Cruze

DTC P0420

Note: A new converter with less than 160 km (100 miles) on it may set DTC P0420 00 due to out-gassing of the internal matting. Operating the vehicle at motorway speeds for approximately 1 h may correct the condition.

A 3-way catalyst controls emissions by converting hydrocarbons and carbon monoxide (CO) into carbon dioxide (CO2), and oxides of nitrogen (NOX) into nitrogen. The 3-way catalyst also stores oxygen. When the listed driving conditions are met, the Catalyst System Efficiency test will run. The engine control module (ECM) monitors this oxygen storage capacity by comparing the pre-catalyst with the post-catalyst oxygen sensor signals while adding and subtracting fuel during specific driving conditions. The ECM compares the pre-catalyst with the post-catalyst oxygen sensor signals to determine if the oxygen storage capacity of the catalyst is degraded.

DTC P0420 00 is a Type A DTC.

DTC P0420 00 is a Type A DTC.

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Caution: Refer to Three-Way Catalytic Converter Damage Caution in the Preface section.

Caution: Refer to Heated Oxygen Sensor Resistance Learn Reset Caution in the Preface section.

Note: A new converter with less than 160 km (100 miles) on it may set DTC P0420 00 due to out-gassing of the internal matting. Operating the vehicle at motorway speeds for approximately 1 h may correct the condition.

1. If any other DTCs are set, perform those diagnostics first.
2. Inspect for the following conditions which may cause a catalyst to degrade:

•	An engine misfire

•	High engine oil or high coolant consumption

•	Retarded spark timing

•	A weak or poor spark

•	A lean fuel mixture

•	A rich fuel mixture

•	A damaged oxygen sensor or wiring harness

•	The catalyst test may abort if the vehicle falls outside the conditions for running the DTC.

•	A catalyst may be temporarily degraded if a fuel with high sulphur content has been used. Drive the vehicle at highway speeds for 10 minutes and retest the converter.

3. Operate the vehicle within the conditions for running the DTC.

⇒	If the DTC fails this key cycle, continue with this procedure.

4. Inspect the catalyst for the following conditions:

•

Dents

•	A discolouration of the catalyst caused by higher temperatures as the customer may desire

•	Road damage

•	An internal rattle caused by damaged catalyst substrate

•	Restrictions

⇒	If a condition is found, replace the catalyst.

5. Inspect the exhaust system for the following conditions:

•

Leaks

•	Physical damage

•	Loose or missing hardware

•	Properly torqued B52A Heated Oxygen Sensor 1

•	Restrictions

⇒	If a condition is found, repair the exhaust system.

6. Inspect the B52B Heated Oxygen Sensor 2 for the following conditions:

•	A grounded wiring harness

•

Damage

⇒	If a condition is found, replace the B52B Heated Oxygen Sensor 2.

⇒	If no physical condition is detected, replace the catalyst.

Note: A new converter with less than 160 km (100 miles) on it may set DTC P0420 00 due to out-gassing of the internal matting. Operating the vehicle at motorway speeds for approximately 1 h may correct the condition.

1. Clear the DTCs.
2. Operate the vehicle within the Conditions for Running and Setting for at least 10 minutes
3. Stop the vehicle.
4. Engine OFF, allow the ECM to power down.
5. Operate the vehicle within the Conditions for Running and Setting for at least 10 min. DTC P0420 00 should run and pass.