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Home >> Infiniti >> 2002 >> I35 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0420: Catalyst System Efficiency Below Threshold - Bank 1 Or DTC P0430: Catalyst System Efficiency Below Threshold - Bank 2 >> DTC Confirmation Test (Using Generic Scan Tool)
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DTC Confirmation Test (Using Generic Scan Tool)

NOTE: Use the following test to check overall function of warm-up 3-way catalyst. During this test, 1st trip DTC may not be confirmed.
CAUTION: DO NOT use ECM ground terminals when measuring voltage.
  1. Start engine and drive vehicle at a speed of more than 43 MPH for 2 consecutive minutes. Stop vehicle and leave engine running. Measure voltage between ground and ECM terminal No. 91 (bank 1) or No. 92 (bank 2) by backprobing. See Figure and Figure . Also, measure voltage between ground and ECM terminal No. 88 (bank 1) or No. 90 (bank 2) by backprobing.
  2. Increase engine speed to 2000 RPM. If switching frequency of HO2S2 is less than 75 percent of HO2S1 switching frequency, catalyst is operating properly. If switching frequency of HO2S2 is not less than 75 percent of HO2S1 switching frequency, go to DIAGNOSTIC PROCEDURE  . If HO2S1 does not switch more than 5 times within 10 seconds, diagnose and repair HO2S1. See DTC P0133 OR DTC P0153: HO2S1  .
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