If considering the purchase of new wheel sensors, I recommend any that are pre-programmed. These can be bought from Schrader, Autel, Redi-Sensor, etc. Best option is to clone the existing sensors (if they still are operable) so the TPMS module (located under the interior light module mounted in the headliner) will be able to recognize the replacement wheel sensors since they have the same IDs as the OEM sensors. (Note: Gotta make sure the tire shop mounts the cloned wheel sensor & tire in the same position as the OEM sensor & tire.) Otherwise, you'll need to be able to have someone with a DRB3 Emulator perform a 're-learn' setup to load new wheel sensor IDs into the TPMS Module. Several of us have this software w/Micropod device & can perform this 're-learn' setup for you - just ask around. Another option is to find a dealer that still has the OEM DRB tooling but you'll pay out the 'ying-yang' to have them do this. Most independent tire shops won't be able to perform the 're-learn' setup since they don't have the software. (Note: I've always wondered why an independent M-B shop wouldn't invest in the DRB3 Emulator w/Micropod so they could handle replacing TPMS wheel sensors on a Crossfire & execute the 're-learn' setup. It's only several hundred $s for the whole shooting match.)