PCM

Gentlemen, I purchased a 2000 seville sls with 70,000 m  on jan 12. Today while driving the message; speed limited to 90 appeared on the dash. What should my course action consist of?

Post code(s) that is stored in car. Dont drive over 90 mph.

Slowroll does that mean driving it under 90 all the time or just when the message appears. 

It means find out why message is coming on, or drive posted speed limit. Car has an Road Sensing Suspension fault occurring  it sets/resets fault code. PCM will limit top speed to 90 mph.

That means that you have a problem with the suspension, if you have the owners manual it tells you there what the problem is when you have that message, I have the same problem and I am trying to find out exactly what the problem is, could possibly needs shocks, or the PCM, if you find out let me know if I find out I will let you know what I do.

It means that you can''t drive anywhere above 90 Psupertar, you can clear it so it won''t show but the governor will kick in at 90, the problem is with the stability control system, probably the shocks, fuse, ground, struts, I am having the same problem, I am just getting started in trying to figure that out, I feel that my car needs shocks, and struts, so after I replace that and if it doesn''t fix it then I will try to figure out what else could be the problem, I will keep you guys posted on it so maybe we can help each other out. 

Definitely time for service. Trouble code(s) that will identify the likely problem have been set. 90 mph is the lowest possible for speed limitation and likely a rather severe problem has been detected in the suspension, traction control or stability system(s). Lacking other messages like "Service Stability System" from the DIC, the problem could be almost anywhere. In my limited experience with a last generation Seville (a 99 STS) I''ve found it best to address problems IMMEDIATELY lest you experience cascading failures and extremely expensive service bills. Not replacing a leaking coolant reservoir cap appears to have led to a failed water pump, leaking radiator and blown head gasket immediately before my purchase. (I knew about the water pump and radiator but the head gasket was a bit of a surpriseat least I paid very little for the car and now have it in top-notch mechanical and cosmetic condition. Be forewarned that the proper shocks and struts are very expensive, but at least they''re simple and inexpensive to install. Age [seems] to be more of a limiting factor of these than mileage. The shocks (rear) in particular seem prone to rust on the lower section that eventually wears the rubber boot surrounding and resulting in a leak of oil. My good mechanic who is quite familiar with these cars said that it''s best to replace both shocks and both struts at the same time.