Air/Fuel Mixture: Testing and Inspection

Idle Mixture Check
Before inspection, set vehicles in the following condition:
- Engine coolant temperature: 80 - 95°C (176 - 203°F)
- Lights, electric cooling fan and all accessories: OFF
- Transaxle: Neutral (P range on vehicles with A/T)
2. After turning the ignition switch to OFF, connect the scan tool to the data link connector.
3. Start the engine and run it at 2,500 r/min for 2 minutes.
4. Set the CO, HC tester.
5. Check the CO contents and the HC contents at idle.
Standard value:
CO contents: 0.5% or less
HC contents: 100 ppm or less
6. If the idle speed is outside the standard value, check the following items:
- Diagnostic output
- Closed-loop control (When the closed-loop control is carried out normally, the output signal of the heated oxygen sensor repeats between 0 - 400 mV and 600 - 1,000 mV at idle.)
- Fuel pressure
- Injector
- Ignition coil, spark plug cable, spark plug
- EGR system and the EGR valve leak
- Evaporative emission control system
- Compression pressure

NOTE: Replace the three-way catalyst whenever the CO and HC contents do not remain inside the standard value. (even though the result of the inspection is normal on all items.)