P0461

P0461-FUEL LEVEL SENSOR 1 PERFORMANCE




For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.
Theory of Operation

The fuel level sending unit is attached to the side of the fuel pump module.The sending unit consists of a float, an arm and a variable resistor track (card). The fuel transfer pump is also attached to the fuel pump module. A constant 5-volt signal is supplied to the resistor track of the fuel gauge sending unit. The resistor track is a variable resistor used to vary the voltage signal depending on fuel tank float position. As fuel level increases, the float and arm move up, which decreases voltage. As fuel level decreases, the float and arm move down which increases voltage. When the fuel tank level is measured below 15%, the following fuel system monitors are shut off: P0191 (Fuel Pressure Idle Diagnostic portion of it), and DTCs P0300, P0301, P0302, P0303, P0304, P0305, P0306. The CCN will illuminate the MIL lamp immediately after this diagnostic runs and fails. The CCN will turn off the MIL lamp after the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:
While the engine is running.

- Set Condition:
Fuel level does not change by a calibrated amount over a calibrated amount of time.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. EXTERNAL DAMAGE TO FUEL TANK
1. Visually inspect the fuel tank for external damage.

Is the fuel tank damaged from the outside?

Yes

- Replace the fuel tank.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 2

2. FUEL LEVEL SENSOR SIGNAL CIRCUIT OPEN/HIGH RESISTANCE




1. Turn ignition off.
2. Disconnect the Fuel Pump Module harness connector.
3. Disconnect the CCN C4 harness connector.
4. Measure the resistance of the (N4) Fuel Level Sensor Signal circuit between the CCN C4 harness connector and the Fuel Level Sensor harness connector.

Is the resistance less than 5.0 Ohms?

Yes

- Go To 3

No

- Repair the open or high resistance in the (N4) Fuel Level Sensor Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

3. FUEL LEVEL SENSOR RETURN CIRCUIT OPEN/HIGH RESISTANCE




1. Turn the ignition off.
2. Disconnect the CCN C3 harness connector.
3. Measure the resistance of the (Z210) Fuel Level Sensor Return circuit between the CCN C3 harness connector and the Fuel Pump Module harness connector.

Is the resistance less than 5.0 Ohms?

Yes

- Go To 4

No

- Repair the open or high resistance in the (Z210) Fuel Level Sensor Return circuit.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

4. FUEL LEVEL SENSOR
1. Remove the Fuel Level Sensor from the fuel tank.

Does the fuel level float arm move freely?

Yes

- Go To 5

No

- Replace the Fuel Level Sensor.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

5. FUEL LEVEL SENSOR
1. Measure the resistance across the (N4) Fuel Level Sensor Signal circuit and (Z210) Fuel Level Sensor Return circuit at the Fuel Level Sensor while moving the sensor float arm up and down.

Does the resistance read between approximately 20 and 220 Ohms as you move the sensor arm?

Yes

- Go To 6

No

- Replace the Fuel Level Sensor.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

6. INSIDE OF FUEL TANK OBSTRUCTED DAMAGED
1. Visually inspect the inside of the fuel tank for obstructions.

Is the inside of the fuel tank damaged or obstructing the Fuel Level Sensor?

Yes

- Replace the fuel tank.
- Perform POWERTRAIN VERIFICATION TEST - 6.7L). Powertrain Verification Test.

No

- Test Complete.