The yellow light on your OBD-II scan tool indicates there is an emissions system problem. The fault may be either a “Pending” digital trouble code and/or some of the vehicle's emission monitors have not run their diagnostic testing.
Your smog technician is more than likely correct, and your Toyota Celica needs to make "ready" all the emission monitors before it can pass the smog test; and in this specific case, the catalyst monitor. Making the monitors "ready" requires completing a drive cycle specific to your Toyota Celica. The Toyota Celica drive cycle (drive trace) requires may starts and stops, as well as driving at both highway and city speeds. If you feel you might be unable to complete the drive cycle yourself, please seek assistance from a Toyota Repair Center or smog check repair station. Perform the drive cycle at your own risk.
How to Perform Toyota Celica Drive Cycle (Oxygen Sensor)
Begin by: (Make sure you have between 1/4 and 3/4 fuel in the gas tank. The EVAP test will not run while your Toyota Celica has a full tank of gas or the gas tank is near empty). Ensure there are no pending or active trouble codes and that the check engine light is not on. Start the drive cycle from a cold start.
A. Start engine and idle for 3 minutes (until coolant temperature is 1605°f or above). If your engine temp gauge is functioning properly, it should be right around the middle point.
B. Begin driving. Accelerate to 40-55 MPH and maintain speed for seven minutes.
C. Decelerate without touching the brake pedal or clutch to 20 mph, then stop.
D. Idle the engine for one minute.
E. Accelerate to 35-45 MPH and maintain speed for seven minutes.
F. Decelerate to a complete stop and idle engine for one minute.
G. Begin driving. Accelerate the vehicle and maintain steady speed at or above 25 mph for at least 50 seconds. Maintain engine speed above 900 rpm. Stop the vehicle and allow the engine to idle for 40 seconds or more. Repeat this step nine more times.
E. End of Drive Cycle
If readiness status of all monitors do not switch to “ready,” ensure preconditions are met, turn the ignition switch OFF, then repeat steps “A” through “G.”
