I've been meaning to get back on the forum for a while and have today bought another XKR, but a convertible this time, but I'll post about that separately.

My 2001 coupe developed a re occurring P1121 DTC which is quite common and relates to a problem with the pedal position sensor mounted on the throttle body.
I cleaned the throttle body and went through all the other possible solutions such as connections etc. but the problem became so bad it would trip the code and go into restricted performance just sat in the drive and therefore totally undriveable. The prevailing advice is to replace the throttle body but I couldn't find a suitable replacement with the same part number and I was struggling with the idea of simply bolting another worn out PPS attached to another worn out throttle body and decided to take a 'what the hell' approach to the problem.

I removed the throttle body and then removed the PPS and stripped the PPS as far as I could, which wasn't all that far. But I did manage to loosen up the shaft assembly and get plenty of contact cleaner inside and just wiggled and rotated the shaft.

Please bear in mind I wasn't actually expecting any positive results from this and was anticipating having a disabled car, so I'm afraid I wasn't being terribly scientific about it

Anyway, the end result has been about ten months of regular motoring with no repetition of the code, so all in all, bit of a result

Anyway, I hope this may help anyone else with the P1121 code.

Andy

 

Did you take any photos to help others?

 

I'll have a look and see what I did take, but as I mentioned in the post, I wasn't expecting and results and really thought I was wasting my time, so I didn't go about it in a very analytical way. I know I did take some pictures and I'll see what I can find.
Andy

 

So you worked on the PPS on the left of the TB looking out?

 

Yes, it was the PPS, not the TPS. By this stage I had replaced the TPS with a new sensor I found in China and realised my error, as my Autel code reader was telling me it was the TPS but JTIS clearly indicated it was the PPS, which as you say Gus, is on the left side of the TB if you're sitting in the car.
I found the following pics which might help:




Outboard side of PPS showing nut on shaft



Throttle body side of PPS. The arm is moved by the throttle butterfly if I remember correctly



The outboard side of the sensor but with the spring barrel removed

 

That was about as far as could get with it, but what I found was I could get plenty of contact cleaner past the shaft, to the inside of the sensor. I suspect that the combination of the cleaner and my vigorous rotating and wiggling - good technical term - cleaned the contacts sufficiently to do the job. Well............for the time being at least!!
I deliberately decided not to post about this too soon in case it was only very temporary, but so far so good.........
Andy

 

Thanks for the fix and update!