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Home >> Alfa Romeo >> 2019 >> Giulia Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> 2.0L - DTCS P2AE2-00 To U148C-00 >> DTC Troubleshooting >> P2B89-00-Intake Air O2 Sensor Circuit Low Voltage >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    NOTE:

    This DTC sets to indicate a general Intake O2 Sensor system circuit or component failure. The PCM runs secondary tests to pinpoint which circuit has the failure. It is important to diagnose any correlating DTCs relating to this fault first. If there are no other DTCs present, the most likely cause is related to an intermittent circuit connection or component failure.

    1. With the scan tool, read DTCs and Freeze Frame Data and record on the repair order.
    2. With the scan tool, erase DTCs.
    3. Using the recorded Freeze Frame Data and the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    4. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

  2. CHECK FOR CORRELATING DTCS 
    1. Refer to the recorded DTCs.

      Are there any O2 Censor circuit low DTCs present?

      Yes 

      • Perform the diagnostics for the correlating DTC before continuing with this test procedure.

      No 

      • Go To  3
  3. CHECK THE INTAKE O2 SENSOR CIRCUITS FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect the Intake O2 Sensor harness connector.
    3. Disconnect the PCM C2 harness connector.
    4. Check for continuity between ground and the:
      • (K45) Intake O2 Sensor Signal circuit at the Intake O2 Sensor harness connector.
      • (K907) Intake O2 Sensor Return circuit at the Intake O2 Sensor harness connector.
      • (K735) Intake O2 Pump Current circuit at the Intake O2 Sensor harness connector.
      • (K732) Intake O2 Pump Cell Current Trim circuit at the Intake O2 Sensor harness connector.

      Is there continuity between ground and any of the above circuits?

      Yes 

      • Repair the circuit that showed continuity for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  4
  4. REPLACE THE INTAKE O2 SENSOR AND RETEST FOR DTC 
    1. Replace the Intake O2 Sensor in accordance with the Service Information and reconnect the harness connector. Refer to SENSOR, OXYGEN, REMOVAL AND INSTALLATION .
    2. With the scan tool, erase DTCs.
    3. Using the recorded Freeze Frame Data and the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    4. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  5

      No 

  5. CHECK RELATED PCM AND COMPONENT CONNECTIONS 
    1. Perform any Service Bulletins that apply.
    2. Disconnect all PCM harness connectors.
    3. Disconnect all related in-line harness connections (if equipped).
    4. Disconnect the related component harness connectors.
    5. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    9. With the scan tool, erase DTCs.
    10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    11. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No