Well, kids, about a year or so ago, was having many error codes. They led to replacing the timing chains/tensioners/slippers... the who shebang... thank heavens one of my best friends is a master machinist, and helped me along with that project... Car has served me well since that time, but of recent, have been getting "Restricted Performance" message. Tried checking it with my Code Reader... no link. Thus, took it O'Reily's today in "restricted performance" mode to see if their's would read it. Oh, and, did it ever.

Codes:
P0102
P0112
P0300
P0304
P0305
P0354
P1111
P1313
P1314
P1316

I've researched all the codes, meanings, what it could be. But... just where to start??? Car was a one owner, 85,000 miles, Jag serviced when I bought it from original owner about four years ago. Currently has 124,000. And, yes, I've read every post I can find on here.

Appreciate any and all suggestions. I just don't want to go throwing parts at it in an attempt to diagnose the real problem. I've read many of the threads here regarding this issue, with solutions from fuel filter, to coil packs, to throttle bodies, etc... Gee, my MG is so much easier to diagnose...

HELP??? Suggestions???

 

That many codes makes me suspect a weak battery. The first thing I would do is get a code reader and erase the codes, then charge the battery overnight and see if any/all re-occur. You can connect your smart phone to the car very inexpensively. Do a search here for code readers.

 

+1 for rj's recommendation. The biggest clue is P1111 meaning everything is OK. Obviously that's an old code and a lot of the others may also be old.
Clear them, make sure battery is good and now we have a starting point.

 

Thank you all for the suggestions.

Well, I had a new Interstate put in a year ago. As for charging, it's been on the battery tender for the last week, and the negative cable disconnected, in order to try and "reset" things, as my code reader would not link.

So, after having O'Reily's read the codes today, had them write the codes down, erase codes, and drove it home 3 miles. Not long after leaving the parking lot, "Restricted Performance" showed up again... arghhh...

So, here we are again. I've also checked all the fuses in the car as well. All good there.

Thought maybe a fuse could be preventing the code reader from working... happened to my wife's Buick before... no luck on the Jag...

 

If the battery was OK you have multiple faults all at the same time so study the workshop manual in case you can figure a common cause.

E.g. P0304/P0354.

 

Need to reset the codes -- have all cleared and read the codes after first RP event. I have an inexpensive reader .. surprised you are having issues linking. You have to have working code reader.

Another idea is to move the throttle throughout its range -- push the gas pedal to the floor 50 times. The T body's sensors are a known problem -- any dirt / corrosion on the pathway will trigger a fault. I had a PPS fault many years ago that went away after this was suggested. I give mine 10 at lease once a week.

 

Okay, kids, just an update on the most recent saga with the 2001 XJR. In spite of all the codes, and the fact that my Bosch OBD 1000 would not read the codes (had O'Reilly pull all the above), I broke down and spent another hundred bucks for another code reader... (the OBD 1000 works fine on my wife's '02 Buick, and my buddy's Nissan).
Well, after fussing and fighting, and researching this thing... FINALLY figured it out today.
While trying to diagnose what turned out to be the timing chains a year ago, my mechanic suggested I buy a coil pack, and use it to diagnose that first. Well, it wasn't the coils, but, I still had that coil pack laying out here in the shop. And, while many codes were related to it, I'm thinking the P0304, P0354, etc... were the key.
Researching the codes led me down many a path, but, the P0354 led me to check "Ignition Coil D", which was cylinder 4. After installing, cleared what codes I hadn't, and got rid of the dreaded "Restricted Performance" mode.
Just got back from a test drive of about 15 miles, the last few, kicking in the Supercharger a bit just to be sure. She's purring like a kitten again.
I live in the stix, so, upon reaching my road, which is only a mile and a half from my house, dark and desolate... I decided to push my luck, put it in Sport Mode, power braked it, burned some rubber... only to have "Restricted Performance" come on again.
Well, just pulled it back in the shop, popped the bonnet, and, lo and behold, I suppose the torque of the engine pulled the MAF sensor connection loose. Plugged it back in, cleared codes... all is well again... looks like I'll need to zip tie the MAF sensor connection together, as the 16 year old plastic clip is no longer doing its' job...
Thanks all for your suggestions.
Rod

 

It's always the simple things that get you. Glad you got that sorted for now; I'd also give the plug and the connector on the MAF a light shot of contact cleaner, just for good measure and work the plug in and out a couple times gently. Like chicken soup for a cold 'it couldn't hurt'; these cars don't have gold plated connections (well, iirc, there was an update for the cruise control that DID include gold connectors), and after all this time and heat and schmutz, it's probably due for some TLC.

 

Yup, did that as well, along with a bit of silicone grease to boot...
Regards,
Rod

 

You might want to check your engine mounts just to be sure that there isn't excessive movement of the air tube and electrical harness tugging which may have caused that MAF connector to come undone.

 

Addicted2boost...
Thanks, and a very good point... I'm getting ready to rebuild front and rear suspension, as tires are wearing on insides, and shop says there's no adjustment left... I'm thinking about replacing all mounts at the same time. Which leads to another post...