The aftermarket TPMS I used is a Schrader AirAware TPMS (Mfg #20257). There are a number of web retailers that carry this kit. One such retailer is Quadratec (
20257 - Schrader® AirAware™ Hard Wired Tire Pressure Monitor System - Quadratec ).
Apparently, the sensors in this kit don't play nice with the electronics of the Smart Car and the idiot light on the dashboard remained lit after the kit and matching sensors were installed.
This problem was resolved by simply blanking out the tire icon on the Smart Car dashboard display. This wasn't a problem for me since I had the dashboard display removed to change out the back-light LED's from the standard amber color to teal green in order to match the back-lighting of the guages I installed. The TPMS display has a warning light and an audible alarm for low tire pressure (in addition to the pressure readout) so blanking out the dashboard idiot light doesn't defeat any safety aspect of the manufacturer's TPMS.
When I researched this unit I couldn't get any information from Smart Car or from Schrader about whether this display unit could "learn" the original equipment sensors (even though the Smart Car uses Schrader TPM sensors). I just replaced the stock tire sensors with the sensors in the kit.
I'll try to get my granddaughter to show me how to download a jpeg file from her digital camera into my computer that I can attach to a post here. I'm clueless about stuff like that.
I forgot to mention in my previous post that I also had an aftermarket cruise control installed. It works great. I use it almost all the time when I'm on the expressway in fifth gear.
In case anyone is wondering, I didn't do any of this work myself. I had all of the guages and the cruise control installed, and all of the dashboard modifications and the under-seat lighting done by a customizing shop here in Cincinnati called Audio Advantage. My total cost for the equipment, installations and dashboard modifications was about $4,000.
Chris