Diagnostic Test

WARNING: This page is about a different car, the 2015 RAM 3500 HD and 2015 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FOR AN ACTIVE DTC
1. With the scan tool, read the Body Control Module (BCM) DTCs and record on the repair order.
  Is the DTC active?
  
  Yes
  - Go To 2
  No
  - The condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals and correct pin tension. If no problems are found, test complete.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE FUEL LEVEL SENSE VOLTAGE
1. With the scan tool, view the BCM Data Display.
2. Read the Fuel Level Sense voltage.
  Is the voltage greater than 5.1 volts?
  
  Yes
  - Go To 3
  No
  - Go To 8
CHECK THE RESISTANCE OF THE (G109) FUEL LEVEL SENSE RETURN CIRCUIT
1. Turn the ignition off.
2. Disconnect the Fuel Pump Module harness connector.
3. Measure the resistance between ground and the (G109) Fuel Level Sense Return circuit at the Fuel Pump Module harness connector.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Go To 5
CHECK THE (G109) FUEL LEVEL SENSE RETURN CIRCUIT FOR AN OPEN
1. Disconnect the BCM C5/E harness connector.
2. Measure the resistance of the (G109) Fuel Level Sense Return circuit between the BCM C5/E harness connector and the Fuel Pump Module harness connector.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open in the (G109) Fuel Level Sense Return circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 8
CHECK THE VOLTAGE OF THE (N4) FUEL LEVEL SENSOR SIGNAL CIRCUIT
1. Turn the ignition on.
2. Measure the voltage between the (G109) Fuel Level Sense Return circuit and (N4) Fuel Level Sensor Signal circuit at the Fuel Pump Module harness connector.
  Is there any voltage present?
  
  Yes
  - Go To 6
  No
  - Go To 7
CHECK FOR A SHORTED BCM WIRING HARNESS
1. Turn the ignition off.
2. Disconnect the BCM C5/E harness connector.
3. Check for continuity between the (N4) Fuel Level Sensor Signal circuit and every other pin in the BCM C5/E harness connector.
  Is the resistance above 3.0 Ohms for all connections?
  
  Yes
  - Go To 8
  No
  - Repair the short in the (N4) Fuel Level Sensor Signal circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
CHECK THE (N4) FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the BCM C5/E harness connector.
3. Measure the resistance of the (N4) Fuel Level Sensor Signal circuit between the Fuel Pump Module harness connector and the BCM C5/E harness connector.
  Is the resistance above 3.0 Ohms?
  
  Yes
  - Repair the open in the (N4) Fuel Level Sensor Signal circuit.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace the Fuel Level Sensor in accordance with the Service Information. Refer to SENDING UNIT AND SENSOR, FUEL LEVEL, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
BODY CONTROL MODULE (BCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Fuel Pump Module and the BCM.
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 Fuel Pump Module and the BCM harness connectors.
4. Perform any Technical Service Bulletins (TSB)s that may apply.
  Were any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL, REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .