LEMON Manuals: Even more car manuals for everyone
Home >> Mazda >> 1997 >> MPV ES, 3.0 3 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Circuit Tests >> DTC P0140 - Rear Oxygen Sensor Activity Not Detected >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

  1. Inspect all applicable harness connectors. Repair as needed. Turn ignition on. Access ECM harness connector. ECM is mounted to passenger floor, behind glove box. Using voltmeter, backprobe applicable ECM harness connector. Measure voltage between ground and terminal No. 2K.
  2. Voltage should be .5-1.0 volt during acceleration, and 0-.5 volt during deceleration. If voltage is within specification, go to step 6). If voltage is not within specification, go to next step.
  3. Turn ignition off. Disconnect rear oxygen sensor harness connector. Using ohmmeter, backprobe ECM harness connector. Check continuity between terminal "B" on rear oxygen sensor harness connector and terminal No. 3O on ECM connector. If continuity does not exist, repair Brown/Yellow wire. If continuity exists, go to next step.
  4. Check continuity between terminal "A" on rear oxygen sensor harness connector and terminal No. 2K on ECM connector. If continuity does not exist, repair Red/Blue wire. If continuity exists, go to next step.
  5. Inspect fuel injectors, mass air flow sensor, engine coolant temperature sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace as needed. Inspect fuel pressure regulator. See appropriate BASIC TESTING article. Replace as needed. Inspect spark plugs and air intake system. Repair or replace as needed. If all items are okay, replace rear oxygen sensor.
  6. Erase DTC. See CLEARING CODES  . If DTC is present, replace ECM. If DTC is not present, intermittent poor harness connection may have caused DTC to originally set.
scientia non olet · About LEMON Manuals