[Andy Lonewolf]

15 March 2023: Good Morning, I am new to this group, I just have a question? I have a 2018 Jeep Renegade and this morning the service 4 wheel drive light came on, this isn't the first time this has happened, The last time was a few months ago but it went out by itself and hasn't came back on until this morning, Just would like to know why it is on, What could be the problem, How expensive it may be to fix it depending on what it is and is it safe to drive my Jeep with it on until I can get it fixed? 🐺

 

[Marek K]

Welcome!

According to my 2021 Owner's Manual, that warning comes on "to signal a fault with the 4WD system. If the light stays on or comes on during driving, it means that the 4WD system is not functioning properly and that service is required."

Key is, "if the light stays on or comes on during driving." I assume it did, during driving...?

One quick thing to check is, how old the battery in your 2018? The 4WD system is bery much electronic; and a weak battery can cause all sorts of weird electronic issues. Three years old seems to be time to start thinking about a new battery.

That's not always the problem, and older batteries have often worked fine. But it's the first question to ask.

Otherwise, looks like it needs to be taken in for service. There's nothing to indicate that it's unsafe to drive; you just obviously won't have 4WD.

 

[Andy Lonewolf]

Welcome!

According to my 2021 Owner's Manual, that warning comes on "to signal a fault with the 4WD system. If the light stays on or comes on during driving, it means that the 4WD system is not functioning properly and that service is required."

Key is, "if the light stays on or comes on during driving." I assume it did, during driving...?

One quick thing to check is, how old the battery in your 2018? The 4WD system is bery much electronic; and a weak battery can cause all sorts of weird electronic issues. Three years old seems to be time to start thinking about a new battery.

That's not always the problem, and older batteries have often worked fine. But it's the first question to ask.

Otherwise, looks like it needs to be taken in for service. There's nothing to indicate that it's unsafe to drive; you just obviously won't have 4WD.

Thanks for the information, When my Wife drove the Jeep to work this morning the service 4 wheel drive light was on and when she got off work she said it went off and could engage it in 4 wheel drive, Something we will have to keep an eye on, And also a good point you made about the battery, We never replaced it since we bought the Jeep new in 2018, That's something else I need to consider. 🐺

 

[Nev]

Check and reseat all the connectors on the internal fuse panel. Sorted the occasional 4WD Serv I got.

 

[Marek K]

Check and reseat all the connectors on the internal fuse panel. Sorted the occasional 4WD Serv I got.

You mean the panel under the driver's side dashboard? Doesn't look easy to get at it...

And by "connectors," you mean the fuses? Or the electrical connectors behind it (even harder to access)?

 

[Nev]

Yes, It's easy to get to if you take the lower panel off. Connectors & Relays on it. Spade fuses seemed pretty tight. But no harm pushing them all home too, I guess.

 

[Marek K]

Yes, It's easy to get to if you take the lower panel off.

I did once -- take the lower panel off, looking for my security gateway. Here's the fuse panel way behind there, with the mostly yellow fuses:

I wouldn't call that easy to get to. Who designed a vehicle with the main fuse panel that hard to access? Oh, yeah... the Italians...

 

[Nev]

It's behind the glovebox on UK versions. 🤭

 

[Mrsig]

and enjoy the forum!

 

[Mrsig]

and enjoy the forum!

 

[Marek K]

It's behind the glovebox on UK versions. 🤭

Yeah, now that you mention it, I seem to remember that. So on the left side, no matter what world version.

And that's strange. Normally the main computer is under the dashboard on whichever side the steering wheel is on, like the OBD2 port; and that fuse panel would logically be near the computer.

And the glovebox side is taken up by, well, the glovebox; and the cabin ventilation stuff (motor, cabin filter). You'd think everything would be flipped for RHD vs. LHD...

 

[raz-0]

The service 4WD message is practically a catch all.

Probably the most common is just ground issues. So bad battery, bad ground strap, etc.

Next up would be bad sensors. The most likely of those is a bad wheel speed sensor. But basically anything that deals with how fast wheels are spinning, transmission is spinning, what gear something is in, what position the motor in the RDU is in, etc. Basically if it can't tell what the 4wd system is doing or it can't get enough info to do the math for traction control or stability control functions it turns the 4wd system off.

It will also disable the 4wd system if there are other faults simply to protect those other systems as the 4wd system stresses more thangs than running in 2wd.

Or it could be gremlins. The thing is service 4wd typically doesn't come up alone, but paired with other stuff, and the other stuff is more informative.