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Home >> Suzuki >> 2003 >> XL-7 Base, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 18 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0420: Bank 1 Catalyst System - Low Efficiency >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

WARNING: This page is about a different car, the 2002 Suzuki XL-7. However, it is still accessible from the selected car via links, so may be relevant.
  1. If engine system check has been performed, go to next step. If engine system check has not been performed, go to A4: ENGINE SYSTEM CHECK  under SYSTEM TESTS.
  2. Inspect exhaust system for damage or leaks. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If no problem is found with exhaust system, go to next step.
  3. Drive vehicle for at least 2 minutes at 35 MPH or more. Observe Bank 1 HO2S No. 2 parameter on scan tool display while revving engine. If scan tool displays continuously varying voltage above and below .3 volts, replace catalyst. After repair, repeat DTC CONFIRMATION TEST . If voltage is not as specified, go to next step.
  4. Check for open or short in Red/Black wire between Bank 1 HO2S No. 2 and ECM. See WIRING DIAGRAMS article. Also, check for open or short in Gray/Yellow wire between Bank 1 HO2S No. 2 and ECM. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If no problem is found, go to next step.
  5. Disconnect Bank 1 HO2S No. 2 4-pin harness connector. Bank 1 HO2S No. 2 is located in left exhaust pipe after catalytic convertor. Disconnect ECM 26-pin harness connector C51-3. ECM is located under instrument panel, behind glove box. See Figure. Check for poor terminal contact at Bank 1 HO2S No. 2 harness connector and ECM harness connector C51-3. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST . If no problem with wiring is found, replace Bank 1 HO2S No. 2. After repair, repeat DTC CONFIRMATION TEST .
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