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Home >> Nissan-Datsun >> 2003 >> Frontier Base, Automatic >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> 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 three-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 warm to operating temperature.
  2. Turn ignition off. Wait 10 seconds.
  3. Start engine. Hold engine speed at 3500-4000 RPM for one minute with no load.
  4. Allow engine to idle for one minute.
  5. On 2.4L models, measure voltage between ground and ECM terminal No. 50 (HO2S1 signal) and No. 56 (HO2S2 signal) by backprobing. See Figure . See Figure or Figure . On 3.3L models, measure voltage between ground and HO2S1 signal circuit at ECM terminal No. 50 (bank 1) or No. 51 (bank 2) by backprobing. Also, measure voltage between ground and HO2S2 signal circuit at ECM terminal No. 56 (bank 1) or No. 57 (bank 2) by backprobing.
  6. On all models, increase engine speed to 2000 RPM, with no load. 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: HO2S1 CIRCUIT SLOW RESPONSE - BANK 1 OR DTC P0153: HO2S1 CIRCUIT SLOW RESPONSE - BANK 2  .
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