FixVault

Diagnostic Test

  1. FUEL PUMP OPERATION 
    1. Ignition on, engine not running.
    2. With a scan tool, actuate the Fuel System test.
      NOTE: It may be necessary to use a mechanics stethoscope in the next step.
    3. Listen for fuel pump operation at the fuel tank.

      Does the Fuel Pump operate?

      Yes 

      • Go to step  2

      No 

      • Go to step  5
        CAUTION: Stop All Actuations.
  2. 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 Fuel Pressure Decay Tester 8978A at the engine.
    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).

      Choose a conclusion that best matches your fuel pressure reading.

      Below Specification 

      • Go to step  3

      Within Specification 

      • Test Complete.

      Above Specification 

  3. RESTRICTED FUEL SUPPLY LINE 
    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.
    1. Turn the ignition off.
    2. Disconnect the Fuel Pressure Decay Tester 8978A.
    3. Raise the vehicle on a hoist, and disconnect the fuel pressure line at the fuel pump module.
    4. Install the Fuel Pressure Decay Tester 8978A between the fuel supply line and the fuel pump module.
    5. Ignition on, engine not running.
    6. 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).

      Is the fuel pressure within specification now?

      Yes 

      No 

      • Go to step  4
        CAUTION: Stop All Actuations.
  4. CHECKING FUEL INLET STRAINER 
    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. Remove the Fuel Pump Module and inspect the Fuel Inlet Strainer.

      Is the Fuel Inlet Strainer plugged?

      Yes 

      No 

  5. (N1) FUEL PUMP RELAY OUTPUT CIRCUIT 
    Fig 1: Using 12-Volt Test Light Connected To Ground To Probe Fuel Pump Control Output Circuit At Fuel Pump Harness Connector
    GC0091124Courtesy of CHRYSLER LLC
    1. Turn the ignition off.
    2. Disconnect the TIPM C6 harness connector.
    3. Disconnect the Fuel Pump Module harness connector.
    4. Using a 12-volt test light connected to ground, probe the (N1) Fuel Pump Control Output circuit at the Fuel Pump harness connector.
      NOTE: Make sure the test light is probing the circuit before actuating the Fuel Pump or a DTC may set and not allow the actuation.
    5. With a scan tool, actuate the Fuel Pump Module.

      Does the test light illuminate brightly during the actuation?

      Yes 

      No