This started yesterday: had been in the car for about 40 minutes idling at night when suddenly I got the following faults: Engine System Failure, Cruise Control Unavailable, and both amber and red warning lights as well as a CEL. I also noticed rough running and rising revs. I turned off the car, waited a couple minutes and the faults cleared.

The symptoms returned this morning when I was in the parking lot of the university. This time I was able to use the code reader and got P0121. I think this may possibly be the TPS? I can’t seem to find the part number for the throttle position sensor.

 

I think you are on the right path. Had the same problem with my 2000 XK8 and it was the TPS. On my car the part number was right on the part. It is a Denso part and is also used by Toyota on their TBs. As you car is a 2004 XKR I believe your TPS is different than mine. Good Luck.

 

Ok, I will check my TPS when I clock out of work. I hope mine also cross-references with a Toyota.

 

My TPS is: Denso 198500-3300. Apparently nigh on impossible to source without the Throttle Body, locally at least. I found a near identical unit from a ‘98 Geo Prizm on Rockauto. Is that the one you bought?

 

I was able to get a TPS with the exact same part number on eBay. The TPS came from China and I think it was rebuilt but it worked fine. If the one on Rock Auto looks exactly the same it maybe worth a shot, you could always send it back.
r

 

Thanks! I was able to source an identical one on autozone cross-referenced to a ‘96 Camry. However I am having trouble removing the original one. My T-15 bit is not going in. Not even the tamper proof one. T-10 is too small and T-20 is too big. The bolts do look corroded. I will attempt to wire-brush them before I go nuclear and just remove the TB.

 

This is unusual but it requires a different tool. Now that you mention it for some odd reason they use a connector that requires a uncommon tool. Its not a jaguar tool but it has a relief on it or something that allows it to work. I got a set at Harbor Freight when I had to deal with it. I will look in my tool box to see if I can remember what it took. If a recall the "bolt" has a lump on it that fits into the tool you need and will not allow the standard to work. I now recall it is a Hex T-10 or so with a "cup" that allows it to work.

 

My torx and security torx don’t seem to work. I wonder if it’s a Polydrive or triple square instead?

Do any of these look like what you used?

 

On my car I am pretty sure I used the 6 point security torx. However on going through my tool box I found a set of 5 point security torx. Not sure what they are for. If you can see the head ot the torx bolt perhaps it is a 5 pointer.

 

VW uses the 5 point Torx bits on their MAF sensors. Got mine on Amazon as inexpensive ($10) set that fits in a 1/4 driver. VW seem kinda over engineered. :-)

 

I gave it a good look with my loupes right now. It is in fact a 5 point torx bolt.

 

I have learned that these sensors, even if they look the same, the internals are different. I tried one from Autozone, one from Toyota Camry, a one from Geo Prizm, and none worked.

There’s one from a Mazda Protege made by Denso, but the last 3 digits of the part number differ. At this point I am hesitant to try it out.

Does anyone know of a reliable reseller

 

https://www.ebay.com/itm/222400767398

 

I ended up purchasing that one even though it's all the way in china. At that price I don't mind throwing away that money.