If you have or suspect you may have safety or mission critical embedded systems the Intstitute of Electrical Engineer's extensive advice should be considered essential additional reading. Often embedded systems contain sub-assemblies which are themselves embedded systems, thus compounding the problems of testing and fixing. There is no sure way to determine whether a particular device contains an embedded system or not. Potentially most electrical or electronic devices of any sophistication could contain an embedded system. The best option is to try to obtain a year 2000 compliance statement from the manufactures of all devices that could contain embedded systems.
Many manufacturers now have compliance statements available on the Web.
If a manufacturer's compliance statement is not available, or is not sufficiently reassuring, it is possible to categorise equipment as high or low risk. Equipment which has times or dates appearing on front panel displays, print outs or communication with other equipment is at higher risk of year 2000 problems than equipment without. A system may however suffer from the Year 2000 and other time-related problems even if it does not involve any of these functions or characteristics. The working of the clock may be dependent on a value for the year. Test - this is often not an easy option.