front springs to 700lbs and wiring my ditch and chase lights. The wiring was suspect to me because I used factory switches. I upgraded to a switch pro and still the same problems. Frustrated and tired, I just chalked it up to Gremlins.

Here's my post about it back then.

HELP please! C1340 error, vsc off flashing and trac lights on