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Home >> Chevrolet >> 2015 >> Spark LS, Automatic CVT Trans >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 1.2L - Diagnostic Information And Procedures >> Diagnostic Information and Procedures >> DTC P0420: Catalyst System Low Efficiency (LFM) >> Circuit/System Verification
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Circuit/System Verification

  1. Ignition On.
  2. Verify there are no other DTCs set.
    • If no other DTCs are set 
  3. Operate the vehicle within the Conditions for Running the DTC.
  4. Verify the scan tool Catalyst Monitor Not At Idle Test Conditions Met parameter changes to Yes.
    • If Yes is not displayed 

      Refer to step  3.

    • If Yes is displayed 
  5. When the conditions are safe, stop and idle the vehicle in gear if equipped with automatic transmission or neutral if equipped with manual transmission.
  6. Verify the Catalyst Monitor Test Result parameter displays Passed when performing the steps listed below:
    1. Apply the service brake.
    2. Monitor the scan tool Catalyst Monitor Test State parameter. When the parameter indicates Active, the Catalyst Monitor Test is running.
    3. Continue to monitor the parameter. When the parameter indicates Inactive, the Catalyst Monitor Test has completed.
      NOTE: When the test has completed, the Catalyst Monitor Test Counter parameter will increment by one and the Catalyst Monitor Test Result parameter will indicate Passed, Failed or No Result.
    • If No Result is displayed 

      Repeat steps  3- 6 until the Test Result parameter indicates Passed or Failed

    • If Failed is displayed 

      Refer to Circuit/System Testing

    • If Passed is displayed 
  7. All OK.
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