Warm up the engine for 10 minutes and, after making sure that the idle speed and ignition timing are within normal limits, measure the concentration of CO and HC.
If they are different from the norm, perform a feedback test of the air-fuel ratio adjustment as follows.
Turn the ignition key to the ON position (the engine is not working) and using a jumper, close the contacts of the diagnostic connector SNK and IGN in the vehicle's interior for 2 seconds or more, then remove the jumper.
Warm up the engine, increase the engine speed above approximately 2000 rpm and check that the check engine light comes on 5 times or more within 10 seconds.
Note: When checking the air-fuel ratio at idle speed, increase the engine speed to approximately 2000 rpm.