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Home >> Jeep >> 2024 >> Gladiator Nighthawk, Part Time T/Case Control, Standard Trans >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Communication Devices >> Body Control Module (BCM) - DTCS C1006-13 To U0155-00 >> DTC Troubleshooting >> P0460-15 Fuel Level Sensor 1 - Circuit Short To Battery Or Open >> Diagnostic Test

Diagnostic Test

  1. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN 
    1. With the scan tool, read DTCs in all Electronic Control Units (ECU'S) and record on the repair order.
    2. With the scan tool, run a vehicle Scan Report, or record the Environmental Data related to the DTCs.
    3. With the scan tool, erase all DTCs.
    4. Turn the ignition off for a minimum of 10.0 seconds.
    5. Turn the ignition on.
    6. Using the recorded Environmental Data and the When Monitored Conditions above, operate the vehicle in the conditions that set the DTC.
    7. With the scan tool, read Body Control Module (BCM) DTCs.

      Did the DTC return?

      Yes 

      • Go To  3

      No 

      • Go To  2
  2. MONITOR THE FUEL LEVEL SENSOR VOLTAGE READING FOR AN OPEN SPOT ON THE SENSOR 
    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. Disconnect the fuel supply line at the fuel rail.
    2. Connect a drain hose between the fuel supply line and an approved fuel container.
    3. Turn the ignition on.
    4. Remove the Fuel Pump Relay from the Power Distribution Center (PDC) Assembly.
      NOTE:

      When the Fuel Tank is completely empty, the Fuel Level Sensor should read at or near empty (indicated by a voltage reading of approximately 4.3-4.5 volts) on the scan tool. If the Fuel Tank is near full, the scan tool should read approximately 0.6 volts on the scan tool.

    5. Connect a jumper across Fuel Pump Relay terminal 30 and terminal 87 to actuate the Fuel Pump Assembly until all fuel is removed from the Fuel Tank.
    6. Remove the jumper when there is no more fuel coming out of the hose.
      NOTE:

      Make sure that you have enough fuel to put back into the vehicle to make a good determination of the Fuel Level Sensor voltage feedback. It may be necessary to add more fuel to what was removed in order to do so.

      NOTE:

      The Fuel Level Sensor voltage should decrease as fuel is added at a steady rate. Watch for the voltage to change suddenly while fuel is being added. If the voltage suddenly changes to or near 5.0 volts, it would indicate a bad spot (open) on that portion of the sensor.

    7. While monitoring the Fuel Level Sensor voltage reading on scan tool, begin putting fuel back into the Fuel Tank.

      Did the Fuel Level Sensor reading suddenly change to 5.0 volts at any time while adding fuel?

      Yes 

      • Replace the Fuel Level Sensor in accordance with the Service Information.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

  3. CHECK THE FUEL LEVEL SENSOR (N4) POSITION SIGNAL 1 CIRCUIT VOLTAGE 
    NOTE:

    The Fuel Pump Assembly harness connector must be connected when performing this step. The sensor is powered by a voltage close to the vehicle Battery (minus a diode voltage drop). If disconnected, the voltage reading on the Fuel Level Sensor Signal circuit will be equal to source voltage which is approximately Battery voltage.

    1. Back probe and measure the voltage on the Fuel Level Sensor (N4) Position Signal 1 circuit at the Fuel Pump Assembly harness connector.

      What is the voltage reading?

      Source voltage (approximately 12.0 volts): 

      • Go To  5

      Zero volts: 

      • Go To  4
  4. DISCONNECT THE FUEL PUMP MODULE AND BCM HARNESS CONNECTORS - CHECK THE (N4) FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR AN OPEN OR HIGH RESISTANCE 
    1. The ignition must be off when checking the resistance of a circuit.
    2. Disconnect all Electronic Control Unit (ECU) and component harness connectors containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
    4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
    5. Connect the other lead to the circuit being tested at the ECU harness connector and measure the resistance of the circuit.
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      Is the resistance above 3.0 Ohms?

      Yes 

      • Repair the circuit for an open or high resistance.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK THE VOLTAGE AT THE (G109) RETURN CIRCUIT 
    NOTE:

    The Fuel Pump Assembly harness connector must be connected when performing this step.

    1. Back probe and measure the voltage on the (G109) Return circuit at the Fuel Pump Assembly harness connector.

      What is the voltage reading?

      Source voltage (approximately 12.0 volts): 

      • Go To  7

      Zero volts: 

      • Go To  6
  6. DISCONNECT THE FUEL PUMP MODULE AND BCM HARNESS CONNECTORS - CHECK THE FUEL LEVEL SENSOR (N4) POSITION SIGNAL 1 CIRCUIT FOR A SHORT TO ANOTHER VOLTAGE SUPPLY CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect all Electronic Control Unit (ECU) and component harness connectors containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Connect the negative lead of the DVOM to the circuit being tested.
    4. Connect the positive lead of the DVOM to all other circuits at the ECU harness connector and check for continuity between the circuits.
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      NOTE:

      There should be no continuity between the circuits.

      Is there continuity between the circuit being tested and any other circuit?

      Yes 

      • Repair the circuit being tested for a short to the circuit that showed continuity.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

      • Replace the Fuel Level Sensor in accordance with the Service Information.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  7. DISCONNECT THE FUEL PUMP MODULE AND BCM HARNESS CONNECTORS - CHECK THE (G109) FUEL LEVEL SENSE RETURN CIRCUIT FOR AN OPEN OR HIGH RESISTANCE 
    1. The ignition must be off when checking the resistance of a circuit.
    2. Disconnect all Electronic Control Unit (ECU) and the component harness connectors containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
    4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
    5. Connect the other lead to the circuit being tested at the ECU harness connector and measure the resistance of the circuit.
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      Is the resistance above 3.0 Ohms?

      Yes 

      • Repair the circuit for an open or high resistance.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

      • Go To  8
  8. DISCONNECT RELATED BCM HARNESS CONNECTIONS AND INSPECT FOR PROBLEMS 
    1. Disconnect all BCM harness connectors.
    2. Disconnect all related in-line harness connections (if equipped).
    3. Disconnect the related component harness connectors.
    4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
      • Proper connector installation.
      • Damaged connector locks.
      • Corrosion.
      • Other signs of water intrusion.
      • Weather seal damage (if equipped).
      • Bent terminals.
      • Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
      • Terminals that have been pushed back into the connector cavity.
      • Perform a terminal drag test on each connector terminal to verify proper terminal tension.

      Repair any conditions that are found.

    5. Connect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. With the scan tool, erase DTCs.
    9. Using the recorded Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
    10. With the scan tool, read BCM DTCs.

      Did the DTC return?

      Yes 

      No 

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