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Home >> Chrysler >> 2011 >> 300 C, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 428 (5.7L - DTCS P2317 To U148C - 2500 Hd & 3500 Hd) >> Diagnosis And Testing >> U0109-Lost Communication With Fuel Pump Control Module >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2013 RAM 3500 HD and 2013 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
  1. ACTIVE DTC 
    1. Turn the ignition on, engine not running.
    2. With the scan tool, read DTCs.

      Is the DTC active?

      Yes 

      • Go To  2

      No 

  2. CHECK THE (N12) FPCM FEEDBACK RETURN CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Leave the ignition on, engine not running.
    2. Disconnect the FPCM harness connector.
    3. Measure the voltage of the (N11) Control circuit at the FPCM harness connector.

      Does the voltage measure above 5.2 volts?

      Yes 

      • Repair the (N12) FPCM Feedback Return circuit for a short to voltage.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  3
  3. CHECK THE (N12) FPCM FEEDBACK RETURN CIRCUIT FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect the PCM C1 harness connector.
    3. Measure the resistance between ground and the (N12) FPCM Feedback Return circuit at the FPCM harness connector.

      Is the resistance above 10k ohms?

      Yes 

      • Go To  4

      No 

      • Repair the (N12) FPCM Feedback Return circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  4. CHECK THE (N12) FPCM FEEDBACK RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Leave the ignition off.
    2. Measure the resistance of the (N12) FPCM Feedback Return circuit between the FPCM harness connector and the PCM C1 harness connector.

      Is the resistance below 5.0 ohms?

      Yes 

      • Replace the Fuel Pump Control Module (FPCM) in accordance with the service information.
      • Go To  5

      No 

      • Repair the (N12) FPCM Feedback Return circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  5. POWERTRAIN CONTROL MODULE 
    1. Let the engine run until it reaches normal operating temperature.
    2. Using the scan tool, record any DTCs.

      Did the DTC return?

      Yes 

      • Replace the Powertrain Control Module in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Repair is complete.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
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