Take off both battery cables. Take both the positive and negative cables and hold them together(make sure they are not touching the battery) Keep them together for about 20 min. This will clear out any and all memory that may be left in the car. If the lights. Are on problem is not fixed. Best bet after that is to get a code reader.
Hope this helps,
The Dr!

 

THANKS to everyone who helped me lick this. Here's how it turned out.

I bought the tubing with check valve that runs to the brake booster and an Actron 9575 and before installng the tubing I found out that the 0171/0174 codes were gone but another one had cropped up. I think it was P01000 about a loss of fuel vapors.

So, I took the tubing back to Jaguar and saved $98, about the sale price of the Actron. The P01000 code disappeared on its own - was possibly a loose gas cap.

Thanks again to the guys who answer all these posts. You're very knowledgeable and generous with your time.

Bob

 

Bob, glad you got it sorted, but P1000 is for a system check meaning everything is good. Hopefully what you did so far solved things, but don't be surprised if something comes back if it is an intermittent vacuum leak. Hopefully not!