ESP/BAS Warning Light

[TrialByFire]

The ELSD's are actually a gyropump within the diff that creates hydraulic pressure when there's differing wheel speeds. The electronic version of the diffs is actually a solenoid valve which moderates how much of the pressure is applied to the clutches... full open on the valve results in a "locked" diff.

So what is the "whirring sound I hear when I shift in/out of 4LO? Is that the transfer case? I assumed it was the diffs since I can still go into 4LO but no longer hear the sound.

Remind me tomorrow evening and i'll pull out my service manuals to see if you can run a test using a DVOM to see if the solenoid in the diff is stuck or not (usually you can do this by checking the resistance).

I have a DVOM and will remind you tomorrow.

When was the last time you changed the diff fluids? I'm sure MOAB trail riding with some 33" tires put those axles to work... HARD... may be worthwile getting some fresh fluid in there with some friction modifier. As the fluid starts breaking down you'll get more "chatter" than normal from the clutches.

I had it changed not that long ago--January, I think.

[Matt]

That's the t-case shift motor making that sound.

[Matt]

Ok so here's the scoop...

Check the resistance of the solenoids. If the resistance is above 50 ohms:
Inspect the front differential solenoid jumper harness connector, repair/replace as necessary. If OK, replace the shorted front differential solenoid in accordance with the service information. (same for the rear)

If solenoid isn't shorted, there's a whole bunch of tests to do on the control side of the harness... but a lot of them require activating the circuit with a scan tool and checking for output with a test light. There's also instructions for checking for shorts... but it depends whether the DTC is for a high or low voltage circuit fault; and typing up all 40 pages is, well, a lot of work! So see what resistance you're getting and go from there.

If you have a way of pulling the code that would help a lot with the troubleshooting.

[TrialByFire]

Thanks for looking that up. I'll check the solenoids first then see if my brother's reader is compatible with Jeeps.