I noticed it the day after I got Traveler Back from its service ‘A’.  When I shut down the car after a brief drive, the central speedometer display flashed a warning message that the tire pressure was low.  So I took my gauge out of the glove compartment and checked and it wasn’t and I wrote it off to a random spurious signal that must have happened when I turned the car off.  Some voltage spike that sent a signal down the wire that the car’s central computer misinterpreted.  But the next day it was back.  And the next.  And then this morning, while I was driving to the hardware store the warning flashed red on the display just as I was pulling out onto the highway.  I pulled over and checked and everything was fine.  None of the tires were low at all.

The problem with the legendary Mercedes reliability, is that from the mid-1990s to about 2005 it was anything but.  The company had a reliability problem…a bad one…mostly with the electrical systems…and owners and fans of the brand were getting royally pissed off.  But the company fessed up to it, and promised to make changes and do better, and from everything I’ve heard, the cars built from 2005 onward are much, Much better.  But I just know that every time something like this happens I’m going to stress that it’s a defect.

I’m assuming for now that something was done in the shop during the ‘A’ service that made the tire pressure monitoring system forget its baseline values and so it started complaining that the tire pressure wasn’t right. You’re supposed to reset the tire pressure warning system every time you adjust the tire pressure.  There’s a routine you perform…you let the tires cool down for at least three hours after driving, then check and adjust the pressure as necessary, then you tell the system to accept the current values as the baseline.  This morning I took my air compressor out to the car and, as a matter of fact, one tire was about 2 psi low.  But I doubt that’s low enough to set off the warning system.  In any case, I set all the tires to their correct pressure and then reset the warning system and then took Traveler out for a long drive and so far the warning hasn’t reappeared. If it doesn’t again then I think I can safely assume that it was a result of something the shop did during the ‘A’ service.