Driving home from work last night I had the above warning messages but no check engine light. The vehicle would not accelerate at all, I was in the fast lane and almost got taken out as I tried to coast over to the slow lane and onto the shoulder of the road. Not an easy task on California Highways. I put the vehicle into park and then noticed a space just up ahead with a little more room so I placed the gear selector into drive and banged into gear, I immediately tried reverse and the same thing, bang. I proceeded ahead and went to the trunk to retrieve my SCAN TOOL and found codes P0121 and P1111. I'm already familiar with P0121 having read about it on this forum and also know P1111 is no problem found. But isn't this a strange combo? I cleared the codes and was able to proceed a short distance when the restricted performance warning happened again. By this time I was on an off ramp but still could not accelerate. I quickly scanned again and got P1000 only. I was able to turn off and restart and finally made it home.
What I also noticed, starting a few days ago is my average fuel mileage had gone from 21.2-21.4 down to 20.1-20.4. I always use 76 91 octane fuel and have filled up at the same station for months now. Anyway, I don't know if there is any relationship here but I'm wanting to note the observation for others none the less.
Tomorrow I'll be taking a look at the connectors and will report back here what I find.

 

Load test the battery.

 

And if/when it passes?

 

There may be another code that your scanner doesn't pick up. You really need to get the codes read by a dealer-level diagnostic system; IDS/SDD, Autoenginuity, etc..

 

P1111 does not mean no problem found. It only means that all the OBD monitors have run completely at least once. Any actual errors flagged after that just leave the P1111 unchanged.

Could easily be the battery.

 

Battery passed load test, and just for the sake of being complete the warnings don't show up on start up. The issues occurred after driving 8-10 miles. So I would think unless the battery had an internal short or the car a large paracitic draw, that's also intermittent, I'm ruling out the battery at this point. Anyway, later I'll be looking at the TB/TPS harness/plug/wires.

 

OK, just finished poking around inder the hood and this is what I found/did. No noticeable signs of corrosion on the TB connectors. I did however clean them and the female side of the connector with a dental flossing pick. Also cleaned the MAF and MAF connector. What I did find however was the lock to the connector for the TB servo motor(?) was broken. I had the thermostat housing replaced several months ago and I'm pretty sure they would have removed the TB to do the job. In any case I placed a zip tie on the plug to hold it secure. So now I'll have to drive her, with caution, and aee what happens next.

 

Just went for a drive as I needed to go to the grocery store and get some gas. I had also forgot to mention I did a hard reset on the vehicle. Disconnect battery, turn ignition on and off, touch battery cables together, turn ignition on and off, reconnect battery and start engine letting it run for 10 minutes.
The vehicle seems to be running and accelerating well, better than it seemed before. The gas average gas mileage showed a steady increase a tenth at a time well past the 20.4 mark I had been getting for the past several days. I had gotten to 24.7 and about a 9 mile trip up and down the highway. Which is about right given the average I'm used to in city/highway with traffic. At this point I'm not considering the problem solved and will of course be monitoring the situation.

 

Don't you just love zip-ties. Nearly up there with Gaffer tape!!

 

Thanks Don, keep us in the loop please.

fingers crossed

 

Maybe time to change the shop who does your servicing ?

 

Trust me I've been thinking the same thing. It's the only Jaguar dealer that even close to convenient to drive and still far out if my way. I've tried a few Jagaur specialist (indispendents) but I was not impressed at all. My problem is I don't have the time or desire to do my own repairs any longer. Used to do everything myself, from oil changed to engine removal. Looks like I might just go back to being a full time DIYer.