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Home >> Jeep >> 2021 >> Gladiator Mojave, Part Time T/Case Control, Standard Trans >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> 3.6L (GPEC 2A) - DTCS P0330 To P0480 >> DTC Troubleshooting >> P0463-Fuel Level Sensor 1 Circuit High >> Fuel Level Sensor Rationality Diagnostics (P0461, P2066)

Fuel Level Sensor Rationality Diagnostics (P0461, P2066)

Excessive pressure build up or vacuum in the Evaporative system could possibly contribute to this DTC being set. Diagnose and repair any Evaporative System DTCs before continuing with this fault.

SINGLE TANK FUEL LEVEL SENSOR RATIONALITY DIAGNOSTICS: 

  1. Visually inspect the Fuel Tank for any obvious physical damage that may restrict the Fuel Level Sensor float from moving. If the Fuel Tank is damaged, replace the tank assembly. If the Fuel Tank has no visible damage, and there are no circuit faults present, the rationality fault is most likely due to an intermittent connection, obstructed float arm, bad spot on the Fuel Level Sensor resistor card, or faulty BCM. Continue to step 2.
  2. Verify that the Fuel Pump connector is properly connected and locked. Check the Fuel Pump and BCM harness connectors and terminals for pushed out, spread, corroded or dirty terminals. If the connector or terminals appear damaged, repair or replace the damaged connector or terminals.
  3. Check the ability of the BCM to read the Fuel Level Sensor signal correctly. Disconnect the Fuel Pump harness connector. Connect the (special tool #2064100080, Kit, Electrical Test Lead)
    GC0184425Courtesy of CHRYSLER GROUP, LLC

    to the Fuel Level Signal and Return Signal circuits at the Fuel Pump harness connector. Turn the ignition on. Move the switch on the Electrical Test Lead Kit to the adjust position. For most Fuel Level Sensors, the typical resistance on the resistor card is between approximately 50 Ohms (Full Stop) and 1000 Ohms (Empty Stop). Turn the ignition on and monitor the signal voltage on the scan tool, while varying the resistance on the Electrical Test Lead Kit between approximately 50 and 1000 Ohms.

    1. If the signal voltage is changing between 0.0 volts and 5.0 volts while changing the resistance  - the BCM is reading the Fuel Level Sensor signal correctly. The Fuel Level Sensor is most likely faulty or has a poor connection at the harness connector. Check the Fuel Pump harness connector for pushed out, spread, corroded or dirty terminals before condemning the sensor. If the terminals and connector check good, replace the faulty Fuel Level Sensor.
    2. If the signal voltage is not changing between 0.0 volts and 5.0 volts while changing the resistance  - use the wiring information to check all related harness connectors for pushed out, spread, corroded or dirty terminals. If no issues are found, check the Fuel Level Sensor Signal and Return Signal circuits for high resistance (refer to the appropriate circuit fault information for additional assistance on testing the circuits). If the circuits test good, the BCM is faulty.

SADDLE TANK FUEL LEVEL SENSOR RATIONALITY DIAGNOSTICS:  Before starting it is important to note that in a properly operating system the primary side of the tank should always be at or very close to full if there is fuel in the secondary side of the tank. Therefore, the primary level sensor rationality fault should only set if the secondary side is empty and the primary level sensor is not changing as fuel is consumed. The secondary level sensor rationality fault should only set if the primary side is full and the secondary level sensor is not changing as fuel is consumed. It is possible for a secondary Fuel Level Sensor to be stuck in the empty position causing a primary Fuel Level Sensor rationality fault. Therefore, a good practice is to look at, and compare both level sensor values when diagnosing either rationality DTC to verify which sensor to diagnose.

  1. Visually inspect the Fuel Tank for any obvious physical damage that may restrict either Fuel Level Sensor float from moving. If the Fuel Tank is damaged, replace the tank assembly. If the Fuel Tank has no visible damage, and there are no circuit faults present, the rationality fault is most likely due to an intermittent connection, obstructed float arm, bad spot on the Fuel Level Sensor resistor card, or faulty BCM. Continue to step 2.
  2. Using the scan tool check for any Evaporative System or Fuel Level Sensor circuit faults.
    1. Diagnose and repair any Evaporative System DTCs before continuing with this fault.
    2. Diagnose any Fuel Level Sensor circuit faults before continuing with the rationality diagnostic.
      • If no other faults are present, continue to step 3.
  3. This step is designed to try and determine which sensor is giving a false reading. Using the scan tool, read the voltage for both Fuel Level Sensors in the BCM data. This step may require adding or removing fuel in the tank in order to make a decision as to which level sensor to diagnose. NOTE: A normally functioning level sensor will typically read between approximately 4.3 - 4.5 volts at empty and 0.5 - 0.65 volts at full. 
    1. If the primary side of the tank is reading less than full and the secondary side of the tank is reading empty, Go to step 4.
    2. If the primary side of the tank is reading less than full, but the secondary side of the tank is showing fuel present, Go to step 4.
    3. If the primary side of the tank is reading full and the secondary side of the tank is reading empty, Go to step 4.
    4. If the primary side of the tank is reading full and the secondary side of the tank is showing fuel present, Go to step 5.
  4. Add the amount of fuel to the tank that it takes to fill the primary side to guarantee that there is overflow to the secondary side of the Fuel Tank. Using the scan tool, read the voltage for both Fuel Level Sensors in the BCM data. The primary level sensor should read full and the secondary level sensor should show some fuel present. Follow the scenario that best fits below:
    1. If the primary side is not reading full, diagnose the primary level sensor in step 6 below.
    2. If the secondary side is not showing any fuel present, diagnose the secondary level sensor in step 6 below.
    3. If both sensors appear to be reading normal, start removing fuel from the tank into an approved storage container. The secondary level sensor should decrease to empty before the primary starts decreasing. If the primary level sensor starts decreasing before the secondary side starts moving diagnose the secondary level sensor in step 6 below.
  5. Start removing fuel from the tank into an approved storage container. Remove enough fuel to guarantee the total Fuel Tank level is below 1/2 tank.
    1. If the primary side of the tank is reading full and the secondary side of the tank is reading empty, diagnose the primary level sensor in step 6 below.
    2. If the primary side of the tank is reading less than full but the secondary side of the tank is showing fuel present, diagnose the secondary level sensor in step 6 below.
  6. Perform the following diagnostics on the Fuel Level Sensor that was not reading rational in step 4 or 5.  Verify that the harness connector at the Fuel Pump or Auxiliary Fuel Pump/Level Sensor is properly connected and locked. Check the Fuel Pump, Auxiliary Fuel Pump/Level Sensor and BCM harness connectors and terminals for pushed out, spread, corroded or dirty terminals. If the connector or terminals appear damaged, repair or replace the damaged connector or terminals.
  7. Check the ability of the BCM to read the Fuel Level Sensor signal correctly. Disconnect the appropriate harness connector. Connect the (special tool #2064100080, Kit, Electrical Test Lead)
    GC0184425Courtesy of CHRYSLER GROUP, LLC

    to the Fuel Level Signal and Return Signal circuits in the harness connector. Move the switch on the Electrical Test Lead Kit to the adjust position. For most Fuel Level Sensors, the typical resistance on the resistor card is between approximately 50 Ohms (Full Stop) and 1000 Ohms (Empty Stop). Turn the ignition on and monitor the signal voltage on the scan tool, while varying the resistance on the Electrical Test Lead Kit between approximately 50 and 1000 Ohms.

    1. If the signal voltage is changing between 0.0 volts and 5.0 volts while changing the resistance  - the BCM is reading the Fuel Level Sensor signal correctly. The Fuel Level Sensor is most likely faulty or has a poor connection at the harness connector. If the issue is with the secondary side showing fuel when the primary is less than full  this issue could be caused by the fuel not being pulled over from the secondary side to the primary side of the Fuel Tank due to a damaged or faulty siphon tube or Auxiliary Pump. Remove the Auxiliary Pump assembly and check for fuel stuck on the secondary side. If the secondary side is empty, replace the faulty Fuel Level Sensor. If the secondary side still has fuel when the primary side is less than full, examine and repair or replace the Auxiliary Pump or siphon tube assembly.
    2. If the signal voltage is not changing between 0.0 volts and 5.0 volts while changing the resistance  - check the Fuel Level Sensor Signal and Return circuits for high resistance (refer to the appropriate circuit fault information for additional assistance on testing the circuits). If the circuits test good, use the wiring information to check all related harness connectors for pushed out, spread, corroded or dirty terminals that can cause an intermittent open before condemning BCM. If no issues are found, the BCM is faulty.
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