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HOMESERVICE MANUALSJEEP2009GRAND CHEROKEE LAREDO, 3.0 M, AWDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 9 (DTCS P0125 TO P0196 - GAS)P0174-FUEL SYSTEM 2/1 LEANDIAGNOSTIC TEST
2009 Jeep Grand Cherokee Laredo, 3.0 M, AWD

Diagnostic Test

2009 Jeep Grand Cherokee Laredo, 3.0 M, AWDSECTION Diagnostic Test
WARNING: This page is about a different variant/trim than selected.
  1. ACTIVE DTC 
    NOTE: Check for contaminants that may have damaged an O2 Sensor: contaminated fuel, unapproved silicone, oil and coolant.
    1. Diagnose all other trouble codes before continuing.
    2. Start the engine.
    3. Allow the engine to reach normal operating temperature.
    4. With a scan tool, select View DTCs.
      NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.

      Is the DTC Active or Pending at this time?

      Yes 

      • Go to step  2

      No 

  2. CHECKING FUEL PRESSURE 
    WARNING: The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.
    1. Turn the ignition off.
    2. Install a fuel pressure gauge to the fuel rail.
    3. Ignition on, engine not running.
    4. With the scan tool, actuate the ASD Fuel System test and observe the fuel pressure gauge.
      NOTE: Fuel pressure specification is 407 kPa +/- 34 kPa (59 psi +/- 5 psi).
    5. Turn the ignition off.

      Choose a conclusion that best matches your fuel pressure reading.

      Within Specification 

      • Go to step  3

      Above Specification 

      Below Specification 

      • Go to step  13
        CAUTION: Before Proceeding Stop All Actuations.
  3. CHECKING THE EXHAUST SYSTEM FOR LEAKS 
    1. Turn the ignition off.
    2. Raise the vehicle in accordance with the Service Information.
      WARNING: The normal operating temperature of the exhaust system is very high. Never work around or attempt to service any part of the exhaust system until it has cooled. Special care should be taken when working near the catalytic converter. The temperature of the converter rises to a high level after a short period of engine operating time
    3. Connect Exhaust Cone #8404-EC or #8404-EC to Air Pressure Regulator (with hose) #W-18-MIL-1146AS.
      CAUTION: The air pressure must not exceed 27.6 kPa (4 psi), otherwise engine damage can occur.
    4. Attach shop air to the air pressure regulator.
    5. Adjust the Air Pressure Regulator to 27.6 kPa (4 psi)
    6. Insert the exhaust cone into the vehicle tail pipe.
    7. If the vehicle is equipped with dual exhaust. Use the #8404-ECT with equipped attached plug, plug one side of the dual exhaust pipe. Pressurize the other as described above.
    8. Apply Mopar® Air Leak Detector PN# 05191804AA (or an equivalent leak finder liquid) to the following areas:
      • All welded joints from the exhaust manifold to 152.4 mm (6 inches) behind the downstream O2 sensor
      • O2 sensor seal points
      • O2 sensor boss welds
      • Flange/joint connection(s)
      • Exhaust manifold to cylinder head connection(s)
      • EGR solenoid gasket base and tube seal points (if equipped)
    9. Watch for the liquid/soapy water to bubble.
    10. Use the following definitions to help determine if system or component repair/replacement is necessary:

      Type 1 Leak  is defined as a leak where very small foam like bubbles 1 mm (0.04 of an inch) or less appear.

      Any Type 1 or greater leaks found in welded joints, O2 sensor seal points or O2 sensor boss welds must be repaired or the component must be replaced.

      Type 2 Leak  is defined as a leak where larger bubbles pea size, 8 mm (0.3 of an inch) or greater appear.

      Any Type 2 or greater leaks found in flange or joint connections, exhaust manifold to cylinder head connections, or EGR gasket and tube seal points must be repaired or the components must be replaced

      Leak Location  Repair required if results at 27.6 kPa (4 psi) reveal bubble size: 
      Welded joints Type 1, 1 mm (0.04 of an inch) or greater
      O2 Sensor seal points Type 1, 1 mm (0.04 of an inch) or greater
      O2 Sensor boss welds Type 1, 1 mm (0.04 of an inch) or greater
      Flange/joint connections Type 2, 8 mm (0.3 of an inch) or greater
      Exhaust Manifold to cylinder head connections Type 2, 8 mm (0.3 of an inch) or greater
      EGR gasket and tube seal points Type 2, 8 mm (0.3 of an inch) or greater
    11. If a leak is found that matches the above definition, repair or replace the component as necessary.
    12. Once the repair is complete, repeat the procedure to verify that all leaks have been repaired.

      Were any exhaust leaks found?

      Yes 

      No 

      • Go to step  4
  4. O2 SENSOR OPERATION 
    1. Start the engine.
    2. Allow the engine to reach normal operating temperature.
      NOTE: If one of the O2 Sensor's Signal or Return circuit is shorted to ground the scan tool will display all O2 Sensor voltage readings low. The O2 Sensor that is shorted to ground will display a voltage reading near or at 0 volts.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.