Throttle Position Sensor (TPS) on 97 XK8
 

This message is for owners of a 1997 model year Jaguar XK8 coupe. My vehicle
is VIN production #: 008880. Have any of you had to replace the Throttle Position Sensor and/or Throttle Body on your vehicle. I have been told that it is impossible to replace just the Denso-made throttle position sensor itself, I have to replace the entire throttle body unit. Any help would be greatly appreciated. I believe that my vehicle does not have air assisted fuel injection.

Cheers


James Walker

AJ26 engine management does NOT have air assisted fuel injection.

I have only ever replaced the entire throttle assy.(dozens when I worked at the dealer) but getting the position setting correct after replacing just the sensor is probably the 'tricky' part?

Thank you for your reply

The TPS on our early cars (AJ26 engine) is a solid-state Hall-effect device which, in theory, is unlikely to fail. It's worth checking the possible causes associated with those two codes as a starting point:
https://cimg2.ibsrv.net/gimg/www.jag...bd0fdba347.png

Unfortunately, Jaguar chose to use ordinary rotary potentiometers for the other two position sensors which will wear out over time. As far as I know, none of these are available separately (at least, not to we unwashed masses) so your choice is limited to either a replacement TB or finding somewhere that can repair your existing one.

Thanks so much for the advice.

Not entirely true regarding the TPS for the later cars. You can find dozens of different TPS that will physically fit. Many of them Chinese clones from eBay or amazon, as well as parts from other brands such as Toyota. In spite of that, I was never able to find one that worked right. They either did not have the correct programing and/or would not play nice with the Jag's CAN-Bus. In the end, my fix turned out to be as simple as using contact cleaner on the existing unit's harness-end and sensor-end plugs.

Indeed. That is why I stipulated AJ26.

The TPS on later cars is a twin-track rotary potentiometer, and the 'mechanical guard' sensor was not required.

Doh! it's just clicked (I do catch up eventually) that this is a MY97 car.

The ECM in these is notorious for throwing all manner of odd codes and symptoms due to some internal components failing. Take a look at this fairly long thread from Bradstuff:
https://www.jaguarforums.com/forum/x...1/#post1598345

Not exactly the same symptoms, but it was an ECM issue in the end.
It would be well worth pursuing this before condemning the throttle body.

Thanks so much for your advice

Micheal, Do you know when the 97 XK8's switched from hall effect to potentiometer type throttle position sensors? My VIN end in 17818.
Thanks

Hi,
Things changed with the advent of the AJ27 engine, with full authority throttle (fly by wire): MY99 on the XK8.

If your car is throwing odd random codes I would definitely check out the ECM first.

The attached Heritage doc. will show you the VIN breaks.