With cascading faults it is always difficult to weed through to the initial source. From what I am reading, however, the pedal control is causing many of the issues. When it says all the pedal circuits are "low", that implies a connector to the pedal may be bad, or the pedal assembly itself. "Low" is normally a disconnected circuit, so a calibration won't help in that case. Not to say a calibration is not also needed after changing parts!?!

The lean code is random and unrelated to the other codes...but would be valid if a seal was not installed correctly when the throttle body was replaced.

I personally would disregard the throttle body fault until the other faults are dealt with...as, with a fresh throttle body, it is more likely a cascading fault unrelated to the body itself. As for the timing chain...it sounds like you do need to plan on replacing the tensioners at some point, as you should not get a start up rattle, BUT the codes have nothing to do with the chain issue. The ECU is unable to read a loose chain.

SO...to summarize, if it were my car, I would start with the gas pedal assembly first. You don't get 4 separate faults on the pedal assembly unless something is going on there! And a faulty pedal assembly will definitely trigger the limp mode.

picked up the car yesterday scanned and p2122 and p2135 came back. As soon as I stepped on the gas ,limp mode. Reset it and limped home. After the 4th reset I made it home about 30miles then turned the engine off and left the key in the on position and stepped on the gas pedal a few times the dash lite up no DSC parking brake fault, engine Fault cruise not available. I checked the codes in the shop manual. Both advised checking the APP sensor (accelerate pedal position sensor) connection and replacing if faults continue. I removed the ,APP sensor disassembled cleaned and reinstalled it. So far no immediate faults. I plan to do a full test drive tomorrow and replace the APP sensor after locating one.

Would that mechanic happen to be Top Line Jaguar?

No sir not top Line

No more limp mode!!! Since I cleaned my APP sensor I haven't had anymore limp mode issues. I'm sure the mechanic new exactly how to fix the problem and figured he'd rip me off first! Pikesville Auto in Md. U.S.��������������������

Good lesson to learn at such a bargain price, do any work that needs done yourself. With all the information available from the advent of the computer, ALMOST any job can be done in the garage at home.