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Home >> Jeep >> 2021 >> Compass Trailhawk >> Repair and Diagnosis >> Engine Performance >> System >> 2.4L - DTCS P0197 To P0606 >> DTC Troubleshooting >> P0463-Fuel Level Sensor 1 Circuit High >> Diagnostic Test
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Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. Turn the ignition on.
    2. With the scan tool, read DTCs and record on the repair order.

      Is the DTC active or pending?

      Yes 

      • Go To  3

      No 

      • Go To  2
  2. MONITOR THE PRIMARY 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 PDC.
    5. Connect a jumper across terminal 30 and terminal 87 of the Fuel Pump Relay connector 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:

      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 0.5 volts on the scan tool.

      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.

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

      The Primary 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.

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

      Yes 

      No 

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

    Do not disconnect the Fuel Pump Assembly harness connector during this step. The primary 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 (N4) Fuel Level Sensor Signal 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. CHECK THE (N4) FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the Fuel Pump Assembly harness connector.
    3. Disconnect the BCM C6 harness connector.
    4. Measure the resistance of the (N4) Fuel Level Sensor Signal circuit between the Fuel Pump Assembly harness connector and the BCM C6 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  8

      No 

      • Repair the (N4) Fuel Level Sensor Signal circuit for an open circuit.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  5. CHECK THE VOLTAGE AT THE (G109) FUEL LEVEL SENSE RETURN CIRCUIT 
    NOTE:

    Leave the Fuel Pump Assembly harness connector plugged in during this step also.

    1. Back probe and measure the voltage on the (G109) Fuel Level Sense 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. CHECK THE (N4) FUEL LEVEL SENSOR SIGNAL CIRCUIT FOR A SHORT TO ANOTHER VOLTAGE SUPPLY 
    1. Turn the ignition off.
    2. Disconnect the Fuel Pump Assembly harness connector.
    3. Disconnect the BCM C6 harness connector.
    4. Check for continuity between the (N4) Fuel Level Sensor Signal circuit and all other circuits at the BCM C6 harness connector.

      Is there continuity between the (N4) Fuel Level Sensor Signal circuit and any other circuit?

      Yes 

      • Repair the (N4) Fuel Level Sensor Signal circuit for a short to the circuit that showed continuity.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

  7. CHECK THE (G109) FUEL LEVEL SENSE RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (G109) Fuel Level Sense Return circuit between the Fuel Pump Assembly harness connector and the BCM C6 harness connector.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  8

      No 

      • Repair the (G109) Fuel Level Sense Return circuit for an open or high resistance.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  8. CHECK RELATED BCM AND COMPONENT CONNECTIONS 
    1. Perform any Service Bulletins that apply.
    2. Disconnect all BCM harness connectors.
    3. Disconnect all related in-line harness connections (if equipped).
    4. Disconnect the related component harness connectors.
    5. 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.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    6. Reconnect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    9. With the scan tool, erase DTCs.
    10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    11. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No 

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