2010 Cadillac CTS Sedan AWD V6-3.6L Page 1404
1. Observe the DTC information with a scan tool. Verify there are no HO2S, fuel system, or misfire DTCs set.
瀚慖f there are any of the DTCs 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, repair as necessary.
3. Verify the following conditions do not exist with the exhaust system:
* Leaks
* Physical damage
* Loose or missing hardware
* Improperly 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) (See: Powertrain Management/Computers and Control Systems/Oxygen
Sensor/Service and Repair)Heated Oxygen Sensor Replacement - Bank 1 Sensor 2 (LLT) (See: Powertrain Management/Computers and
Control Systems/Oxygen Sensor/Service and Repair)
* Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LF1) (See: Powertrain Management/Computers and Control Systems/Oxygen
Sensor/Service and Repair)Heated Oxygen Sensor Replacement - Bank 2 Sensor 2 (LLT) (See: Powertrain Management/Computers and
Control Systems/Oxygen Sensor/Service and Repair)
* Catalytic Converter Replacement - Left Side (LLT) (See: Engine, Cooling and Exhaust/Exhaust System/Catalytic Converter/Service and
Repair/Catalytic Converter Replacement - Left Side)Catalytic Converter Replacement - Left Side (LSA) (See: Engine, Cooling and
Exhaust/Exhaust System/Catalytic Converter/Service and Repair/Catalytic Converter Replacement - Left Side)Catalytic Converter
Replacement - Left Side (LF1) (See: Engine, Cooling and Exhaust/Exhaust System/Catalytic Converter/Service and Repair/Catalytic
Converter Replacement - Left Side)
* Catalytic Converter Replacement - Right Side (LLT) (See: Engine, Cooling and Exhaust/Exhaust System/Catalytic Converter/Service and
Repair/Catalytic Converter Replacement - Right Side)Catalytic Converter Replacement - Right Side (LSA) (See: Engine, Cooling and
Exhaust/Exhaust System/Catalytic Converter/Service and Repair/Catalytic Converter Replacement - Right Side)Catalytic Converter
Replacement - Right Side (LF1) (See: Engine, Cooling and Exhaust/Exhaust System/Catalytic Converter/Service and Repair/Catalytic
Converter Replacement - Right Side)
P0430
DTC P0420 or P0430
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
