2014 Jeep Wrangler JK Factory Service Manual 28 - DTC-Based Diagnostics

P0441-EVAP PURGE SYSTEM PERFORMANCE

For a complete wiring diagram, refer to the Wiring Information.





Theory of Operation

EVAP SYSTEM COMPONENTS

CALLOUT

DESCRIPTION

1

Filter

2

ESIM Switch

3

Evaporative Canister

4

Fuel Tank Vent (Check Valve)

5

Control Valve

6

Inlet Check Valve

7

Fuel Tank Pressure Sensor

8

To Purge System

9

Fuel Fill Tube

The Evaporative Purge Monitor tests the integrity of the hoses/tube between the throttle body/intake and the fuel tank. The monitor will be enabled under either a Small Leak test or it will run during a Large Leak test (This is when Small Leak test does not pass). During a Small Leak test, the monitor will first evaluate the delta pressure on the Fuel Tank Pressure (FTP) sensor while normal purge control is active. If the monitor does not pass within a calibrated amount of time, then an intrusive monitor will be enabled. This intrusive monitor will ramp in the purge flow to a target amount while evaluating the delta pressure in the entire system. If the delta pressure between purge off and purge on exceeds a calibrated amount, then the monitor will ramp out the purge flow and evaluate the delta pressure between the high flow and the new low flow target. If the delta pressure is less than a calibrated threshold then the monitor will pass.


Possible Causes

FUEL TANK PRESSURE (FTP) SENSOR 5–VOLT SUPPLY OPEN CIRCUIT OR EXCESSIVE RESISTANCE
EVAP PURGE SOLENOID VACUUM SUPPLY
EVAP PURGE SOLENOID VACUUM SUPPLY
EVAPORATIVE PURGE HOSE/TUBE AND FRESH AIR FILTER OBSTRUCTION
EVAP PURGE SOLENOID
FUEL TANK PRESSURE SENSOR
OBSTRUCTED ESIM FRESH AIR FILTER
OBSTRUCTED LINE BETWEEN THE FUEL TANK AND CANISTER
POWERTRAIN CONTROL MODULE (PCM)

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 28 - DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure).


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.


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


2. ACTIVE DTC



NOTE: If P0443 is set along with this DTC, perform the diagnostic procedure for P0443 before continuing with this test.

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.


Is the DTC Active or Pending at this time?

Yes


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


No


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


No


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


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


No


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