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DTC P0138 - SECONDARY HO2S-2 SENSOR HIGH VOLTAGE Isuzu Oasis I

Testing & Diagnostics ~252 words
  1. Perform PCM reset procedure. See «TESTS W/CODES - INTRODUCTION»(ref-16345) article. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Using OBD-II scan tool, check HO2S-2 output voltage with engine at 3000 RPM. If voltage stays at 0.6 volt or more, go to next step. If voltage does not stay at 0.6 volt or more, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at PCM and HO2S-2 connectors. See WIRING DIAGRAMS article. Repair as necessary.
  2. Turn ignition off. Disconnect HO2S-2, 4-pin connector. Connect a fused jumper wire between HO2S-2 harness connector terminals No. 1 (Green/Black wire) and No. 2 (White/Red wire). (Схема №9) Turn ignition on. Using OBD-II scan tool, check HO2S-2 output voltage. If output voltage is 0.6 volt or more, go to next step. If output voltage is not 0.6 volt or more, replace HO2S-2.
  3. Turn ignition off. Using backprobe kit, connect a fused jumper wire between PCM 32-pin connector "A" terminal A23 (White/Red wire) and PCM 31-pin connector "C" terminal C18 (Green/Black wire). (Схема №1)and (Схема №3). Turn ignition on. Using OBD-II scan tool, check HO2S-2 output voltage. If output voltage is less than 0.6 volt, repair open in White/Red wire between PCM and HO2S-2. See WIRING DIAGRAMS article. If output voltage is 0.6 volt or more, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.

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