my service 4wd light came on replaced the push button switch and now nothing on 2000 GMC Sierra 1500

had the truck pluged into computer and is not reading any codes or 4wd at all what could be the problem checked grounds and im at a loss now of what to do

by in South Thomaston, ME on November 01, 2013
3 answers 1 comment
ANSWER by on November 01, 2013
Need a different scan tool, generic tools only scan emission codes. Need a more professional scan tool to read the separate modules, like the 4wd module. Just a quick idea had one that the cigarette lighter fuse in the under hood fuse box was blown, of course it didn't power the DLC connector. I use a Tech2 on GM vehicles. Probably need encoder checked.
ANSWER by on November 01, 2013
have its scanned with a tech 11 scanner to get codes
COMMENT by on November 01, 2013
It was a professional place and tool i believe. They said they could try the something else on another day. If it was something not too difficult i can do on my own but dont own the computer stuff.
ANSWER by on November 01, 2013
I just did one last week and you really do need the TechII for diagnostics on that system. On the one that I had the module itself had failed and it wasn't communicating on the data bus with the other modules and having the factory tool allowed me to see that right away on the class2 message monitor and really made the diagnostics much easier.