What year is the car?
When does the light come on? it should come on when the ignition is switched on then go out when the engine starts. If it comes on after a couple of miles , then resets when you restart, it could be an underinflated tyre or odd sized tyres.
How long have you had the car and how long has this been going on for?
'08 Chrysler 300CRD (MB OM 642 engine)
'95 E220 estate
'89 230TE (R.I.P.)