2003 service 4wd

Hello
I have a 2003 Tahoe that is getting a service 4wd message on the dashboard (aka DIC) I hooked it up to a code reader and no codes. Also the 4wd is working although it seemed to make a clunk noise when engaged and disengaged.
Thanks for any help before I bring it to the dealer:crying:
Tom

Have you checked the fluid levels on the Transfer Case and Front Differential?

Most "over the counter" code readers will not access the 4WD system module. Need to get it to a shop that has a scanner capable of getting into the 4WD system module and pull the codes. Post back the exact codes when you get them and someone here may be able to help.

Hello
I have a 2003 Tahoe that is getting a service 4wd message on the dashboard (aka DIC) I hooked it up to a code reader and no codes. Also the 4wd is working although it seemed to make a clunk noise when engaged and disengaged.
Thanks for any help before I bring it to the dealer:crying:
Tom

replace the transfercase fluid lately????what color is it????
If thefluid is not blue and clear you need this replaced...it costs 100.oo to get DTC for drive train measured if the 4x4 works this then usually means the switch on dash needs replacing or solder joints need re soldering...this switch is much cheaper than the DTC diagnostic...this happened to me and a forum member suggested this and with the fluid tracII change, two flashes and it goes into 4x4 unnoticed....