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Home >> Jeep >> 2014 >> Wrangler Sahara, Standard Trans >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> 3.6L - DTCS P0157 To P0457 >> Diagnosis And Testing >> P0441-EVAP Purge System Performance >> Diagnostic Test

Diagnostic Test

  1. VEHICLE HISTORY AND SERVICE BULLETIN INVESTIGATION 
    1. Ignition on, engine not running.
    2. With the scan tool, select View DTCs and record the related Freeze Frame data if any DTCs are present.
    3. Whether or not any DTCs are Active you will want to check the following items which may assist in repairing the customer's complaint successfully:
      • Check the vehicle's repair history.
      • If the vehicle has a repair history that pertains to the customer's current complaint, review the repair.
      • Inspect the vehicle for any aftermarket accessories that may have been installed incorrectly.
      • Check for any service bulletin(s) related to the customer's complaint or DTCs.
      • If a service bulletin applies, follow the instructions of the service bulletin.

      Choose the following scenario that best applies.

      The service bulletin repaired the customer's complaint. 

      • Testing complete.

      A DTC is present, no service bulletins apply or the service bulletin didn't repair the customer's complaint. 

      • Go To  2
  2. ACTIVE DTC 
    NOTE:

    If P0443 is set along with this DTC, perform the diagnostic procedure for P0443 before continuing with this test. Refer to P0443-EVAP PURGE SOLENOID CIRCUIT .

    NOTE:

    If the customer is experiencing an early fuel shut off during the fuel filling process along with P0440, P0441 and P0452 setting, you need to check for restrictions in the Evaporative Purge tubes/hoses as well as the Fresh Air Filter before continuing.

    1. Using the scan tool, perform the ESIM FORCED MONITOR TEST. Allow the test to complete.
    2. With the scan tool, select View DTCs.
      NOTE:

      If any other DTC sets, active or pending, perform the diagnostic procedure for that DTC before proceeding with this test. Refer to DTC INDEX .

      Is the DTC Active or Pending at this time?

      Yes 

      • Go To  3

      No 

  3. CHECK THE FUEL TANK PRESSURE (FTP) SENSOR 5-VOLT SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    NOTE:

    Diagnose and repair any system voltage or sensor supply voltage DTC's before continuing with this test.

    Turn the ignition off.

    1. Disconnect the FTP Sensor harness connector.
    2. Ignition on, engine not running.
    3. Measure the voltage on the FTP Sensor 5-Volt Supply circuit at the FTP Sensor harness connector.

      Is the voltage between 4.8 to 5.2 volts?

      Yes 

      • Go To  4

      No 

      • Repair the Fuel Tank Pressure Sensor 5-Volt Supply circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  4. FUEL TANK PRESSURE (FTP) SENSOR 
    1. Turn the ignition off.
    2. Reconnect the FTP Sensor harness connector.
    3. Remove the fuel filler cap.
    4. Ignition on, engine not running.
    5. With a voltmeter, back-probe the FTP Sensor Signal circuit at the FTP Sensor harness connector.

      Is the voltage between 2.3 to 2.7 volts?

      Yes 

      • Go To  5

      No 

      • Verify that there is good pin to terminal contact in the Fuel Tank Pressure Sensor and Powertrain Control Module connectors. Replace the FTP Sensor if no problems were found with the connectors. Refer to SENSOR, FUEL TANK PRESSURE, REMOVAL .
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  5. EVAP PURGE HOSE/TUBE AND FRESH AIR FILTER OBSTRUCTION 
    1. Inspect the Evaporative Purge hose/tube for proper routing and installation between the Evap Purge Solenoid and the Fuel Tank and between the Fuel Tank and the Evap Purge Canister.
    2. Make sure the hose/tube and fresh air filter are not damaged, kinked and free from any obstructions.

      Were any problems found?

      Yes 

      No 

      • Go To  6
  6. EVAP PURGE SOLENOID 
    NOTE:

    After disconnecting the Evap Purge Solenoid vacuum connections, inspect the lines and solenoid for signs of contamination.

    1. Using a hand vacuum pump, apply 10 in Hg to the "CAN" side of the Evap Purge Solenoid.
      NOTE:

      The solenoid should hold vacuum for a minimum of 15 seconds.

    2. Ignition on, engine not running.
    3. With the scan tool, actuate the Evap Purge Solenoid to the ON position.
      NOTE:

      The vacuum should drop when the solenoid is actuated.

      Does the solenoid function as described above?

      Yes 

      • Go To  7

      No 

      • Verify that there is good pin to terminal contact in the Solenoid and the Powertrain Control Module connectors. Replace the Evap Purge Solenoid if no problems were found in the connectors.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. POWERTRAIN CONTROL MODULE (PCM) 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Evap Purge Solenoid Assembly, ESIM switch and the Powertrain Control Module (PCM).
    2. Look for any chafed, pierced, pinched or partially broken wires.
    3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the switch, Solenoid and the Powertrain Control Module connectors.
    4. Perform any Technical Service Bulletins that may apply.

      Were there any problems found?

      Yes 

      No 

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