After a fantastic round trip through the Rockies last season I've been experiencing unusual, unexpected and unwelcome intervention of the DSC or Dynamic Stability Control when I navigate sweeping turns. The phenomenon manifests itself by activating the brakes (loud grumbling) and generally upsetting the cars balance (the opposite of what I would expect it to do). It does this in the wet as well as dry and is most obvious on sweeping interstate exchanges. The only time I have previously seen the DSC engage was on the way to Colorado when cornering graded dirt roads at speed.
I've checked the easy things - tire pressure, ride height, tire condition (all new-ish), bearing and joint health, and even replaced the air struts and had the car four wheel aligned - the condition persists.
Any thoughts on where to check next?

 

I would suspect a faulty wheel speed (ABS) sensor. Do you happen to own a diagnostic tool that would allow you to monitor the sensors?

 

Have you ever changed the transfercase oil?

 

Holy crap! You dropped what must've been about $3500 (dealer price) on all 4 air struts for that? ...and it persists? You must be going nuts.

Wheel speed sensor issues usually come along with a suite of faults not unlike that which comes with the brake switch going ****. Are there any other things happening? Good suggestion to get a code reader. An IIDTool from GAP Diagnostics is about $400.

Have you at least taken it to the dealer and had them plug it in and read codes?

EDIT: Wheel ANGLE sensors cause a myriad of faults. Not sure about wheel speed sensors...anyone?

 

A guy on defendersource that has an LR3 had similar issues when he had a worn through harness to a wheel sensor.

 

Clarification; I didn't drop $3500 on air struts to address the problem. I was getting leakage out of two of the struts and because they were going on 110K miles I decided to replace them all at once so I didn't have to do the alignment multiple times. (more like $1300 total) - By the way its a pretty straightforward job that, if you can twist a wrench and have dexterous fingers, can be done in a few hours.
In any case it didn't help with the problem.
How might the wheel speed sensors relate to the problem?

 

Wheel speed sensors talk back to the ECU and when readings are not within spec it cuts stability control (same thing with other manufacturers not just Rover). Sometimes you can just pop the sensors out of the hub and clean them up. They are magnetic so they pick up stray bits of metal that can distort readings.

 

The air struts are about $500 a piece (average of all 4) so how did you do it for $1300?

 

If a wheel speed sensor has failed, you will also have a CEL, with code P0500, but that is only if it has logged a fault, if it is reading incorrectly at times, it might just act funny.

You may want to check the condition of your wheel bearings as well, as the wheel speed sensors' reluctor rings are built on to the end of the axle shafts, so play in a bearing can cause the ring to move out of the way of the sensor.

The steering angle sensor can be checked easily if you have factory fitted nav, by going into the 4x4 info screen, and watching it move in relation to how you are driving. If no nav, you should be able to see something similar on the instrument cluster's message center when you select mud/ruts TR program, but it isn't quite as good, and you will be driving in a different program at that point, so use care(I don't recall if it shows up on sand on the LR3)