Hi,

Seeking for some guidance as my 00 XJR is reflecting P0121 code with detail - Throttle/Pedal Position Sensor A Circuit Range/ Performance. The vehicle has a sticky/jumpy throttle and as the code comes up I also get engine failsafe mode, ASC not available etc.

Just a few questions before I simply decide to have it towed to the dealership:

1) Is the error code reflective of just the TPS sensor or am I looking at the whole throttle body being replaced?

2) Are there any steps I can take to see if I can fix this at home? I had cleaned the TB by following the procedure posted here a couple of months back.

Appreciate the input.

 

You could try cleaning the TPS connectors with electrical contact cleaner followed by a hard reset via the battery - the TPS issue has many forum posts in that the dealers want you to buy a new TB for the sake of a sensor.....
I recently had a breakdown with failsafe, trac etc , having recently cleaned the TB , TPS connector and MAF / connector, have been over 600 miles without a repeat (dreaded last words.....).
The TPS connector is a little tricky to disconnect I found so a flat screwdriver to free the securing clip and a little patience....

 

In addition, someone fixed theirs by pushing the throttle through its full
range 50 times a day for several days.

The carbon tracks on the TPS build up crud and the exercising of the
TPS wiper cleans off the crud or at least redistributes the crud.

Prepare for a foot cramp ... full throttle is an awkward angle

edit: some people have also had success by spraying electronic
contact cleaner into the TPS and exercising the throttle.