Replace the HO2S.

Clear DTC with scantool.

Start the engine and warm it up until the radiator fan comes on( more than at least 10 minutes).

Drive at a steady speed between 45-55 mph(72-88 km/h) for 120 sec.

Stop and then maintain idle state.

Check if O2 sensor monitoring readiness is complete.

Does the scan tool show DTC P0153 ?

	▶ Substitute with a known - good ECM and check for proper operation. If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure. note There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by ECM. Before or after testing ECM on the vehicle, use this function to reuse the ECM on the others
	▶ Troubleshooting is finished.