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Home >> Acura >> 1996 >> Integra GS-R, 4D Sedan >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Tests >> DTC P0420 - Catalyst Efficiency Below Threshold
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DTC P0420 - Catalyst Efficiency Below Threshold

NOTE: If any of the following DTCs are displayed at the same time as P0420 service other DTCs first: P0136, P0136, P0141.
  1. Connect and operate scan tester, following manufacturer's instructions. Clear codes. Operate engine at 3000 RPM until cooling fan comes on. Install SCS Service Check Connector Tool.
  2. Test drive vehicle at 40-55 MPH for at least 2 minutes. Decelerate vehicle with throttle completely closed for at least 3 seconds. Reduce speed to 35 MPH and try to hold it there until readiness code comes on. If DTC P0420 is displayed, go to next step. If DTC P0420 is not displayed, fault is intermittent. System okay at this time.
  3. Remove catalytic converter. Shine a flashlight into catalyst inlet while looking into outlet. Replace catalytic converter if signs of deterioration are observed.
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