Often the DSC fault could be a wheel speed sensor, but to read those you would need a reader that can scan C codes. If that would be the issue you would have a code like C1145, 55, 65 or 75 depending on which wheel sesnor is bad. Could also be a rusted relucter ring. If you would do a search on those you will get a better understanding.

As for your misfires, when you changed the plugs did you notice any oil in the plug wells? Could maybe need to change the mainfold gaskets.

For now, don't worry about the catalytic converter. Figure out the misfires first and then see what you have.

 

As Alpha said, the DSC code(s) will affect the function of DSC, which is braking electronically when needed while driving (usually wet or slippery) and does not affect AWD per se. As he mentioned you would need a reader that reads C codes. My preference is the iCarSoft LRII, which also allows you to manipulate each individual module, program modules, etc. The CAT fault is worrisome (particularly if the m.i.l. is flashing) which indicates CAT damage occuring. If the coil wiring is fine, the next check would be as Alpha suggested of gasket leaking oil into plugs.

 

I checked the coil pack wiring as best I could but it basically just goes from the pack into a sleeve that's been heavily taped and I can't really get to it easily so I didn't get very far in investigating that. I used my friend's BlueDriver OBD2 reader and reset the CEL and since then (about ~80 miles of driving) it hasn't yet returned, so that is promising (I hope!).

As for the ABS/DSC situation, my ABS light is on nearly constantly (often waiting until ~30 mph before illuminating for the first time each drive) and will stay on for the remainder of the trip. DSC system fault still on constantly. I was going to look into the location for the ABS speed sensors and check on cost to see how bad replacing them are. I am asking around to find someone with a scanner that can read c-codes for this car such that I can figure out which wheel's sensor is in need of attention. My car needs brakes soon too, so might as well knock them both out at the same time, though I'd really rather not replace all the speed sensors if I don't have to.

My question though, is if the speed sensor is bad wouldn't it always illuminate the ABS light and not just activate a DSC system fault?

I greatly appreciate the helpful advice and explanations you guys provide here, thank you so much!

 

Dell,

My Check Engine Light came back on the day that I returned my friend's OBDII Reader. It didn't light back up the entire time I had the scanner. I didn't have it plugged in for three or so weeks and had no issues with the CEL. I haven't had a chance to get it scanned again, but I'd guess it's going to tell me misfires on 1,3,5 again. Putting this issue on hold.

My DSC situation has gotten worse (I think?). ABS light comes on more frequently, occasionally the BRAKE light (normally illuminated when parking brake is engaged) will come on when driving. My car does need new pads and rotors, but I'm wondering if it's most cost effective for me to replace all of my ABS sensors for <$100 when the scanner your recommended is $150+. My only concern with this approach is that I won't be able to clear any codes after I replace everything and also that if the ABS module is the problem, rather than the sensors, that this will remain unsolved.

Do you have any advice for me moving forward?

 

Idk, the scanner is a little pricey, but you'll be happy you have it in the future if another challenge arises. As I mentioned, you can manipulate things with it, like evap sensors, wheel sensors, etc. Clear codes (any cheap one can do that), program some modules........saves guessing when you can pin point the exact cause(s) and saves guessing and throwing parts ($$$$).

 

I would definitely buy a scanner just to have as it could be so helpful in diagnosing future codes not only for the Jag, but cars you would have in the future. Think of it as as you would a good set of tools. Pretty much indisensable if you ask me.

Find it hard to believe that all four wheel speed sensors would go bad at the same time, but not the most expensive thing to replace and not the most difficult of repairs, so it sure wouldn't hurt anything to replace them. After all, the car is 14 years old and things just wear out after that amiunt if time. What I can tell you is that situation will not just go away and as you are finding out, will only get worse. Just bite the bullet and buy teh code reader and then teh speed sensors if that is what it tells you and be done with it. The longer you ignore this the more frustrated you will become.

 

Check your wiring to the sensors, too. Old car, old wires, get chaffed - brittle - got hit by debris, sometimes it's that simple. But I bet on speed sensors.