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Home >> Toyota >> 2005 >> Matrix Base, 4WD >> Repair and Diagnosis (Single Page) >> Engine Performance >> Engine Control System (SFI) (1ZZ-FE(4WD)) - Diagnostics >> SFI System (1ZZ-FE (4WD)) >> DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1) >> Confirmation Driving Pattern
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Confirmation Driving Pattern

Fig 1: Identifying Confirmation Driving Pattern
G02662220Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. If using a hand-held tester: Connect the hand-held tester to the DLC3.
  2. If not using a hand-held tester: Connect oscilloscope tester probes to terminals OX1A (front Heated Oxygen [HO2] sensor: Sensor 1), OX1B (rear HO2 sensor: Sensor 2) and E1 of the ECM connector.
  3. Start the engine.
  4. Warm up the engine with all the accessories switched OFF until the engine coolant temperature stabilizes.
  5. Run the engine at an engine speed of between 2,500 rpm and 3,000 rpm for approximately 3 minutes.
  6. Check that the waveform of the OX1B (rear HO2 sensor) signal.

HINT:

If there is still a malfunction in the system, the waveform of OX1B may become similar to the OX1A waveform shown in the diagram on the left.

Fig 2: Identifying Front HO2 Sensor Signal Waveform
G02662221Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002