Diagnostic Procedure

1. Turn ignition switch OFF.
2. Loosen and retighten engine ground screws. See Figure .

1. : GO TO 2.

With CONSULT-II 

1. Start engine and warm it up to normal operating temperature.
2. Select SELF-LEARNING CONT in WORK SUPPORT mode with CONSULT-II.
3. Clear the self-learning control coefficient by touching CLEAR. See Figure .
4. Run engine for a least 10 minutes at idle speed.

   Is the 1st trip DTC P0172 or P0175 detected? 

   Is it difficult to start engine? 

Without CONSULT-II 

1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF
3. Disconnect mass air flow sensor harness connector, and restart and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness connector.
5. Make sure DTC P0102 is displayed.
6. Erase the DTC memory. Refer to HOW TO ERASE EMISSION-RELATED DIAGNOSTIC INFORMATION  .
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.

   Is the 1st trip DTC P0172 or P0175 detected? 

   Is it difficult to start engine? 

   Yes or No 

1. Yes: Perform trouble diagnosis for DTC P0172, P0175. Refer to DTC P0172, P0175 FUEL INFECTION SYSTEM FUNCTION  .
2. No: GO TO 3.

1. Turn ignition switch OFF.
2. Disconnect corresponding heated oxygen sensor 2 harness connector. See Figure .
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminal and HO2S2 terminal as follows.

   Refer to Wiring Diagram.

   Fig 1: Displaying ECM & HO2S2 Terminal Continuity

   Courtesy of NISSAN MOTOR CO., U.S.A.

   Continuity should exist. 

5. Check harness continuity between ECM terminal or HO2S2 terminal and ground as follows.

   Refer to Wiring Diagram.

   Fig 2: Displaying ECM, HO2S2 Terminal & Ground Continuity

   Courtesy of NISSAN MOTOR CO., U.S.A.

   Continuity should not exist. 

6. Also check harness for short to power.

   OK or NG 

1. OK: GO TO 4.
2. NG: Repair open circuit or short to ground or short to power in harness or connectors.

1. Check harness continuity between HO2S2 terminal 4 and engine ground.

   Refer to Wiring Diagram.

   Continuity should exist. 

2. Also check harness for short to power.

OK or NG 

1. OK (With CONSULT-II): GO TO  6 .
2. OK (Without CONSULT-II): GO TO  7 .
3. NG: GO TO 5.

Check the following.

• Joint connectors-18
• Harness for open or short between heated oxygen sensor 2 and ground

1. : Repair open circuit or short to power in harness or connectors.

With CONSULT-II 

1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch ON and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least one minute under no load.
4. Let engine idle for one minute.
5. Select FUEL INJECTION in ACTIVE TEST mode, and select HO2S2 (B1)/(B2) as the monitor item with CONSULT-II.
6. Check HO2S2 (B1)/(B2) at idle speed when adjusting FUEL INJECTION to +/-25%. See Figure .

   HO2S2 (B1)/(B2) should be above 0.63V at least once when the FUEL INJECTION is +25%. 

   HO2S2 (B1)/(B2) should be below 0.48V at least once when the FUEL INJECTION is -25%. 

   CAUTION:

   • Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a hard surface such as a concrete floor; use a new one.
   • Before installing new oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.

   OK or NG 

1. OK: GO TO  9 .
2. NG: Replace malfunctioning heated oxygen sensor 2.

Without CONSULT-II 

1. Start engine and warm it up to the normal operating temperature.
2. Turn ignition switch ON and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least one minute under no load.
4. Let engine idle for one minute.
5. Set voltmeter probes between ECM terminal 88 (HO2S2 bank 1 signal) or 90 (HO2S2 bank 2 signal) and engine ground.
6. Check the voltage when revving up to 4,000 rpm under no load at least 10 times.

   (Depress and release accelerator pedal as soon as possible.)

   Fig 3: Checking Voltage When Revving Up To 4,000 Rpm Under No Load

   Courtesy of NISSAN MOTOR CO., U.S.A.

   The voltage should be above 0.63V at least once during this procedure. 

   OK or NG 

1. OK: GO TO  9 .
2. NG: GO TO 8.

Without CONSULT-II 

Idle vehicle for 10 minutes, then check voltage between the same terminals as in Test No. 7; or check voltage when coasting from 80 km/h (50 MPH) in D position with OD OFF.

The voltage should go below 0.48V at least once during this procedure. 

OK or NG 

1. OK: GO TO 9.
2. NG: Replace malfunctioning heated oxygen sensor 2.

Refer to TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT  .

1. : INSPECTION END