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Home >> Alfa Romeo >> 2019 >> Giulia Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> 2.0L - DTCS P1128-00 To P1E39-00 >> DTC Troubleshooting >> P1188-00-Inlet Air Pressure Sensor Circuit Range Performance >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. With the scan tool, read Powertrain Control Module (PCM) DTCs and Freeze Frame Data and record on the repair order.
    2. Using the recorded Freeze Frame Data and the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    3. With the scan tool, erase DTCs.
    4. Test drive the vehicle. It may be necessary to operate the engine in higher RPM ranges to get the fault to set.

      Is the DTC active or pending?

      Yes 

      • Go To  2

      No 

  2. CHECK THE AIR FILTER AND INLET AIR DUCT FOR RESTRICTIONS 
    NOTE:

    A severe restriction in the inlet air system or turbo plumbing can cause the DTC to set when the engine is operated under higher RPM ranges due to the restricted air flow causing lower pressure in the inlet path.

    1. Remove the air cleaner cover and check the air filter for excessive dirt.
    2. Check the inlet fresh air duct for a restriction or damage. Visually inspect the corrugated portion of the duct and verify that the plastic duct does not feel soft or spongy. This could cause the duct to be sucked in during higher engine speeds.
      NOTE:

      If you suspect the duct may be too soft or spongy, remove the duct, clear the DTC, and test drive the vehicle at higher engine speeds and check for the fault to return.

      Is the air filter or fresh air duct restricted or damaged?

      Yes 

      No 

      • Go To  3
  3. CHECK THE TURBOCHARGER FOR RESTRICTIONS 
    1. Visually inspect the Turbocharger plumbing for a restriction or damage.

      Is the Turbocharger plumbing restricted or damaged?

      Yes 

      No 

      • Go To  4
  4. CHECK THE (K68) IAP SIGNAL CIRCUIT FOR HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the Mass Air Flow (MAF) Sensor harness connector.
    3. Disconnect the PCM C1 harness connector.
    4. Measure the resistance of the (K68) IAP Signal circuit between the Mass Air Flow (MAF) Sensor harness connector and the PCM C1 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  5

      No 

      • Repair the (K68) IAP Signal circuit for high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  5. CHECK THE (K852) 5-VOLT SUPPLY CIRCUIT FOR HIGH RESISTANCE 
    1. Measure the resistance of the (K852) 5-Volt Supply circuit between the Mass Air Flow (MAF) Sensor harness connector and the PCM C1 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  6

      No 

      • Repair the (K852) 5-Volt Supply circuit for high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. CHECK THE (K901) SENSOR GROUND CIRCUIT FOR HIGH RESISTANCE 
    1. Measure the resistance of the (K901) Sensor Ground circuit between the Mass Air Flow (MAF) Sensor harness connector and the PCM C1 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  7

      No 

      • Repair the (K901) Sensor Ground circuit for high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. REPLACE THE MAF SENSOR AND CHECK FOR DTC TO RETURN 
    1. Replace the Mass Air Flow (MAF) Sensor in accordance with the Service Information
    2. Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
    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 PCM DTCs.

      Is the DTC active or pending?

      Yes 

      • Go To  8

      No 

      • Test complete.
  8. 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 

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