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Home >> Nissan-Datsun >> 1993 >> Sentra SE-R, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 2.0L >> Diagnostic Trouble Code (DTC) Tests >> DTC 33: Oxygen Sensor
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DTC 33: Oxygen Sensor

  1. Check System Function  - During self-diagnostic test Mode II, Red LED on ECM and MIL on instrument panel should blink 5 times within 10 seconds when engine speed is about 2000 RPM. If lights are as specified, testing is complete. If lights are not as specified, go to next step.
  2. Check Input Signal Circuit  - Turn ignition off. Disconnect ECM. See Figure . Disconnect oxygen sensor harness connector. See Fig 1 . Check continuity between oxygen sensor wiring harness connector terminal "b" and ECM connector terminal No. 19. See Figure and Fig 2 . If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.
  3. Check Voltage  - Turn ignition off. Reconnect oxygen sensor and ECM wiring harness connector. Start engine. Measure voltage between ECM terminal No. 19 and ground. See Figure and Fig 3 . Raise engine speed to about 2000 RPM. At 2000 RPM, voltage should fluctuate. If voltage remains fixed at 0.3 volt, replace oxygen sensor and perform FINAL CHECK  in this article. If voltage fluctuates, repair ECM pin terminals and/or connector terminals.
  4. Check Voltage Using Consult Tester (J-38465)  - Turn ignition off. Connect Consult tester, oxygen sensor harness connector and ECM harness connector. Select DATA MONITOR mode with Consult tester. Raise engine speed to about 2000 RPM. Touch RECORD on Consult tester. Check O2 SEN voltage. If voltage remains fixed at 0.3 volts, replace oxygen sensor and perform FINAL CHECK  in this article. If voltage fluctuates, repair ECM pin terminals and/or connector terminals.
Fig 1: Locating Oxygen Sensor Harness Connector
G93C80939Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 2: DTC 33, Checking Input Signal Circuit
G93F80940Courtesy of NISSAN MOTOR CO., U.S.A.
Fig 3: DTC 33, Checking Voltage
G93G80941Courtesy of NISSAN MOTOR CO., U.S.A.