The "Service 4WD" Light lit up. Made it home shut down the truck, restarted and it stayed off.
Is the warning light a mileage driven thing or are there sensors in the xfer case and 4WD train
detecting? If its a sensor thing, what sensors are coding? I gotta have 4WD in mountain snow.
Any help appreciated

 

Just for the heck of it, it might be nice to know details of your truck!

 

My '17 3500 would suddenly go into 4wd even on the highway while towing and then the service light would come on. Turned out to be 4wd module, about a $750 part.

 

Hi,

The "Service 4WD" light indicates a potential issue with your four-wheel drive system. It's not based on mileage but on sensors detecting problems. These sensors can be in the transfer case, 4WD actuators, or other drivetrain components. It’s best to have it diagnosed by a professional to ensure your 4WD is reliable for mountain snow conditions.

Jack

 

The Service 4WD light usually comes on when there’s a problem with the 4WD system, such as a sensor issue, wiring, or mechanical fault. It’s not typically related to mileage, but it can be triggered by sensors in the transfer case or other parts of the 4WD system.

Here are some possible causes:

4WD Shift Motor: This motor controls the shifting of the 4WD system. If it’s faulty, it can trigger the light.

Transfer Case Position Sensor: This sensor tells the truck what mode the transfer case is in. If it’s not reading correctly, it can cause the light to come on.

Wiring Issues: Sometimes, wiring to the 4WD components can get loose or damaged.

Low Fluid: Low transfer case fluid can also cause the light to appear.

To fix it, you may need to get a diagnostic scan done to read any codes stored in the truck’s computer. This will help pinpoint the exact issue. If you still need 4WD, it’s important to get it checked out soon to avoid being stuck in bad weather.