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Home >> Jeep >> 2018 >> Compass Trailhawk >> Repair and Diagnosis >> Engine Performance >> System >> 2.4L - DTCS P0223 To P0685 >> DTC Troubleshooting >> P0440-General EVAP System Failure >> Diagnostic Test
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Diagnostic Test

  1. CHECK THE EVAPORATIVE SYSTEM FOR EXCESSIVE VACUUM BUILD-UP 
    NOTE:

    If the customer is experiencing an early fuel shut off during the fuel filling process in addition to DTC P0440, P0441, or P0452, check for restrictions in the tubes/hoses between the Fuel tank and Evaporative Canister, ESIM, and the ESIM Vent Filter before continuing.

    1. Start the engine.
    2. With the scan tool, Monitor the Purge system allowing it to run longer than 30 seconds.
    3. Turn the engine off, ignition on.
    4. With the scan tool, read the Fuel Tank Pressure (FTP) Sensor value.
      NOTE:

      In a normally operating system, the FTP Sensor should not exceed -0.07 to -0.14 psi on the scan tool due to the operation of the ESIM.

      Is the FTP Sensor reading -0.25 psi or below?

      Yes 

      • Go To  2

      No 

      • Go To  3
  2. EVAPORATIVE PURGE HOSE/TUBE AND VENT FILTER OBSTRUCTION 
    NOTE:

    It is important not to disturb the ESIM when removing the Vent Filter. Moving the ESIM could cause a stuck ESIM check valve to become free.

    1. Remove the Vent Filter.

      Did the FTP Sensor reading rise to -0.14 psi or above on the scan tool?

      Yes 

      • Repair the obstruction in the vent tube or filter.
      • Run the ESIM Forced Monitor Test again to verify the repair is complete.

      No 

      • Replace the ESIM in accordance with the Service Information.
      • Run the ESIM Forced Monitor Test to verify the repair is complete.
  3. CHECK FOR AN ACTIVE CONDITION 
    1. With the scan tool, navigate to System Test and start the ESIM Forced Monitor Test. Allow the test to run until finished.
    2. Read the Large Leak test results.
      NOTE:

      This is a test of the overall operation of the evaporative system components. It does not necessarily indicate that a large leak was the failure.

      Did the Large Leak test pass or fail?

      Passed 

      • Go To  4

      Failed 

      • Go To  5
  4. EVAPORATIVE SYSTEM INSPECTION 
    1. Turn the ignition off.
    2. The condition that caused the fault is intermittent and not present at this time. 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)
      • Holes or cracks
      • Loose seal points
      • Damaged or missing components
      • Incorrect routing of hoses and tubes
      • Loose or missing Fuel Filler Cap (if applicable) or seal
      • Damaged seal points on the Fuel Filler Cap (if applicable) or Capless Fuel Filler Assembly
      • Ice or intermittent blockage in the ESIM Vent Filter or hose

      Were any problems found?

      Yes 

      No 

      • Testing complete.
  5. CHECK THE EVAPORATIVE SYSTEM PERFORMANCE TO DETERMINE IF FAILURE IS ELECTRICAL OR MECHANICAL 
    1. Start the engine.
    2. Allow the vehicle to idle long enough for the Purge Solenoid to cycle on.
      NOTE:

      With the scan tool, view the duty cycle of the Purge Solenoid on the Data Display to ensure that the Purge Solenoid is on.

      NOTE:

      Normally, the Fuel Tank Pressure Sensor should read approximately -0.07 to -0.014 psi on the scan tool and the ESIM Switch should display as CLOSED on the scan tool with the Purge Solenoid on.

      Which of the following conditions are present?

      ESIM Switch is OPEN and Fuel Tank Pressure Sensor DOES NOT read negative PSI or vacuum: 

      • Go To  10

      ESIM Switch is OPEN but the Fuel Tank Pressure Sensor DOES read negative PSI or vacuum: 

      • Go To 6
  6. CHECK THE ESIM SWITCH 
    1. Turn the ignition off.
    2. Disconnect the ESIM Switch harness connector.
    3. Turn the ignition on.
    4. With the scan tool, read the ESIM Switch state.
    5. Connect a jumper between the (K108) ESIM Signal circuit and the ESIM Ground circuit at the ESIM Switch harness connector.
    6. With the scan tool, read the ESIM Switch state.

      Does the ESIM Switch state change from OPEN when disconnected to CLOSED when the jumper is installed?

      Yes 

      • Replace the ESIM in accordance with the Service Information.
      • Run the ESIM Forced Monitor Test again to verify the repair is complete.

      No 

      • Go To  7
  7. CHECK THE (K108) ESIM SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the PCM C1 harness connector.
      CAUTION:

      Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.

    3. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
    4. Measure the resistance of the (K108) ESIM Signal circuit between the ESIM Switch harness connector and the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  8

      No 

      • Repair the (K108) ESIM Signal circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  8. CHECK THE (Z942) ESIM GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance between ground and the (Z942) ESIM Ground circuit at the ESIM Switch harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  9

      No 

      • Repair the (Z942) ESIM Ground circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  9. 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 

  10. CHECK THE PURGE SOLENOID VACUUM SUPPLY 
    1. Turn the engine off.
    2. Remove the Purge Tube (Solenoid to Canister) from the outlet side of the Purge Solenoid.
    3. Start the engine and allow it to idle until the Purge Solenoid cycles on.
    4. Check for vacuum coming from the Purge Solenoid.

      Is engine vacuum present?

      Yes 

      • Go To  11

      No 

      • Check the vacuum supply to the solenoid from the Intake Manifold. If no vacuum is present, repair the cause of the loss of vacuum to the solenoid. If engine vacuum is present, replace the Purge Solenoid.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  11. CHECK THE PURGE TUBE FOR A RESTRICTION 
    1. Turn the engine off.
    2. Attach a hand held vacuum pump into the Purge Tube.
      NOTE:

      Ensure that there is a good seal between the vacuum pump nipple and the Purge Tube.

    3. Pump the vacuum pump up to 10 - 15 times depending on the fuel level.

      Which of the following conditions are present?

      Vacuum IS  present on the vacuum pump, the ESIM Switch is OPEN and the FTP Sensor does not show a negative PSI or vacuum

      • Repair the restriction between the Purge Solenoid and the ESIM.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      Vacuum IS NOT  present on the vacuum pump, the ESIM Switch is OPEN and the FTP Sensor does not show a negative PSI or vacuum

      • Go To  12
  12. EVAPORATIVE EMISSION LEAK DETECTION 
    WARNING:

    Keep lit cigarettes, sparks, flames, and other ignition sources away from the test area to prevent the ignition of explosive gases. Keep the test area well ventilated. Failure to do so may result in possible serious or fatal injury.

    1. To continue testing, you will need the Evaporative Leak Detector (EELD) and Accessory Kit (special tool #8404C, Kit, EELD And Accessory).
    2. Connect the red power lead of EELD to the battery positive terminal and the black ground lead to battery negative terminal.
    3. Connect shop air to the EELD.
    4. Remove the ESIM Vent Filter and install the appropriate Smoke Machine Adaptors (special tool #8404-ADP, Smoke Machine Adapters) into the vent line.
    5. Connect the SMOKE supply tip (black hose) to the adapter.
    6. Set the smoke/air control switch to SMOKE.
    7. Press and hold the remote smoke/air start button to allow the system to fill with smoke.
    8. While still holding the remote smoke/air start button, use the White Light (special tool #8404-CLL, Light, White) to follow the Evap system path, and look for the source of the leak indicated by exiting smoke.
    9. If a leak is concealed from view (i.e., top of fuel tank), release the remote smoke/air start button, and use the Ultraviolet (UV) Light (special tool #8404-UVL, Light, UV) and the Yellow Goggles (special tool #8404-20, Goggles, Yellow) to look for residual traces of dye that are left behind by the smoke.
      NOTE:

      The exiting smoke deposits a residual fluid that is either bright green, yellow or purple in color when viewed with a UV light.

      Select the appropriate response from the list below:

      A leak was found at the Fuel Cap (if applicable) or Fuel Filler Tube Assembly 

      • Perform the appropriate repair by replacing the Fuel Filler Tube Assembly and/or the Fuel Cap (if applicable).
      • Run the ESIM Forced Monitor Test again to verify the repair is complete.

      A leak was found in the Evaporative System 

      • If the leak is at a hose connection, remove the hose, then reconnect the hose and check for a leak again. All other leaks, repair as necessary.
      • Run the ESIM Forced Monitor Test again to verify the repair is complete.
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