2012 Jeep Wrangler JK Factory Service Manual 28 - DTC-Based Diagnostics

P0455-EVAP PURGE SYSTEM LARGE LEAK

P0455-EVAP PURGE SYSTEM LARGE LEAK

Special Tools: Click to display a list of tools used in this procedure

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


Theory of Operation

EVAP SYSTEM COMPONENTS

CALL OUT

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 is a two stage test and runs only after the Evaporative system passes the small leak test. Stage one is non-intrusive. The Powertrain Control Module (PCM) monitors the purge vapor ratio and the Evaporative System Integrity Monitor (ESIM) switch closed ratio. If the purge vapor ratio is above a calculated value, the monitor passes. If the ESIM switch closed ratio is greater than calculated value when purge flow is greater than a minimum value, the monitor passes. Stage two is an intrusive test and runs only if stage one does not pass. The PCM commands the purge solenoid to flow at a specified rate to force the purge vapor ratio to update. The ratio is compared to a calibrated specification. If it is less than specified, a one trip failure is recorded. This test can detect if the purge hose is off, obstructed or the purge valve is not operational.


Possible Causes

EVAPORATIVE PURGE SYSTEM LEAK
EVAP PURGE SOLENOID
EVAPORATIVE SYSTEM INTEGRITY MONITOR SWITCH

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


1. DTC IS ACTIVE



NOTE: If any Sensor Reference DTCs are present, perform the applicable diagnostic procedure before continuing with this test.
1. Ignition on, engine not running.
2. With the scan tool, Clear DTCs in the PCM.
3. Start the engine.
4. Allow the engine to reach normal operating temperature.
5. With the scan tool, select View DTCs.


Is the status Active for this DTC?

Yes


No


2. CHECK THE AIR FILTER

1. Turn the ignition off.
2. Remove and inspect the Air Filter for soiling or excessive dirt and debris which may cause air flow restriction.
3. Check the Inlet Tube for signs of excessive dirt, snow, or ice restricting airflow into the Air Filter Box.


Were any problems found?

Yes


No


3. CHECK FOR INTAKE SYSTEM RESTRICTIONS

1. Turn the ignition off.
2. Inspect all air intake, crankcase vent and Turbocharger related hoses/tubes and connections.
3. Inspect the Charge Air Cooler hoses/tubes and connections.
4. Inspect the EGR Air Flow Control Valve to ensure the valve is not stuck in the closed position.


Were any problems found?

Yes


No


4. CHECK FOR INTAKE SYSTEM AIR LEAKS

1. Remove the Crankcase Vent Heater.
2. Remove the Mass Air Flow Sensor from the Turbocharger Inlet Tube.
3. Seal off and/or plug the Turbocharger Inlet Tube where the MAF sensor was removed.
4. Connect the Evaporative Emissions Leak Detector (EELD) Kit, EELD And Accessory 8404C to the Crankcase Vent Heater port in the intake duct and begin injecting smoke into the intake system.
5. Observe all intake system components for evidence of smoke leakage.


Is there evidence of smoke leakage?

Yes


No


5. CHECK THE EXHAUST SYSTEM FOR LEAKS OR RESTRICTIONS

1. Visually inspect the entire exhaust system for damage, leaks or restrictions.


Were any problems found?

Yes


No


6. CHECK THE FUEL DELIVERY SYSTEM

1. Perform the CHECKING THE FUEL DELIVERY SYSTEM diagnostic procedure. (Refer to 29 - Non-DTC Diagnostics/Drivability - Diesel - Diagnosis and Testing).


Were any problems found?

Yes


No


7. CHECK THE (K355) EXHAUST DIFFERENTIAL PRESSURE SENSOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the Exhaust Differential Pressure Sensor harness connector.
3. Disconnect the PCM C1 harness connector.
4. Measure the resistance of the (K355) Exhaust Differential Pressure Sensor Signal circuit between the Exhaust Differential Pressure Sensor harness connector and the Powertrain Control Module (PCM) harness connector.


Is the resistance below 5.0 Ohms?

Yes


No


8. CHECK THE (K951) EXHAUST DIFFERENTIAL PRESSURE SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K951) Exhaust Differential Pressure Sensor Ground circuit between the Exhaust Differential Pressure Sensor harness connector and the Powertrain Control Module (PCM) harness connector.


Is the resistance below 5.0 Ohms?

Yes


No


9. EXHAUST DIFFERENTIAL PRESSURE SENSOR

1. Turn the ignition off.
2. Reconnect the PCM C1 harness connector.
3. Replace the Exhaust Differential Pressure Sensor in accordance with the service information.
4. Turn the ignition on.
5. With the scan tool, clear DTCs.
6. Start the engine.
7. Allow the engine to reach normal operating temperature.
8. With the scan tool, select View DTCs.


Did the DTC return?

Yes


No


10. PARTICULATE FILTER REGENERATION

1. Turn the ignition on.
2. With the scan tool, erase DTCs in the PCM.
3. Start and idle the engine.
4. With the scan tool, perform the Diesel Particulate Filter Regeneration procedure.
5. After this procedure is complete, turn the ignition off for 60 seconds.
6. Test drive the vehicle.
7. With the scan tool, view DTCs in the PCM.


Is the status Active for this DTC?

Yes


No


11. POWERTRAIN CONTROL MODULE

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Exhaust Differential Pressure Sensor and the Powertrain Control Module.
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Perform any Technical Service Bulletins that may apply.


Were any problems found?

Yes


No