Connect GDS to Data Link Connector(DLC).

Ignition "ON"

Monitor "Diagnostic Trouble Codes(DTC)" with GDS.

Fig.1) Diagnostic Trouble Code(DTC) is shown above.

Is DTC status displayed as Present?

	▶ Go to "Monitor GDS Data" procedure.
	▶ Go to "Verification of Vehicle Repair" procedure.

Connect GDS to DLC(Data Link Cable).

Check the "Current Data" about related DTC with GDS.

Fig.1) Engine Starting & Idle before Warm Up

Fig.2) Engine Idle after Warm Up

If the parameter is not similar with shown data, measure related waveforms with GDS.

Fig.1) Engine Idle before Warm Up(HO2S S1, S2 heater)

Fig.2) Engine Idle after Warm Up(HO2S S1, S2 heater)

Are the parameters displayed correctly?

	▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM/PCM’s connector or was repaired and ECM/PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of vehicle Repair" procedure.
	▶ Go to "Terminal and Connector inspection" procedure.