Constant loss of tire air pressure

My wife has a 2005 Liberty Limited that's had problems with tire pressure from day one. Even when we test drove it a year ago the dash indicator gave us a low pressure warning for the spare. In the last year she's had it back at both the Jeep dealership and Goodyear numerous times, always being told they can't find a problem. This time I suggested she make the dealer replace the valve stems along with the sensor on the end of them. They agreed to do this but when the parts group tries to order them they find Jeep has over 600 of the stems and sensors on backorder. I work in Technical Service for a large company and I know when an item that common is on backorder then it probably means there's a manufacturing defect being worked. I'm sure Jeep has an outside vendor providing these but they should have at least sent a notice to their dealerships about this problem.

Part Number # 68001696aa
qty; 4. Location; PERKINS EASTSIDE CRESTWOOD KY USA.
502-241-7191
Updated: February 18, 2006 800-876-6620

Dealer Locator info. 861 pieces in Dealer inventory throughout Nation.
Pipeline info 66 outstanding orders for 123 pieces, 2873 pieces in transit to dealers .
although the part is on back order if the Dealer orders it correctly it shouldnt take more than 5-7 days to have that part in hand. also if another dealer has stock they should ship it unless it is a spec order for a customer.
the Part is not a very common part but there have been issues with customers complaining of an irritating light coming on. it is however not a safety issue and is not a drivability issue so the priority of the situation is not as high as a customer with a vehicle that wont run or has a safety concern.
goodluck

Thanks for that info. It may not be a safety issue but it is a pain in the butt. Every morning that the temperature is below freezing, I have to put air in my wife's tires. At 5:00am and 10 degrees, that's what I call a hazard. I'm going to print your reply and make my local dealer's service group read it. Today I'm not leaving until it's fixed.