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Home >> Alfa Romeo >> 2019 >> Giulia Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> 2.0L - DTCS P2237-00 To P2AE1-00 >> DTC Troubleshooting >> P24D6-00-EVAP System Pressure Sensor/Switch "B" Circuit Range/Performance >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR OTHER DTCS 
    1. Turn the ignition on.
    2. With the scan tool, read DTCs and record on the repair order.

      Are there any OBD Vent Valve DTCs present?

      Yes 

      • Perform the applicable diagnostic procedure(s). Refer to DTC INDEX .

      No 

      • Go To  2
  2. CHECK THE ESIM SWITCH STATE 
    1. Back probe and measure the voltage on the (K108) ESIM Signal circuit at the ESIM harness connector.
      NOTE:

      The ESIM connector must be plugged in during this step.

      NOTE:

      The voltage reading on the (K108) ESIM Signal circuit when the ESIM Switch is OPEN will be approximately 4.0 volts. When the ESIM Switch is CLOSED the voltage should be 0.0 volts on the (K108) ESIM Signal circuit.

      What is the ESIM Switch state?

      Open 

      • Go To  3

      Closed 

      • Go To  4
  3. EVAP SYSTEM INSPECTION 
    1. Turn the ignition off.
    2. Perform a visual inspection of the entire Evaporative Emission System for any of the following conditions:
      • Proper orientation of the ESIM switch wiring connector (3 O'clock position)
        • If the switch is not in the proper orientation, it may cause the weighted pressure and vacuum vents to intermittently not seal correctly. The ESIM wiring harness connector should be in the 3 O'clock position.
      • Damaged or missing components
      • Incorrect routing of hoses and tubes
      • Damaged or pinched hoses and tubes
      • Check the wiring harness routing for possible intermittent short to ground of the ESIM wiring

      Were any problems found?

      Yes 

      No 

      • Testing complete. The condition that caused the fault is intermittent and not present at this time.
  4. DISCONNECT THE CANISTER TUBE FROM THE PURGE SOLENOID AND CHECK ESIM STATE 
    1. Disconnect the purge tube at the Purge Solenoid (Canister side).
    2. Back probe and measure the voltage on the (K108) ESIM Signal circuit at the ESIM harness connector.

      Does the voltage on the (K108) ESIM Signal circuit change from 0.0 volts to approximately 4.0 with the Purge Tube disconnected?

      Yes 

      • Go To  5

      No 

      • Go To  6
  5. CHECK FOR THE OBD VENT VALVE STICKING CLOSED 
    1. Turn the ignition off.
    2. Remove the vacuum line from the OBD Vent Valve (this is the line that leads to the Purge Solenoid).
    3. Using a hand vacuum pump, apply vacuum to OBD Vent Valve.
    4. Turn the ignition on.
    5. Back probe the (K71) Evap Purge Control circuit at the OBD Vent Valve harness connector.
    6. Energize the OBD Vent Valve by connecting the (K71) Evap Purge Control circuit to ground.
      NOTE:

      The vacuum should purge immediately when the OBD Vent Valve is energized.

      Is the vacuum purged immediately when the OBD Vent Valve is energized?

      Yes 

      No 

      • Verify the OBD Vent Valve Filter is not plugged. If the filter is not plugged, replace the OBD Vent Valve in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. CHECK THE PURGE HOSE/TUBE FOR AN OBSTRUCTION 
    1. Remove the Fuel Cap or open the Capless Fuel Filler with the vent tool.
    2. Back probe and measure the voltage on the (K108) ESIM Signal circuit at the ESIM harness connector.

      Does the voltage on the (K108) ESIM Signal circuit change from 0.0 volts to approximately 4.0?

      Yes 

      • Repair the pinched or blocked purge tube between the Purge solenoid and the Canister.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  7
  7. CHECK THE ESIM SWITCH OPERATION 
    1. Disconnect the ESIM harness connector.
    2. Back probe and measure the voltage on the (K108) ESIM Signal circuit at the ESIM harness connector.

      Does the voltage on the (K108) ESIM Signal circuit change from 0.0 volts to approximately 4.0 when the switch is disconnected?

      Yes 

      • Replace the ESIM in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  8
  8. CHECK THE (K108) ESIM SIGNAL CIRCUIT FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect the PCM C1 harness connector.
    3. Check for continuity between ground and the (K108) ESIM Signal circuit at the ESIM harness connector.

      Is there continuity between ground and the (K108) ESIM Signal circuit?

      Yes 

      • Repair the (K108) ESIM Signal circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  9
  9. CHECK FOR A SHORT BETWEEN THE (K108) ESIM SIGNAL CIRCUIT AND THE ESIM GROUND CIRCUIT 
    1. Check for continuity between the (K108) ESIM Signal circuit and the ESIM Ground circuit at the ESIM Switch harness connector.

      Is there continuity between the (K108) ESIM Signal circuit and the ESIM Ground circuit?

      Yes 

      • Repair the short between the (K108) ESIM Signal circuit and the ESIM Ground circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  10
  10. 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 

      • The wiring or poor connection problem has been repaired.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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