315 mhz or 433 TPMS Sensors
 

Our 2004 Pac is vin # 291,xxx. Rather than remove a wheel sensor how can we tell which frequency does the system read ? Why, you might ask. Our tpms system light came on recently. Tire shop said one was bad and we had it replaced with a Dill 7001HPA 315 mhz. They said to drive it and it will reset. It didn't. Upon checking our records we found the others were older than we first thought so we had the other 3 replaced also. After correct air pressure and driving they still didn't reset plus a message also says "2 tires low pressure" which isn't true by a gauge. Clearly something isn't right. Looking at one of the old sensors the numbers 433 are in the numbers. It was too late to check out at a parts store so we are asking this forum. Thank you. *BW*

I found this chart from Dill( they make aftermarket TPMS sensors), and it looks like there's a good chance you need 433mhz.
If your old ones said 433 on them, that would be the best indicator.
https://cimg3.ibsrv.net/gimg/www.chr...189e78627e.png

Thanks Jeep Guy, agreed. Tomorrow on local AM radio is a call in car repair show. I'll try to get on and ask "How to find out which frequency our car uses", a scan tool might also show it. We'll see how it goes. A friend mentioned that there are dual channel sensors that can be programmed to the correct one by the installer. Dun-no. Thanks. *BW*

Called the live radio car repair show today but didn't quite get the answer I was looking for. Two answers were to go to the Mopar dealer with the car vin info and ask. Go to a good tire shop to have them scan to read which tpms sensors are installed. If I don't come up with a better idea next week I'll go back to the tire shop and plead my case to get it straightened out. May be ez as that. Thanks. *BW*

Success ! Finally ! Went back to the Discount Tire Store I have been dealing with. Had them pull up on their system the TPMS application chart just like Jeep Guy showed and mentioned that they installed 315mhz sensors that won't reset on the cars system. Then I pulled out of my pocket one of the old ones they had replaced and showed them that it was a 433mhz and the car needed that type for the system to work. After a little fidgeting they agreed to replace them all. Less than a hour later I drove away and all was well again. I am so glad I saved the old ones even thought one was bad but the others were replaced because of their age otherwise I would have had over $200 spent and the system still not working. Hang in. *BW*