Warm up the engine for 10 minutes. and making sure that the speed x.x. and the ignition timing is within the normal range, measure the concentration of CO and HC.
If they are out of specification, perform the Air Fuel Ratio Feedback Test as follows.
Turn the ignition key to the ON position (engine not running) and using a jumper, close the SNK and IGN contacts of the diagnostic connector in the car for 2 seconds or more, then remove the jumper.
Warm up the engine, increase the engine speed above approx. 2000 rpm and check that the check engine light comes on 5 times or more within 10 seconds.
Note: When performing a mixture check at idle speed, increase the engine speed to approximately 2000 rpm.