Well I'm weeding thru my to do list on my new 99 XJR and although I think I can get her thru a New York state inspection with a traction control and an ABS warning light I can't really leave these on. In our 540i these faults would just light some fairly easy to get used to idiot lights but the jag is practically screaming at me with this cycle of messages.
I've seen some mention of ABS module issues but was wondering if people had found any issues with wheel speed sensors or other parts of the system. Will one issue cause both messages to scroll across the lower reaches of the speedo? Is there a good point to diagnose whether things like a whel speed sensor are behaving properly?

 

I haven't looked at mine, but I know the wheel sensor in my 328 does trip those lights also, so it might be worth just trying to clean the sensor prior to replacing, it might at least give an indicator of if that's what's tripping the faults. I'm sure there's a post here somewhere regarding them, but I don't have that issue. My other one though, that sensor is toast but I know that's what is causing my ABS and TCS to flash at me.

 

Cleaning sensors #1. Here is a sheet to help trouble shoot. If you check resistance of the sensors and cables from the big multi plug expect 1020-1660 ohms.

http://jagrepair.com/images/AutoRepa...heet%20XK8.pdf

 

Yes a bad wheel sensor will cause both those message to display. The short cables connecting the front wheel sensors back to the wiring on the frame are the common culprits. On my car it was the passenger side cable that went bad


The troubleshooting diagram from RJ will help you find the problem

 

I should have warned to disconnect the negative battery cable before unplugging the module. This is important for doing any electrical work as it avoids causing a voltage spike that could result in expensive damage to the modules.

 

RJ237,
Thanks for the diagram on the ABS wheel speed sensors. I disconnected the ABS module and read the resistances for all 4 today and the all come up 1.14K Ohms. Sounds like I need 4 new sensors but I guess I'm suspicious that they would all be the same. Was there a change to the parts for the 99's? I'm going to clean the sensors next juts to see if one is crudded up and not seeing the cogs on the hub but thought I'd ask about the resistance measurements as these little guys are pretty steep ($145 each was the best price I found).
Doug

 

Those readings are good. My error. I should have said 1100-1160 ohm, which is 1.1-1.6 K ohm.

 

If you were to have the codes read by a independent shop that can read jag specific codes, the reason for the light would be explained.

If I had to guess, I would say it's the cold solder problem at the pins to the abs pump. This has been covered many times, and can be repaired easily be many online services, or by yourself if you're able to remove and open the abs module and use a soldering iron.
My preferred method is to drill a hole in the case, but you need access to a drill press:

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