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Home >> Jeep >> 2020 >> Compass Trailhawk >> Repair and Diagnosis >> Engine Performance >> System >> 2.4L - DTCS P0141 To P0600 >> DTC Troubleshooting >> P0441-EVAP Purge System 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 Purge Solenoid Control circuit, small or large Evap System leak DTCs active or pending?

      Yes 

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

      No 

      • Go to 2
  2. CHECK FOR AN ACTIVE CONDITION 
    NOTE:

    The ESIM/Purge Flow Forced Monitor Test is designed to help determine if there is an issue with the Evaporative system, and if so what part of the system is failing. This routine runs the General Evap, Large Leak and Purge Performance diagnostics, and makes a pass/fail determination. Note: The values in the Pass Threshold column are unique to each vehicle application. 

    1. Turn the ignition on.
      NOTE:

      Before starting the "ESIM/Purge Flow Forced Monitor" routine with the scan tool, vent the pressure or vacuum in the Fuel Tank by opening the Capless Fuel Filler with the vent or removing and installing the Fuel Cap. This will bring the Fuel Tank pressure closer to atmosphere and give more consistent results during the scan tool routine.

    2. With the scan tool, start the "ESIM/Purge Flow Forced Monitor" test and analyze the results.
      • The top four rows show the live data readings while the test is running for the key components used in leak detection (ESIM Switch State) and purge performance (FTP Sensor), along with the Purge Solenoid which is used for both diagnostics.
      • Lowest Recorded FTP Sensor Reading row  - Shows the peak Fuel Tank vacuum that was created during the Purge Solenoid activation.
      • Range Reference (FTP Sensor) row  - Displays the starting FTP Sensor value taken before the Purge Solenoid is activated. If the starting value is not between the minimum and maximum values in the Pass Threshold column, a fail is recorded. Even if the Range Reference fails, the purge monitor test is still performed and will pass/fail based on the side 1 and side 2 results.
      • Side 1 (FTP Sensor pressure change) row  - The Purge Solenoid is commanded on for a calibrated period with the intent of decreasing pressure (more vacuum) in the Fuel Tank. The Actual Result  displays the delta pressure change in the FTP Sensor reading from the initial range reference value during this period. A positive value indicates a pressure increase and a negative value indicates a pressure decrease from the initial reading.  If the Actual Result shows that pressure decreased more than the Pass Threshold  value the diagnostic will pass (for example, using a -50 Pa Pass Threshold, a pressure decrease of -20 Pa fails and a pressure decrease of -60 Pa passes).
      • Side 2 (FTP Sensor pressure change) row  - During side 2 evaluation, the Purge Solenoid is commanded off with the intent of increasing pressure. The Actual Result  displays the pressure change in the FTP Sensor reading. A positive value indicates that pressure increased and a negative value indicates that pressure decreased after the Purge Solenoid was turned off.  If the pressure does not increase more than the value in the Pass Threshold column the diagnostic will fail.
      • General Evap (ESIM Switch) row  - Displays whether the ESIM Switch closed while the Purge Solenoid was commanded on. If the ESIM Switch did not close at any time during Purge actuation the General Evap diagnostic fails.
      • Large Leak (ESIM Switch Closed) row  - Displays results from the large leak test. The Pass Threshold column shows the amount of time the ESIM Switch must remain closed after the Purge Solenoid is turned off to record a pass. If the time in the Actual Result column reaches the threshold the system is passing. A system with a leak will display time values less than the threshold and time values closer to the threshold are indicative of smaller leaks.

      Pick the scenario that best matches the results from the routine?

      All of the monitors pass and side 1 and side 2 actual pressure changes are well beyond the pass thresholds: 

      • The purge system is passing and not in need of repair at this time.

      All of the monitors pass but side 1 and side 2 actual pressure changes are close to the pass thresholds: 

      • The system is passing but there could be a partial restriction in the Intake Manifold or manifold hose (Call-out 8 in the Evap system figure) if only the P0441 DTC was present.

      Side 1 passed/Side 2 failed/the vacuum created was very high (well below the ESIM regulation point of approximately -500 Pa) with the Purge Solenoid commanded on and holds steady or dissipates very slowly after the Purge Solenoid is commanded off: 

      • Repair the restriction at the Fresh Air Inlet Filter or hose (Call-outs 1 and 2 in the Evap system figure). If removing the Fresh Air Inlet Filter and hose does not reduce the vacuum to the ESIM regulation point (approximately -500 Pa), the ESIM internal vacuum vent valve is stuck closed.
      • Perform the "ESIM/Purge Flow Forced Monitor" test to confirm system is repaired.

      Side 1 and/or side 2 failed (FTP Sensor reading doesn't change or changes very little), ESIM Switch closes and large leak fails: 

      • Check for a broken, plugged or damaged Canister Tube (Call-out 5 in the Evap system figure), Recirculation Tube (Call-out 9 in the Evap system figure), damaged Evaporative Charcoal Canister (Call-out 4 in the Evap system figure) or a partially broken Purge Tube (Call-out 6 in the Evap system figure).
      • Perform the "ESIM/Purge Flow Forced Monitor" test to confirm system is repaired.

      Side 1 and/or side 2 failed (FTP Sensor reading doesn't change or changes very little), ESIM Switch closes and large leak passes: 

      • Go to 3

      Side 1 and/or side 2 failed and ESIM Switch does not close or you suspect a possible faulty Purge Solenoid: 

      • Go to 5
  3. CHECK FOR A BLOCKAGE BETWEEN THE CHARCOAL CANISTER AND THE FUEL TANK PRESSURE SENSOR 
    1. Turn the ignition off.
    2. Remove the Recirculation Tube (Call-out 9 in the Evap system figure) from the FTP Sensor.
    3. Attach a hand vacuum pump to the FTP Sensor.
    4. While monitoring the FTP Sensor reading on the scan tool, apply vacuum to the sensor.

      Does the FTP Sensor value change when applying vacuum to the sensor?

      Yes 

      • Repair the restriction in the Canister Tube (Call-out 5 in the Evap system figure), Recirculation Tube (Call-out 9 in the Evap system figure) or Multi-Function Control Valve (Call-out 14 in the Evap system figure).
      • Perform the "ESIM/Purge Flow Forced Monitor" test to confirm system is repaired.

      No 

      • Go to 4
  4. CHECK THE (K859) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the FTP Sensor harness connector.
    3. Turn the ignition on.
    4. Measure the voltage on the (K859) 5-Volt Supply circuit at the FTP Sensor harness connector.
      NOTE:

      If the 5-Volt Supply circuit to the sensor is lost it can cause the sensor voltage signal to stick mid-range between the normal operating parameters. This can cause this DTC to set because the PCM does not detect a change in the FTP Sensor signal as expected during purge operation.

      Is the voltage between 4.9 to 5.1 volts?

      Yes 

      • Verify that there is good pin to terminal contact in the Fuel Tank Pressure Sensor connector. If no problems were found with the connector, replace the Fuel Tank Pressure Sensor in accordance with the Service Information. Refer to SENSOR, FUEL TANK PRESSURE, REMOVAL AND INSTALLATION .
      • Perform the "ESIM/Purge Flow Forced Monitor" test to confirm system is repaired.

      No 

      • Repair the (K859) 5-Volt Supply circuit for an open or high resistance.
      • Perform the "ESIM/Purge Flow Forced Monitor" test to confirm system is repaired.
  5. CHECK THE INTAKE MANIFOLD PORT FOR A RESTRICTION OR BLOCKAGE 
    NOTE:

    It is important to note that a restriction in the vacuum supply may not decrease the vacuum reading but can still reduce the flow causing the purge performance diagnostic to fail. Therefore the vacuum port on the Intake Manifold and the Manifold Hose need to be inspected closely even if vacuum is present.

    1. Remove the Manifold Hose vacuum line at the Intake Manifold vacuum port.
    2. Visually inspect inside the vacuum port for restriction or blockage due to flashing or carbon build up.

      Is the port restricted?

      Yes 

      • Repair the restriction in the vacuum port on the Intake Manifold.
      • Perform the "ESIM/Purge Flow Forced Monitor" test to confirm system is repaired.

      No 

      • Go to 6
  6. CHECK THE MANIFOLD HOSE AND THE VACUUM SUPPLY AT THE INLET OF THE PURGE SOLENOID 
    1. Install the Manifold Hose vacuum line to the Intake Manifold port.
    2. Remove the Manifold Hose vacuum line at the inlet port of the Purge Solenoid (this is the vacuum line that comes from the Intake Manifold).
    3. Start the engine and allow it to idle.
    4. Check the vacuum supply to the Purge Solenoid.

      Is there sufficient engine vacuum present?

      Yes 

      • Go to 7

      No 

      • Repair the broken or plugged Manifold Hose (Call-out 8 in the Evap system figure).
      • Perform the "ESIM/Purge Flow Forced Monitor" test to confirm system is repaired.
  7. CHECK THE VACUUM SUPPLY AT THE OUTLET OF THE PURGE SOLENOID 
    1. Turn the ignition off.
    2. Reconnect the Manifold Hose vacuum line at the inlet port of the Purge Solenoid.
    3. Remove the vacuum line at the outlet port of the Purge Solenoid (this is the line that leads to the Evaporative Canister).
    4. Connect a vacuum gauge to the outlet port of the Purge Solenoid.
    5. Start the engine and allow it to idle long enough for the Purge Solenoid to cycle on.
    6. Check the vacuum supply at the Purge Solenoid outlet port.

      Is there sufficient engine vacuum present?

      Yes 

      • Check the Purge Tube (Call-out 6 in the Evap system figure) for signs of damage (broken, disconnected or plugged).
      • Perform the "ESIM/Purge Flow Forced Monitor" test to confirm system is repaired.

      No 

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