P0001 code
 

No info on a search here. Google says basically manufacturers don't use this code that it refers to something else. The most prominent source of the code per Google is "wrong code reader." If it is specific, it is for "fuel volume regulator open." I'm not sure what that is.

Once again, no info here on such a thing. Symptoms include occasional rough idle and stumble. I've been thinking O2 sensor, but I can't just start throwing parts at the thing. One other symptom I've noticed this summer is if the car sits out in the sun and gets very warm (like 120º), it starts and runs rough for a quarter mile or so.

Comments? Oh, and I'll admit to using the high end HF scan tool. Works for a lot of cars. Maybe not this one. But that's a separate subject.

If you have the high end scan tool, then chart the LTFT STFT and calculated load and figure out what is happening.

Hey Milt,
:icon_idea1:
Did you get a check engine light before you connected the scan tool? And did you reset it? If so, the code might simply mean the drive cycle (readiness) is incomplete. My XJ12 always shows P1111 for drive cycle complete, with no check engine light.