2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1348
Conditions for Clearing the DTC
DTC P0420 and P0430 are Type A DTCs.
Diagnostic Aids
Inspect for the following conditions, which may cause a catalytic converter 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
Reference Information
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning)for scan tool information
Circuit/System Testing
1. Engine idling, observe the DTC information with a scan tool. Verify there are no HO2S or misfire DTCs set.
瀚慖f any of the DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code
Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle) to diagnosis the applicable DTC, before proceeding with this diagnostic
procedure.
2. Verify the following conditions do not exist with the catalytic converter:
* Dents
* A severe discoloration caused by excessive temperatures
* Road damage
* An internal rattle caused by damaged catalyst substrate
* Restrictions
瀚慖f a condition is found, replace the catalytic converter.
3. Verify the following conditions do not exist with the exhaust system:
* Leaks
* Physical damage
* Loose or missing hardware
* Properly torqued HO2S
瀚慖f a condition is found, repair the exhaust system.
4. Verify the following conditions do not exist with the HO2S 2:
* A grounded wiring harness
* Damage
瀚慖f a condition is found, replace the HO2S 2.
5. If no physical condition is detected and the HO2S 2 is as active as the HO2S 1 after operating the engine at 1,500 RPM for 1 minute and then
returning to a stabilized idle, then replace the catalytic converter.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Exhaust Leakage (See: Engine, Cooling and Exhaust/Exhaust System/Testing and Inspection/Exhaust Leakage)
* Restricted Exhaust (See: Engine, Cooling and Exhaust/Exhaust System/Testing and Inspection/Restricted Exhaust)
* Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LF1) ()
