good evening.
I'm new to the forum and I write from Italy.
for about 5 months now the SERV 4 WD warning light comes on.
The light does not come on according to a very specific logic.
sometimes it comes on as soon as I start the engine, other times while I'm driving.
at the same time as the error message the key where the car axles is shown flashes.
if I press the tachograph button, the message disappears ... but then comes back.
I have read many posts from previous years, with users having the same problem as me.
I wanted to know if the problem has been identified over the years, as many users have the problem with this damn SERV 4WD.
could it depend on the wiring. of the cables that are in the hub of the cliff?
thank you very much and all users.

domenico.

 

scan and post the code(s)

 

Hello Domenico, tell us what year/model your Hummer is. Are you able to have the truck scanned using the OBD port to get error codes?

 

There are some great threads that cover this exact problem.
I know I myself have posted a bit.

Search is your friend.

 

unfortunately I don't remember the error code in mind. I would have to take the car to the mechanic again. the problem is that NO ONE within 100km has a diagnosis for GM. I thought that someone with my same problem had solved the problem in some way. to update you. in the meantime I am waiting for some response from some users. thank you very much

 

 

Well yes, i did have the same message, only the Serv 4WD light. After changing oils (from my transmission and transfer case) the message was gone and never came back. No error codes found.