Diagnostic Test

1. Start the engine.
2. Allow the engine to reach normal operating temperature.
3. With the 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  2

   No 

   • Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .

Are the U110F or U1411 DTCs present in the PCM?

Yes 

• Diagnose and repair those DTCs.
• Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

No 

• Go To  3

Are any Fuel Level Sensor Circuit DTCs set in the BCM?

Yes 

• Diagnose the appropriate Fuel Level Sensor Circuit DTC in the BCM. Refer to BODY CONTROL MODULE (BCM) - DIAGNOSTIC CODE INDEX - 2500 HD & 3500 HD article .

No 

• Go To  4

1. Visually inspect the Fuel Tank for damage that may restrict the Fuel Sending Unit float from moving.

   Is the Fuel Tank OK?

   Yes 

   • Go To  5

   No 

   • Replace the Fuel Tank as necessary.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

1. Turn the ignition off.
2. Disconnect the Fuel Tank Assembly in-line harness connector.
3. Disconnect the PCM C2 harness 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 the GPEC Diagnostic Adaptor to perform the diagnosis.

4. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
5. Measure the resistance of the (N5) Fuel Level Signal 2 circuit between the Fuel Tank Assembly in-line harness connector and the GPEC Adaptor.

   Is the resistance below 5.0 Ohms?

   Yes 

   • Go To  6

   No 

   • Repair the (N5) Fuel Level Signal 2 circuit for an open or high resistance.
   • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

1. Measure the resistance of the (G109) Fuel Level Signal Sense Return circuit between the Fuel Tank Assembly in-line harness connector and the GPEC Adaptor.

   Is the resistance below 5.0 Ohms?

   Yes 

   • Go To  7

   No 

   • Repair the (G109) Fuel Level Signal Sense Return circuit for an open or high resistance.
   • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

1. Reconnect the PCM C2 harness connector.
2. Visually inspect the Fuel Tank Assembly harness for any signs of damage which could cause an open or shorted circuit.
3. Remove the Fuel Pump Module.
4. Visually inspect the inside of the Fuel Tank for any obstructions or deformities.
5. Inspect the Fuel Pump Module Float arm for damage.

   Were any problems found?

   Yes 

   • Repair or replace as necessary.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

   No 

   • Go To  8

1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Body Control Module (BCM) and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Sensor and Powertrain Control Module connectors.
4. Perform any Technical Service Bulletins that may apply.

   Were there any problems found?

   Yes 

   • Repair as necessary.
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

   No 

   • Replace and program the Powertrain Control Module in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL . Refer to PCM/ECM REPROGRAMMING - GAS .
   • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .