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Home >> Jeep >> 2007 >> Commander Overland, RWD >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P0325 To P0501 >> P0401-EGR System Performance >> Diagnostic Test
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Diagnostic Test

  1. 1) ACTIVE DTC 
    NOTE: Diagnose and repair any EGR circuit DTCs before continuing with this procedure.

    Turn the ignition on.

    With the scan tool, select View DTCs. Copy DTC and Freeze Frame information.

    Start the engine and allow it to reach operating temperature.

    WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.
    NOTE: Attempt to operate the vehicle under conditions similar to which the DTC was set.
    NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.

    With a scan tool, select View DTCs.

    Is the DTC Active or Pending at this time? 

    Yes 

    1. Go to  2).

    No 

    1. Refer to INTERMITTENT CONDITION Diagnostic Procedure.
  2. 2) ROUGH IDLE OR STALLING AT IDLE 

    Turn the ignition off.

    Turn all accessories off.

    Start the engine.

    WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

    Does the engine run rough or stall at idle? 

    Yes 

    1. Go to  3).

    No 

    1. Go to  5).
  3. 3) EGR VALVE ASSEMBLY CONTROL CIRCUIT 

    Turn the ignition off.

    Disconnect the EGR Valve Assembly harness connector.

    Start the engine.

    WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

    Does the engine continue to run rough or stall with the EGR Valve Assembly connector disconnected? 

    Yes 

    1. Go to  8).

    No 

    1. Go to  4).
  4. 4) (K35) EGR SOLENOID CONTROL CIRCUIT SHORTED TO VOLTAGE 
    Fig 1: Checking EGR Solenoid Control Circuit For Short To Voltage
    GC0014970Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the C2 PCM harness connector.

    Disconnect the EGR Solenoid harness connector.

    Ignition on, engine not running.

    Measure the voltage on the (K35) EGR Solenoid Control circuit in the EGR Solenoid connector.

    Is there any voltage present? 

    Yes 

    1. Repair the short to voltage in the (K35) EGR Solenoid Control circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  9).
  5. 5) EGR SYSTEM TEST 

    Turn all accessories off.

    Start the engine and allow it to reach operating temperature.

    WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

    With the scan tool, perform the EGR System Test.

    Select OPEN to open the EGR valve.

    Did the engine run rough or stall when the valve was opened during the system test? 

    Yes 

    1. Go to  8).

    No 

    1. Go to  6).
  6. 6) (Z42) EGR SOLENOID GROUND CIRCUIT OPEN 
    Fig 2: Checking EGR Solenoid Ground Circuit
    GC0014971Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Using a 12-volt test light connected to battery voltage, probe the (Z42) EGR Solenoid ground circuit in the EGR Solenoid harness connector.

    Does the 12-volt test light illuminate brightly? 

    Yes 

    1. Go to  7).

    No 

    1. Repair the open in the (Z42) EGR Solenoid ground circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  7. 7) (K35) EGR CONTROL CIRCUIT HIGH RESISTANCE 
    Fig 3: Checking EGR Solenoid Control Circuit For Open Or High Resistance
    GC0014973Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Connect the EGR Valve Assembly connector.

    CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 along with the #8815-1 to perform the diagnosis.

    Using a voltmeter, perform a voltage drop test by backprobing the (K35) EGR Control circuit at the EGR Valve Assembly harness connector and probing the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so that positive polarity is displayed on the voltmeter.

    Start the engine and allow it to reach operating temperature.

    WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

    With the scan tool, perform the EGR System Test.

    Select OPEN to open the EGR valve.

    Monitor the circuit voltage on the voltmeter.

    Is the voltage below 0.5 volts when the valve was opened during the system test? 

    Yes 

    1. Go to  8).

    No 

    1. Repair the (K35) EGR Control circuit for excessive resistance.
    2. Perform POWERTRAIN VERIFICATION TEST .
  8. 8) EGR VALVE ASSEMBLY 
    WARNING: The normal operating temperature of the EGR system is very high. Never work around or attempt to service any part of the EGR system until it has cooled.

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the EGR Valve Assembly and the Powertrain Control Module (PCM).

    Look for any chafed, pierced, pinched, or partially broken wires.

    Look for broken, bent, pushed out or corroded terminals.

    Verify that there is good pin to terminal contact in the EGR Solenoid and the Powertrain Control Module connectors.

    Refer to any Technical Service Bulletins that may apply.

    Inspect the EGR Valve Assembly for the following:

    - Proper mounting, leaking gasket(s)

    - Damaged, leaking, or obstructed EGR tube(s)

    - Carbon build up on or near the EGR pintle or within passages.

    Were any problem found? 

    Yes 

    1. Repair or replace the EGR system components as necessary.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Replace the EGR Valve Assembly.
    2. Perform POWERTRAIN VERIFICATION TEST .
  9. 9) POWERTRAIN CONTROL MODULE (PCM) 

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the EGR Solenoid Assembly and the Powertrain Control Module (PCM).

    Look for any chafed, pierced, pinched, or partially broken wires.

    Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Solenoid and the Powertrain Control Module connectors.

    Refer to any Technical Service Bulletins that may apply.

    Were there any problems found? 

    Yes 

    1. Repair as necessary.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Replace and program the Powertrain Control Module per Service Information.
    2. Perform POWERTRAIN VERIFICATION TEST .
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