Jon,

There's a lot of good theory in this thread so far identifying possible / probable sources of the issue but it's not targeting specific components.

In the absence of buying / borrowing AutoEnginuity with the Jaguar Enhancement Pack or Mongoose, do you have anywhere local can read DTC 'C' (chassis) codes?

I know you're familiar with DTC 'P' (powertrain) codes and how useful these are when pinpointing a component or circuit fault. The DTC 'C' codes are equally detailed and can pinpoint specific module / sensor / circuit faults in the Dynamic Stability Control system.

Graham

 

Graham,

I do not know of a local source to read the C codes on my wife's XK8 other than the Jaguar dealership. If my relatively simple and low-cost efforts to resolve this issue as part of the upcoming 60,000-mile service do not pan out, my next step will be finding someone who can indeed read the C codes....

I may have temporarily resolved the issue Sunday afternoon simply by unclogging the two small holes that were blocked in each of the front sensors. The car has behaved normally since then - no warning lights, messages, brake pedal pulsations, or clunks....

As always, thanks for your feedback. By the way, have you resolved your Code 17 airbag dilemma?

 

Jon,

The success of your sensor cleanup sounds as if this could be another consequence of the 'greasy grime' incident and nothing more serious. I hope so.

I'll swap you for a Code 17! Having eliminated all the sensors, the Instrument Pack and the SRS module by substitution, I'm left with a possible harness fault and to trace this I'll be tearing out the interior once the weather improves.

Graham

 

I'll keep my fingers crossed for you. Such a shame to have to rip out your interior to locate and replace faulty wiring due to these complex electronic faults. I hope you discover the cause quickly and fix it permanently....

 

Update:

As part of my 60,000-mile service performed yesterday, I took the following actions on the wheel speed sensors:

1. Pulled and scrubbed all of them again. Could not believe that the two front sensors were already beginning to get a build-up of dirt and grit in a couple of their small holes after only five weeks and 1,500 miles have passed since I last cleaned them. Reamed out the holes again with the end of my trusty paper clip.

2. Cleaned all electrical connectors with a spray can of Contact Cleaner purchased from Radio Shack.

3. Cleaned all cog rings with a spray can of Brake Cleaner purchased from WalMart.

4. Removed the electrical tape I had wrapped around the two rear harness rubber boots that had split open, cleaned the area well, then filled and covered the split rubber boots with multiple layers of Clear Neutral-Cure Silicone Caulk purchased from Lowe's. Allowed the caulk to cure for three hours before re-installing the rear sensors and rear wheels. Allowed the car to sit overnight to ensure complete caulk curing.

I test-drove the car this morning for nearly ten miles at speeds ranging from 25 mph to 90 mph. No issues, no warning messages on the dash.

I had planned to perform these actions at every oil & filter change / tire rotation interval of 6,000 miles from now on. Judging from the quick dirt-and-grit build-up in a couple of the holes on the two front sensors, that may not be often enough. Time will tell....

My recommendation is to check your wheel speed sensors every time you pull your wheels. It's easy - remove one 8mm bolt, unplug the electrical connector, and the sensor is loose in your hand. Bring a paper clip with you and you can ream out the four holes in less than 30 seconds....

 

Update:

My wife has driven her XK8 right at 1,000 miles since I r&r'ed her wheel speed sensor system not quite three weeks ago. Absolutely no issues or dash warnings since....

This serves as just another reminder to check your sensor harness rubber boots (along with the condition of the speed sensors themselves) whenever your wheels are off the axle for rotation or brake work. If those boots are split and cracked (and I'll bet that they are), seal 'em up tight after thoroughly cleaning them. I believe this will resolve a lot of dash warnings out there....