FixVault
Home › Jeep › 1993 › Grand Cherokee Wagoneer, AWD › Repair and Diagnosis › Engine Performance › System › Engine Controls - Tests W/Codes - 5.2L › No Fault Tests › Test NF-7B - Checking Oxygen (O2) Sensor Switching

Test NF-7B - Checking Oxygen (O2) Sensor Switching

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.
  1. Allow engine to idle. Inspect engine for vacuum leaks. Repair vacuum leaks as necessary. Perform TEST VER-2 . If no vacuum leaks exist, read O2 sensor signal voltage using DRB-II.
  2. If voltage is more than 0.1 volt, go to step 4). If voltage is less than 0.1 volt, turn ignition off. Disconnect O2 sensor connector. Disconnect Powertrain Control Module (PCM) connector. Using DRB-II in ohmmeter mode, check resistance of O2 sensor connector (harness side), signal circuit (Black/Orange wire).
  3. If resistance is less than 5 ohms, repair short to ground in Black/Orange wire. Perform TEST VER-2 . If resistance is more than 5 ohms, replace O2 sensor. Perform TEST VER-2 .
  4. Turn engine off. Replace O2 sensor. Turn ignition on. Using DRB-II, reset adaptive fuel memory. Start engine. Allow engine to reach normal operating temperature.
  5. Using DRB-II, read O2 sensor state. If O2 sensor state is switching, repair is complete. Perform TEST VER-2 . If O2 sensor state is not switching, go to TEST NF-14A .
About FixVault