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Home >> Infiniti >> 2010 >> QX56 AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - DTCS U1000 To P0308 >> DTC P0139, P0159: Ho2S2 >> Overall Function Check
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Overall Function Check

Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st trip DTC might not be confirmed.

WITH GST

  1. Start engine and warm it up to the normal operating temperature.
  2. Turn ignition switch OFF and wait at least 10 seconds.
  3. Start engine and keep the engine speed between 3, 500 and 4, 000 RPM for at least 1 minute under no load.
  4. Let engine idle for 1 minute.
  5. Set voltmeter probes between ECM terminal 55 [HO2S2 (B1) signal] or 74 [HO2S2 (B2) signal] and 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.)

    A change of voltage should be more than 0.12V for 1 second during this procedure. 

    If the voltage can be confirmed in step   6 , step 7 is not necessary. 

  7. Keep vehicle at idling for 10 minutes, then check the voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D position.

    A change of voltage should be more than 0.12V for 1 second during this procedure. 

    Fig 1: Checking Voltage Between ECM Connector Terminals 55 Or 74 And Ground
    G06315557Courtesy of NISSAN MOTOR CO., U.S.A.
  8. If NG, go to "DIAGNOSIS PROCEDURE ".