What's the difference between 4X 43 15K 866 AG and 4X 43 15K 866 AB or AC, I need to replace mine with AG suffix but can only find ones with AB or AC suffixes.

 

Les Royal, The AG/AB/AC are all revision codes. If Jaguar modifies the part for any reason, they go to the next letter combo, (AA, then AB, then AC, .....). Now, these changes can be something as simple as changing the diameter of the barrel at some point on the sensor to a different value. It could be a complete revamp of the part and how it works. I have never seen a chart for a part that says what each revision is. Because the parking sensors are fairly generic and get used on many vehicles (for reference the 15K866 is the part number and the 4x43 is telling me that it came out of a Jaguar X-Type that was made after March 2004). the changes may not even be related to the X-Type. So, go ahead and by the AB or AC sensors and you should be fine.

One word of caution. When removing the old sensor, there are 2 tabs holding it in place, take a screw driver or something similar and hold the tabs back as you push on the center of the sensor and push it into the bumper. If you twist the sensor, you risk breaking the sensor. TRUST ME!!!!!! Same thing with installing, Push on the center of the sensor as you are installing it once you have the retaining clips lined up. Straight in, straight out.

 

Thanks for the info, I typed sensor when I should have said module. Does your explanation obviously still hold true for the module in the wheel well? My X type has succumbed to the water in the well problem, which I see on this site is apparently exceedingly common.

 

Lew Royal. Yes, the same is true. The only thing that you have to be careful with on the X-Type is that the early cars only had rear parking assist and the later cars had front and rear parking assist. So, what module you get needs to have what your car is equipped with.