general problems of the 1998 Hyundai Sonata

Caller stated: brought car in for inspection. When the car was hooked up the monitor status with the onboard computer red not ready on everything. Mechanic told consumer that he had to drive the car on a highway for 20 minutes, then drop down to 15 mph for 5 minutes, and then repeat, followed by a rest period of 5 hours. All to get the computer to give out the correct reading.