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Home >> Lexus >> 2004 >> SC 430 >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> SFI System - Diagnosis >> DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1), DTC P0430 Catalyst System Efficiency Below Threshold (Bank 2) >> Confirmation Driving Pattern

Confirmation Driving Pattern

Fig 1: Confirmation Driving Pattern
G01447746Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  1. Connect the hand-held tester to the DLC3.
  2. Start the engine and warm it up with all the accessories switched OFF until the engine coolant temperature becomes stable.
  3. Run the engine at 2,500 to 3,000 rpm for about 3 minutes.
  4. Confirming that HO2S band 1 sensor 1 (OXL1) and band 2 sensor 1 (OXR1) have waveforms that are around 0.5 V during feedback to the ECM. Then check the waveform of HO2S bank 1 sensor 2 (OXL2) and bank 2 sensor 2 (OXR2).
    Fig 2: Identifying Waveform Of HO2S
    G01447747Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

The system is malfunctioning when the waveforms of HO2S OXL1 and OXR1 are similar to HO2S OXL2 an OXR2.

In some cases, a malfunction exists but the MIL does not illuminate.