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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 P0139: Bank 1 Heated Oxygen Sensor 2 Circuit - Slow Response Or DTC P0159: Bank 2 Heated Oxygen Sensor 2 Circuit - Slow Response >> 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. Start engine and warm to normal operating temperature. If using CONSULT-II, go to next step. If using generic scan tool, go to step  3.
  2. 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, P0172, P0174 or P0175 is detected and engine is difficult to start, perform diagnosis for DTC P0171, P0172, P0174 or P0175. See DTC P0171 OR DTC P0174  or DTC P0172 OR DTC P0175  . If 1st trip DTC P0171, P0172, P0174 or P0175 is not detected and engine is not difficult to start, go to step  4.
  3. Turn ignition off. Disconnect MAF sensor 5-pin harness connector. See Figure. Start engine and let it idle for at least 5 seconds. Turn ignition off. Reconnect MAF sensor. Using scan tool check that 1st trip DTC P0102 is set. Clear DTCs. Start engine and let it idle for at least 10 minutes. If 1st trip DTC P0171, P0172, P0174 or P0175 is detected and engine is difficult to start, perform diagnosis for DTC P0171, P0172, P0174 or P0175. See DTC P0171 OR DTC P0174  or DTC P0172 OR DTC P0175  . If 1st trip DTC P0171, P0172, P0174 or P0175 is not detected and engine is not difficult to start, go to next step.
  4. Turn ignition off. Disconnect suspect HO2S 2 harness connector. See Figure or Figure . Disconnect ECM 116-pin harness connector. ECM is located behind instrument panel lower cover. See Figure. On bank 1 HO2S 2, check continuity of Orange wire between HO2S 2 harness connector terminal No. 1 and ECM harness connector terminal No. 74. See Figure and Figure . Continuity should exist. On bank 2 HO2S 2, check continuity of Orange/Blue wire between HO2S 2 harness connector terminal No. 1 and ECM harness connector terminal No. 55. Also, check circuits for short to each other or short to voltage. If problem is found, repair as necessary. If no problem is found, go to next step.
  5. Check continuity between engine ground and HO2S 2 harness connector terminal No. 4 (Black wire). Continuity should exist. Also, check circuit for short to voltage. If problem is found, go to next step. If no problem is found, go to step  6.
  6. Reconnect all harness connectors. Start engine. Drive vehicle at a speed of more than 43 MPH for 2 consecutive minutes. Stop vehicle with engine running. If using CONSULT-II, go to next step. If not using CONSULT-II, go to step  8.
  7. Using CONSULT-II, select FUEL INJECTION in ACTIVE TEST mode. Select HO2S 2 (B1)/(B2) as the monitor item. Adjust FUEL INJECTION to +25%. HO2S 2 (B1)/(B2) voltage should be more than 0.62 volt at least once. Adjust FUEL INJECTION to -25%. HO2S 2 (B1)/(B2) voltage should be less than 0.57 volt at least once. If operation is as specified, go to step  10. If operation is not as specified, replace suspect HO2S 2.
  8. Backprobing at ECM, measure voltage between ground and ECM terminal No. 74 (bank 1) or No. 55 (bank 2). While observing voltmeter, snap throttle to 4000 RPM at least 10 times. Voltage should be more than 0.62 volt at least once. If voltage is as specified, go to step  10. If voltage is not as specified, go to next step.
  9. Let engine idle for 10 minutes, then measure voltage again. Or, measure voltage while coasting from 50 MPH in Drive with OD off. Voltage should be less than 0.57 volt at least once. If voltage is as specified, go to next step. If voltage is not as specified, replace suspect HO2S 2.
  10. No problem is indicated at this time. Problem may be intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article.
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