I had a dealer upgrade the TCU in my recently purchased 2013 SL. All seemed to go fine, could connect and everything, except now I intermittently get a TPMS system error. It's not just the low-pressure light (plus I did check all my tires, just in case). The error light will flash for 60 seconds then stay solid. Later, it will turn off completely and everything seems fine, but then sometimes it will come on again. It happens, on average, once per trip, but not every time. I cannot predict when it is going to happen, and can't seem to correlate it with anything in particular. I only had the car for two weeks before I had the TCU upgraded, but it did not happen at all before then. It only started happening after the dealer upgraded the unit. I went back to the dealer and asked about it, and so they went ahead and reset the TPMS system, but that did not fix the problem. They now say it couldn't be related to the TCU upgrade, and if I want a fix, they'll need to charge me to replace the TPMS sensors.