I replaced the encoder motor. It still isn't going into 4HI, I am thinking that I need to replace either the tccm or the axle switch. If I am not mistaken, the axle switch is open when in 2HI and closed when the front axle is engaged.
If the switch is bad, a jumper wire between the terminals on the plug will tell the tccm that the axle engaged properly. Is this correct?

 

What is the correct way to rest the tccm? I haven't reset it and that may be all that it needs.

 

I pulled the 4WD fuse and the tranny fuse and left them out for about an hour. I then cycled the key on and off 5 times waiting for the lights to stop flashing each time before turning it off each time. It still will not go into 4HI, but the 2HI light comes on and stays on like it should all the time now. It will go into 4LO and the 4LO light is the only one on when in low range. I know that the vacuum switch on top of the t case is working properly, the actuator is engaging the front axle when it is in 4LO.
What is the next step? TCCM? Front axle switch?
Please help!

 

Did you re-run the diagnostic test?

 

Still showing code 2. Do I need to disconnect the battery or unplug the connector at the TCCM?

 

Correct way for a tccm relearn is pull the tccm fuse under the dash, leave it out for 30 minutes

 

The 4WD fuse?

 

Pulling the fuse or battery will still perform a hard reset..just pulling the battery will also do a engine and transmission adaptation reset.

When I bought my Jimmy the 4x4 didn't work at all. When I would push either 4HI or 4LO it would just flash. After diagnosing I found the diaphragm split, the Xbox switch stuck open, encoder motor seized in 2HI position..this truck is only a winter beater so I wasn't going to dump cash into this thing.

I removed the encoder motor and made sure the this can shift and drive in all 3 positions..this checked out so I replaces the encoder motor with a junk yard unit I found for 75$.

For the tbox switch and diaphram...I blocked off the this switch to avoid any air leaks, for the diaphram, disconnected it from the cable..I then used a cable clamp to lock the from axle engaged. Took off the battery for a reset...now works great. I only do city driving so the truck doesn't go over 60kph, didn't see any change in fuel consumption..

 

I pulled the 4wd and tranny fuse last night, left them out for about and hour. Still wont go into 4hi and I still have a code 2.

 

This is my daily driver, 177,000 miles on it. Runs great. Getting new upper and lower ball joints, tires, and alignment this week. Already replaced the idler arm and I have put a lot of money into the engine. ( full tune up, fuel pump, new injector assembly) I am looking at about $1000 this week alone. Are there any definitive tests I can do to determine what the next step is to get my 4wd working properly?