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Home >> Nissan-Datsun >> 2003 >> Sentra Limited >> Repair and Diagnosis >> External Pages >> Different car >> Section 112 (Engine Controls Self-Diagnostics - Pathfinder) >> Diagnostic Tests >> DTC P1143: Bank 1 Heated Oxygen Sensor 1 - Lean Shift Monitoring Or DTC P1163: Bank 2 Heated Oxygen Sensor 1 - Lean Shift Monitoring >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Nissan Pathfinder. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition off. Loosen and retighten 2 engine ground bolts. See Figure. Go to next step.
  2. Loosen and retighten suspect HO2S 1 to 30-44 ft. lbs. (40-60 N.m). See Figure or Figure . If using CONSULT-II, go to next step. If not using CONSULT-II, go to step  4.
  3. Start engine and warm to normal operating temperature. Select SELF-LEARNING CONT in WORK SUPPORT mode with CONSULT-II. Clear self-learning control coefficient by pressing CLEAR. Let engine idle for at least 10 minutes. If 1st trip DTC P0171 or P0174 is detected and engine is difficult to start, perform diagnosis for DTC P0171 or P0174. See DTC P0171 OR P0174 . If 1st trip DTC P0171 or P0174 is not detected and engine is not difficult to start, go to step  5.
  4. Turn ignition off. Disconnect MAF sensor harness connector. See Figure. Start engine and let it idle for at least 5 seconds. Turn ignition off. Reconnect MAF sensor. Ensure DTC P0102 is set. Clear DTCs. Start engine and let it idle for at least 10 minutes. If 1st trip DTC P0171 or P0174 is detected and engine is difficult to start, perform diagnosis for DTC P0171 or P0174. See DTC P0171 OR P0174 . If 1st trip DTC P0171 or P0174 is not detected and engine is not difficult to start, go to next step.
  5. Disconnect suspect HO2S 1 4-pin harness connector. Measure resistance between suspect HO2S 1 specified pigtail terminals. See CHECKING HO2S 1 RESISTANCE table. See Figure or Figure . If resistance or continuity is as specified and CONSULT-II is available, go to next step. If resistance or continuity is as specified and CONSULT-II is not available, go to step  7. If resistance or continuity is not as specified, go to step  8.
    CHECKING HO2S 1 RESISTANCE

    Measure Between Terminals No. Specification (Ohms)
    2 & 3 2.3-4.3 @ 77°F (25°C)
    1 & 2, 3 Or 4 No Continuity
    4 & 1, 2 Or 3 No Continuity
  6. Connect any disconnected harness connectors. Start engine and warm to normal operating temperature. Select MANU TRIG, and adjust TRIGGER POINT to 100% in DATA MONITOR mode with CONSULT-II. Select HO2S 1 MNTR (B1)/(B2) and HO2S 1 MNTR (B1)/(B2). Hold engine speed at 2000 RPM. Press RECORD. The following should occur:
    • HO2S 1 MNTR (B1)/(B2) changes from RICH to LEAN to RICH 5 times in 10 seconds.
    • HO2S 1 (B1)/(B2) voltage goes above 0.6V at least once.
    • HO2S 1 (B1)/(B2) voltage goes below 0.3V at least once.
    • HO2S 1 (B1)/(B2) voltage never exceeds 1.0V.
    If operation is as specified, go to step  9. If operation is not as specified, go to step  8.
  7. CAUTION: DO NOT use ECM ground terminals when measuring voltage.
  8. Connect any disconnected harness connectors. Start engine and warm to normal operating temperature. Backprobing at ECM, measure voltage between ground and ECM terminal No. 35 (bank 1) or No. 16 (bank 2). See Figure and Figure . Increase engine speed to 2000 RPM. The following should occur:
    • Voltage should cycle from less than 0.3 volt to more than 0.6 volt and back more than 5 times within 10 seconds.
    • Maximum voltage should be more than 0.6 volt at least once.
    • Minimum voltage should be less than 0.3 volt at least once.
    • Voltage should never exceed one volt.
    If operation is not as specified, go to next step. If operation is as specified, go to step  9.
  9. Replace suspect HO2S 1. After repair, repeat appropriate DTC Confirmation Test.
  10. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.