Emissions Control: Diagnosis Dodge Avenger II facelift

DIAGNOSIS AND TESTING - VEHICLE DOES NOT FILL

Scheme 15

The fuel tank pressure sensor provides the PCM with information on vapor pressure inside the fuel tank. The sensor is a diaphragm-type pressure sensor and varies its voltage output depending on fuel tank pressure. When the fuel tank isolation valve is activated (closed), preventing fuel vapors from leaving the tank, the PCM will monitor the fuel tank pressure sensor to prevent pressure from increasing or decreasing to an unsafe level.

Excessive fuel tank pressure could cause fuel vapors to vent out the fuel filler cap or damage system components while insufficient fuel tank pressure (vacuum) caused by lack of air entering the tank to take the place of consumed fuel could lead to collapsed tank, lines or loss of fuel pressure.

Scheme 16

Scheme 17

Scheme 18

1. Disconnect and isolate the negative battery cable.
2. Remove the fuel filler cap to relieve tank pressure.
3. Raise and support the vehicle. Refer to «HOISTING, STANDARD PROCEDURE»(ref-485472-S37758686622012071300000) .
4. Remove the left rear wheel splash shield. Refer to «SHIELD, SPLASH, FRONT WHEELHOUSE, REMOVAL»(ref-485483-S05679842352012071300000) or «SHIELD, SPLASH, REAR WHEELHOUSE, REMOVAL»(ref-485483-S03877425932012071300000) .
5. Disconnect the fuel tank pressure sensor electrical connector (1).
6. Carefully raise the retaining tab (2), rotate and remove the fuel tank pressure sensor (1) from the fuel tank vent tube.
7. The fuel tank pressure sensor seal (1) can be reused if not damaged.

Scheme 19

1. The fuel tank pressure sensor seal (1) can be reused if not damaged.
2. Install the fuel tank pressure sensor (1) into the fuel tank vent tube and rotate into position.
3. Connect the fuel tank pressure sensor electrical connector (1).
4. Install the left rear wheel splash shield. Refer to «SHIELD, SPLASH, FRONT WHEELHOUSE, INSTALLATION»(ref-485483-S00528336772012071300000) or «SHIELD, SPLASH, REAR WHEELHOUSE, INSTALLATION»(ref-485483-S05575578442012071300000) .
5. Lower the vehicle.
6. Install the fuel filler cap.
7. Connect the negative battery cable and tighten nut to 5 N.m (45 in. lbs.).

Scheme 20

1. Disconnect and isolate negative battery cable at battery.
2. Remove the PCM. Refer to «MODULE, POWERTRAIN CONTROL, REMOVAL»(ref-485482-S06048014282012071300000) .
3. Disconnect electrical connector (5) from evaporator purge solenoid (1).
4. Remove purge hose (4) from evaporator purge solenoid (1).
5. Remove quick connect fuel tank hose (3) from evaporator purge solenoid (1).
6. Release tab (2) to remove evaporator purge solenoid (1) from bracket.

DIAGNOSIS AND TESTING - PCV SYSTEM

1. Remove the make-up air hose from the air cleaner body. Hold a piece of stiff paper (parts tag) loosely over the end of the make-up air hose.
2. After allowing approximately one minute for crankcase pressure to reduce, the paper should draw up against the hose with noticeable force. If the engine does not draw the paper against the hose end Inspect the PCV valve and hose for blockage.
3. Turn the engine off. Remove the PCV valve. The valve should rattle when shaken.
4. Replace the PCV valve and retest the system if it does not operate as described in the preceding tests. Do not attempt to clean the old PCV valve.

Scheme 21

Scheme 22

1. Remove the engine cover.
2. Remove the hose from the PCV valve.
3. Unscrew the PCV valve.

Scheme 23

Scheme 24

1. Remove the hose (1) from the PCV valve (2).
2. Remove the three screws (2) and the PCV valve (1) from the right cylinder head cover.

TEST SEQUENCE

In many instances, emissions systems must fail diagnostic tests more than once before the PCM illuminates the MIL. These tests are known as 'two trip monitors.' Other tests that turn the MIL lamp on after a single failure are known as 'one trip monitors.' A trip is defined as 'start the vehicle and operate it to meet the criteria necessary to run the given monitor.'

Many of the diagnostic tests must be performed under certain operating conditions. However, there are times when tests cannot be run because another test is in progress (conflict), another test has failed (pending) or the Task Manager has set a fault that may cause a failure of the test (suspend).

DIAGNOSTIC TROUBLE CODES (DTCS)

With OBD II, different DTC faults have different priorities according to regulations. As a result, the priorities determine MIL illumination and DTC erasure. DTCs are entered according to individual priority. DTCs with a higher priority overwrite lower priority DTCs.

Priorities

1. Priority 1 One-Trip Failure of Non-Fuel or Non-Mis-Fire Fault (e.g., Cat Mon Failure)
2. Priority 3 Matured Fault (either One-Trip or Two-Trip) Non-Fuel AND Non-Mis-Fire
3. Priority 4 One-Trip Failure of Fuel System or Mis-Fire Fault
4. Priority 6 Matured Fault for Fuel System or Mis-Fire (either One-Trip or Two-Trip)

Non-emissions related failures have no priority. One trip failures of two trip faults have low priority. Two trip failures or matured faults have higher priority. One and two trip failures of fuel system and misfire monitor take precedence over non-fuel system and non-misfire failures.

DTC SELF ERASURE

With one trip components or systems, the MIL is illuminated upon test failure and DTCs are stored.

Two trip monitors are components requiring failure in two consecutive trips for MIL illumination. Upon failure of the first test, the Task Manager enters a maturing code. If the component fails the test for a second time the code matures and a DTC is set.

After three good trips the MIL is extinguished and the Task Manager automatically switches the trip counter to a warm-up cycle counter. DTCs are automatically erased following 40 warm-up cycles if the component does not fail again.

For misfire and fuel system monitors, the component must pass the test under a Similar Conditions Window in order to record a good trip. A Similar Conditions Window is when engine RPM is within ±375 RPM and load is within ±20% of when the fault occurred.

Note. It is important to understand that a component does not have to fail under a similar window of operation to mature. It must pass the test under a Similar Conditions Window when it failed to record a Good Trip for DTC erasure for misfire and fuel system monitors.

DTCs can be erased anytime with a scan tool. Erasing the DTC with the scan tool erases all OBD II information. The scan tool automatically displays a warning that erasing the DTC will also erase all OBD II monitor data. This includes all counter information for warm-up cycles, trips and Freeze Frame.