2000 suburban transfer switching problem

I am having trouble finding the root cause of my 4wd issue. I changed the dash switch, the exterior case motor (actuator), and still no fix. all dash lights blink and switch returns to 2whi or auto mode. does not engage 4wd hi or low. codes post to CO383 and CO323- locked circuit low ? I don't know what these mean. does anyone know where to point me? thanks for advice.

What transfer case?
Mileage and ever been serviced?
Code 323 is lockup circuit problem.
I do not see code 383 listed for a 00 sub transfer case.
WHAT KIND OF SCANNER ARE YOU USING?
I would clear codes and see what comes back.

For testing and repair you need some good repair info like factory manual or All data sub.
Also a good transfer case capable scanner and a good volt /ohm meter.
http://www.alldata.com/products/diy/index.html
Also try a batter disconnect or pull fuse.
After code clear post back what code or codes comes back.

I am having trouble finding the root cause of my 4wd issue. I changed the dash switch, the exterior case motor (actuator), and still no fix. all dash lights blink and switch returns to 2whi or auto mode. does not engage 4wd hi or low. codes post to CO383 and CO323- locked circuit low ? I don't know what these mean. does anyone know where to point me? thanks for advice.


the co323 is the transfercase encoder motor is LOCKED OUT....this is because the circuit is shorted/open...remove the leads to encoder motor and check for 18-25 ohms....check wires /connectors,with the ignition key off disconnect the transfercase control module , then with key to ignition on see that the encoder motor tan wire is not shorted to ground...it should have 12volts on it..

if the wiring/motor checks out it's the transfercase shift control module...fuse" atc fuse2 20a " is the power to this circuit..

thank you for that info. toooo cold to get under now, will follow instruction when weather improves. will apprise. thanks, again