DTC Troubleshooting: P0420 (67) (K20Z: M/T)

DTC Troubleshooting: P0420 (67)

DTC P0420:  Catalyst System Efficiency Below Threshold


NOTE:

1.Turn the ignition switch ON (II).

2.Clear the DTC with the HDS.

3.Start the engine. Hold the engine speed at 3,000 rpm (min-1) without load (in Park or neutral) until the radiator fan comes on, then let it idle.

4.Test-drive under these conditions:
  • ECT SENSOR 1 above 70 °C (158 °F)
  • A/T in D position (M/T in 5th gear)
  • Vehicle speed between 72-120 km/h (45- 75 mph) for 5 minutes or more with cruise control set
  • Maintain the vehicle speed at 88 km/h (55 mph) for 5 minutes or more with cruise control set

5.Monitor the OBD STATUS for DTC P0420 in the DTCs MENU with the HDS.

Does the screen indicate EXECUTING?


YES - Go to 6.


NO - Go to 4 and recheck.


6.Continue test driving until a result comes on.

7.Monitor the OBD STATUS for DTC P0420 in the DTCs MENU with the HDS.

Does the screen indicate FAILED?


YES - Go to 8.


NO - If the screen indicates PASSED, intermittent failure, system is OK at this time. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to 4 and recheck.


8.Turn the ignition switch OFF.

9.Replace the TWC.

10.Turn the ignition switch ON (II).

11.Reset the ECM/PCM with the HDS.

12.Do the ECM/PCM idle learn procedure.

13.Start the engine. Hold the engine speed at 3,000 rpm (min-1) without load (in Park or neutral) until the radiator fan comes on, then let it idle.

14.Test-drive for about 10 minutes, varying the vehicle speed.

15.Check the CATA MON TEMP in the DATA LIST with the HDS.

Is the temperature OK?


YES - Go to 16.


NO - Go to 13 and recheck.


16.Test-drive under these conditions:
  • ECT SENSOR 1 above 70 °C (158 °F)
  • A/T in D position (M/T in 5th gear)
  • Vehicle speed at 88 km/h (55 mph) for 5 minutes or more with cruise control set

17.Monitor the OBD STATUS for DTC P0420 in the DTCs MENU with the HDS.

Does the screen indicate EXECUTING?


YES - Go to 18.


NO - Go to 16 and recheck.


18.Continue test-driving until a result comes on.

19.Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - Go to the indicated DTC's troubleshooting.n


NO - Go to 20.


20.Monitor the OBD STATUS for DTC P0420 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?


YES - Troubleshooting is complete.n


NO - If the screen indicates FAILED, check the fuel quality. If the screen indicates EXECUTING, keep driving until a result comes on. If the screen indicates OUT OF CONDITION, go to 13 and recheck.