I took my 1994 C220 (107K) out for a long highway ride to my parents house...really the first time since I had the motor mounts/shocks changed last week. Car ran wonderfully.

Start the car in the evening to go back home and the "check engine" light was on continously as soon as I started the car. Shut off and restarted the car...light still came on immediately. Having no other alternative I drove home and the light was on all the time...but the car ran great...so I'm a bit puzzled.

A couple of questions:
(1) If the computer finds a fault, does the light stay on until the computer memory is reset? or by the light staying on means that the fault in happening all the time? (if it goes off, the fault was intermittent)

(2) What commonly causes this condition (oxygen sensor?)...any common problem with the C220?
Would it be OK to drive around for a few days?

(3) I have a friend that is a certified BMW mechanic and he has the tools to read OBDII fault codes...would the BMW tools be applicable? I understand the C220 is OBDII compliant (though not fully)...where is the connector?


Thanks,
Chandra
cbajpai@yahoo.com