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DTC Troubleshooting

DIAGNOSIS PROCEDURE - DTC P0420 CATALYST EFFICIENCY BELOW THRESHOLD (BANK 1)

Step Action Value(s) Yes No
1 Perform an On-Board Diagnostic (OBD) System Check.
Was the check performed?		 - Go to Step 2. Go to "ON-BOARD DIAGNOSTIC (OBD II) SYSTEM CHECK ".
2
  1. Install a scan tool to the Data link Connector (DLC).
  2. Turn the ignition ON.

Are any component Diagnostic Trouble Codes (DTCs) set?		 - Go to applicable DTC TABLE . Go to Step 3.
3
  1. Visually/physically check the following:
  2. Exhaust system for a leak.
  3. Heated Oxygen Sensor (HO2S).

Is a problem found?		 - Go to Step 4. Go to Step 5.
4 Repair the exhaust system as needed.
Is the repair complete?		 - Go to Step 6. -
5 Replace the Three Way Catalytic Converter (TWC).
Is the repair complete?		 - Go to Step 6. -
6
  1. Using the scan tool, clear the Diagnostic Trouble Codes (DTCs).
  2. Start the engine and idle at normal operating temperature.
  3. Operate the vehicle within the Conditions for setting this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic has run and passed?		 - Go to Step 7. Go to Step 2.
7 Check if any additional DTCs are set.
Are any DTCs displayed that have not been diagnosed?		 - Go to applicable DTC TABLE . System OK
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