Service 4WD message

[possum328]

This just came up on the DIC in my 2004 Suburban. 4wd is now inoperable. Any thoughts as to a “usual” cause?

 

[jhellwig]

Is it actually 4wd or is it awd? They operate very differently.

4wd had a hydraulic clutch in the transfer case for the auto operation and an actuator in the front axel. The awd system has a whole bunch of stuff that can go wrong.

 

[AVB]

It could also be the switch, my 2003 Avalanche acts up from time to time. Sometimes it will start off in 4lo.

 

[TurboTravis]

Do yourself a favor and replace the dash switch and encoder motor (actuator) at the same time. Either one or both is going bad. Trust me, I went thru this last year, started with the switch, eventually replaced the actuator. When this stuff acts up, it can leave you stranded in 4 low at random times and all other kinds of fun stuff.

 

[c502cid]

What Travis said is really the way to go but if you are handy at all with a soldering iron you can try just reheating the solder on the back of the dash switch. They become brittle with age. I've repaired two different trucks this way with the same service 4x4 message. It's free to try it.

 

[MasterTech58]

The 'Service 4WD' indicator is like a 'ck eng' light for your drivetrain. There should be a fault code stored in your transfer case module to tell you why.
If like Chrysler, there may be 'final drive' module software updates to 'fix' the problem. Always diagnose first if you can.

 

[possum328]

Thanks all. The problem has disappeared, electrical hiccup maybe? Good advice if it returns though.

 

[TurboTravis]

I would at least repair/replace the switch..trust me, it will come back if you dont address it.