The P1229 code means that the throttle motor (or stepper motor), is probably not connected (or right).

So the ECU is then not able to adjust the idle as the relax butterfly opening is slightly more than for the normal 600 rpm. It then tries to control the engine rpm via fuel control, so it will not idle nice, and will be normal behavior.

Can you do a test?;
Have someone look at the TB butterfly when you turn the ignition on. At that time the ECU will check the TB by closing the butterfly. If nothing happens, there is a power failure of some sort, and the ECU will then stop trying to control the TB butterfly (so you can move the butterfly/and will not hear the motor anymore.

 

I just re-read all the posts and now have the names down, a little. For some reason, I thought that the original problem was for an '00 engine, but it's really for an '02. So, this TB that I have wouldn't have worked anyway. But, if there's someone out there that needs a TB for an AJ26 SC engine, I have a very slightly used new one that's been sitting in my garage, in a nice plastic bag, since December of '03. That's when I crashed and totalled out my '98 XJR after putting the new TB on a month before.

BTW, from my first post last weekend ... I replaced the hoses on my purge system and the car runs really good. I had to make new hoses from 3/4-inch fuel line, since I couldn't locate OEM replacements, other than having to buy the whole pieces for an outrageous price. Cost me $32 for hose and clamps. So, if anyone is having intermittent check engine lights and a P1443 code (I think), check those hoses. Mine were so bad that the outer covering was crumbling.

Sean B - you mentioned that you have a full Paramount exhaust? Does that include the headers and Cats? If so, send a picture ...

Have a good day and a good weekend !!

Another BTW, my real name is Mark

 

Sounds exactly like what is going on at the moment with my car

Now I am confused, that does not seem to match what the previous posts said While the car is on/ACC but not running, the butterfly should open-and-close with a change in the throttle. At rest the butterfly always seems to be closed (car on or off), is that normal? I never tried moving the butterfly by hand, I assumed it would de-calibrate the stepper motor.

 

You only need to look at what the butterfly is doing when you turn on the ignition.

If the ECU has detected an error (which P1229 clearly is), it will not power the stepper motor anymore. In this situation you can move the butterfly, but I am not saying you should, it was merely to to say that it is normal behaviour that in this situation the butterfly will not move.

So have someone look at the butterfly, turn on the ignition (nothing else, so don’t even push the pedal), and look what the butterfly does.

 

Third one is the charm - wooooot! Drives beautifully, idles nicely at around 800rpm cold and 600 at normal operating-temp.

Need to put some miles on it now and really confirm that it is working, if so, bought some strap-ties to adjust the throttle cable (which still has some slack in it.)

 

Very good!

 

Kudos to you! Back on the road again.