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DTC P0133 - PRIMARY HO2S-1 SENSOR SLOW RESPONSE Isuzu Oasis I

Testing & Diagnostics 1 illustration ~655 words

Note. If DTCs P0131, P0132 and/or P0135 exist with P0133, trouble shoot DTC P0133 last.

  1. Perform PCM reset procedure. See «TESTS W/CODES - INTRODUCTION»(ref-16345) article. Connect OBD-II scan tool. Start engine and run at 3000 RPM with no loads and transmission in Park or Neutral until radiator fan comes on. Allow engine to idle. Connect SCS Service Connector (07PAZ-0010100). Test drive vehicle at 55 MPH, with transmission in D4 position (A/T), until readiness code comes on.
  2. If DTC P0133 is not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at HO2S-1 and PCM connectors. See WIRING DIAGRAMS article. Repair as necessary. If DTC P0133 is indicated, replace HO2S-1.

Scheme 28

Scheme 28: DTC P0135 OR DTC P0141 - HO2S SENSOR HEATER CIRCUIT MALFUNCTION
Scheme 28: DTC P0135 OR DTC P0141 - HO2S SENSOR HEATER CIRCUIT MALFUNCTION
  1. Perform PCM reset procedure. See «TESTS W/CODES - INTRODUCTION»(ref-16345) article. Start engine. If DTC P0135 or P0141 is indicated, go to next step. If DTC P0135 or P0141 is not indicated, problem is intermittent. System is okay at this time. Check for poor connections or loose wires at suspect HO2S sensor and PCM connectors. See WIRING DIAGRAMS article. Repair as necessary.
  2. Turn ignition off. Disconnect suspect HO2S 4-pin connector. Measure sensor resistance between suspect HO2S 4-pin connector terminals No. 3 (Black wire) and No. 4 (Black wire). see scheme 8or (Scheme 28). If resistance is 10-40 ohms, go to next step. If resistance is not 10-40 ohms, replace suspect HO2S.
  3. Check for continuity between ground and suspect HO2S terminals No. 3 (Black wire) and No. 4 (Black wire), individually. see scheme 8or (Scheme 28). If continuity exists, replace suspect HO2S. If continuity does not exist, go to next step.
  4. Turn ignition on. Measure voltage between suspect HO2S harness connector terminals No. 3 (Black/Yellow wire on HO2S-1; Orange/Black wire on HO2S-2) and No. 4 (Black/White wire on HO2S-1; Black/Yellow wire on HO2S-2). If battery voltage exists, go to next step. If battery voltage does not exist, go to step 6).
  5. Turn ignition off. If checking HO2S-1 (DTC P0135), disconnect PCM 31-pin connector "C". Check for continuity between ground and PCM 31-pin connector "C" terminal C1 (Black/White wire). see scheme 3 See WIRING DIAGRAMS article. If checking HO2S-2 (DTC P0141), disconnect PCM 32-pin connector "A". Check for continuity between ground and PCM 32-pin connector "A" terminal A8 (Orange/Black wire). see scheme 1 See WIRING DIAGRAMS article. If continuity exists, repair short in Black/White wire (DTC P0135) or Orange/Black wire (DTC P0141) between suspect HO2S and PCM. If continuity does not exist, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.
  6. If checking HO2S-1 (DTC P0135), measure voltage between ground and HO2S-1 harness connector terminal No. 3 (Black/Yellow wire). see scheme 8 If checking HO2S-2 (DTC P0141), measure voltage between ground and HO2S-2 harness connector terminal No. 4 (Black/Yellow wire). (Scheme 28) If battery voltage exists, go to next step. If battery voltage does not exist, repair open or short in Black/Yellow wire between suspect HO2S connector and No. 4 ECU/PCM CRUISE CONTROL (15-amp) fuse. See WIRING DIAGRAMS article.
  7. Turn ignition off. Reconnect HO2S 4-pin connector. If checking HO2S-1 (DTC P0135), disconnect PCM 31-pin connector "C". Turn ignition on. Using backprobe kit, measure voltage between PCM 25-pin connector "B" terminal B2 (Black wire) and PCM 31-pin connector "C" terminal C1 (Black/White wire). see scheme 2and see scheme 3. See WIRING DIAGRAMS article. If checking HO2S-2 (DTC P0141), disconnect PCM 32-pin connector "A". Using backprobe kit, measure voltage between PCM 25-pin connector "B" terminal B2 (Black wire) and PCM 32-pin connector "A" terminal A8 (Orange/Black wire). see scheme 1and see scheme 2. See WIRING DIAGRAMS article. If voltage is 0.1 volt or less, repair open in Black/White wire (DTC P0135) or Orange/Black wire (DTC P141) between suspect HO2S and PCM. See WIRING DIAGRAMS article. If voltage is more than 0.1 volt, substitute a known-good PCM and recheck. If symptom or indication goes away, replace original PCM.

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