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Home >> Suzuki >> 2002 >> XL-7 Plus >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0031 Or DTC P0032 >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  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. Turn ignition off. Disconnect Bank 1 HO2S No. 1 4-pin harness connector. Bank 1 HO2S No. 1 is located in left exhaust pipe before catalytic convertor. Measure resistance between Bank 1 HO2S No. 1 pigtail connector terminal No. 3 (Green wire) and No. 4 (Blue wire). See Fig 1. Resistance should be 5.0-6.4 ohms at 68°F (20°C). If resistance is as specified, go to next step. If resistance is not as specified, replace HO2S. After repair, repeat DTC CONFIRMATION TEST .
  3. Disconnect HO2S heater relay. HO2S heater relay is located on left fender well. See Fig 2. Turn ignition on. Measure voltage between ground and HO2S heater relay socket cavity No. 3 (Black/White wire). See Fig 3. Also, measure voltage between ground and HO2S heater relay socket cavity No. 1 (Blue/White wire). If voltage readings at both measurements is 10-14 volts, go to step  5. If voltage readings are not as specified, go to next step.
  4. Check for blown HO2S (15-amp) or IG METER (20-amp) fuses. Fuses are located in underhood fuse and relay box. If fuses are okay, check for open or short to ground in Black/White wire between IG METER fuse and HO2S heater relay. See WIRING DIAGRAMS article. Also, check for open or short to ground in Blue/White wire between HO2S fuse and HO2S heater relay. If problem is found, repair as necessary. After repair, repeat DTC CONFIRMATION TEST .
  5. Turn ignition off. Install HO2S heater relay. Disconnect ECM 30-pin harness connector C51-2. ECM is located under instrument panel, behind glove box. See Figure. Measure voltage between ground and ECM harness connector C51-2 terminal No. 4 (Green wire). See Figure. If voltage reading is 10-14 volts, substitute a known good ECM, and repeat DTC CONFIRMATION TEST . If DTC does not reset, testing is complete. If voltage readings are not as specified, go to next step.
  6. Check for short to ground in Green wire between Bank 1 HO2S No. 1 and ECM. See WIRING DIAGRAMS article. If no problem with wiring is found, replace HO2S heater relay. If problem persists after repairs, substitute a known good ECM, and repeat DTC CONFIRMATION TEST .
Fig 1: Identifying Heated Oxygen Sensor No. 1 Pigtail Connector Terminals
G00163659Courtesy of SUZUKI OF AMERICA CORP.
Fig 2: Locating Heated Oxygen Sensor Heater Relay
G00163687Courtesy of SUZUKI OF AMERICA CORP.
Fig 3: Identifying Heated Oxygen Sensor Heater Socket Cavities
G00163688Courtesy of SUZUKI OF AMERICA CORP.
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