Hello all. 1998 SL500 having a problem with the BAS/ESP and ABS lamps coming on at the same time. Funny thing is that they only come on after the car has been operated at highway speeds for about 20 minutes. The lamps reset after turning off the engine and won't come back on during around town driving - only on the interstate after 20 minutes.

Some information on benzworld has indicated a low voltage fault but my system seems to run pretty stable at 13.5v.

Any ideas? A faulty wheel sensor? Vacuum problem?