if your front acuator is getting vacumm when in 2hi then the vacumm switch on top of the transfer case is stuck open.its where all the vacumm lines go into near the top of the t-case. only like a 7 dallar part. 15 at the most. and i think there is a sensor on the front differential that tell the ecm if its engaged or not and if its engaged when not it 4hi or lo then it will spit out a error code and NOT shift into 4x4. so check that vacumm switch near the top of the tcase. and if that dont fix it then its definitely the ecoder motor. its not the tccm cause its doin its job. cause your hearing the clicking noise coming from it so it cant be it.

 

okey thanks for your good answers i will try replace the vacuum switch on top of the t-case then.

 

sorry for bumping an old thread.
just thought I was gonna post what I did to fix my 4wd problem incase anyone have similiar problems and want a quickfix.

Instead of trying more to fix my problem by replacing parts, I just pulled off the whole elecronic actuator, took off all the wires connected to it and now im just changing it into 4hi and low with a 15mm wrench, later this summer im planning to make a homemade shifter so I dont have to crawl under the car to change gears.

I dont like elecronics so im trying to get rid of as much as I can, my 4wd have never been more reliable