P0461
P0461-FUEL LEVEL SENSOR 1 PERFORMANCE
For a complete wiring diagram Refer to the Wiring Information.
Theory of Operation
The fuel level rationality will set a fault for a fuel level reading that does not change over an accumulated mileage threshold to keep stuck high or stuck low fuel levels from disabling OBD monitors. If the vehicle is fitted with a saddle tank fuel system this feature includes diagnostics for both of the sending units and diagnostics for a siphon tube that has become disconnected or plugged. The power up test looks to see a large enough fuel level voltage change from the last key-off to the following engine run. The engine run test looks to see a fuel level voltage change over an accumulated mileage.
- When Monitored:
TEST No.1: With the ignition on, the fuel level is compared to the previous key down after a 20 second delay. TEST No.2: The PCM monitors the fuel level at ignition on.
- Set Condition:
TEST No.1: If the PCM does not see a difference in fuel level of greater than 0.1 volt the test will fail. TEST No.2: If the PCM does not see a change in the fuel level of.1765 over a set amount of miles the test will fail. Two trip fault. Three good trips to turn off the MIL.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. ACTIVE DTC
NOTE: Diagnose any CAN - C or CAN - B Communication DTCs before continuing.
NOTE: Diagnose P0462 or P0463 first, if set along with P0461.
1. Start the engine.
2. Allow the engine to reach normal operating temperature.
3. With a scan tool, select View DTCs and record the related Freeze Frame data.
NOTE: It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the Freeze Frame data.
Is the DTC Active or Pending at this time?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. . Intermittent Condition Test
2. VISUALLY INSPECT FUEL TANK
1. Visually inspect the Fuel Tank for damage that may restrict the Fuel Sending Unit float from moving.
Is the Fuel Tank OK?
Yes
- Go To 3
No
- Replace the Fuel Tank as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
3. (N4) FUEL LEVEL SIGNAL CIRCUIT OPEN
1. Turn the ignition off.
2. Disconnect the Fuel Pump Module harness connector.
3. Disconnect the C7 TIPM harness connector.
4. Measure the resistance of the (N4) Fuel Level Signal circuit from the Fuel Pump Module harness connector to the TIPM harness connector.
Is the resistance below 5.0 ohms?
Yes
- Go To 4
No
- Repair the open in the (N4) Fuel Level Signal circuit.
- Perform BODY VERIFICATION TEST-VER 1. Body Verification Test
4. (N4) FUEL LEVEL SIGNAL CIRCUIT SHORTED TO GROUND
1. Measure the resistance between ground and the (N4) Fuel Level Signal circuit in the Fuel Pump Module harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the short to ground in the (N4) Fuel Level Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 5
5. (K91) SENSOR GROUND CIRCUIT OPEN
1. Disconnect the C1 TIPM harness connector.
2. Measure the resistance of the (K91) Sensor Ground circuit from the Fuel Pump Module harness connector to the C1 TIPM harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the open in the (K91) Sensor Ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 6
6. INTERNAL INSPECTION OF THE FUEL TANK
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. Remove the Fuel Tank.
2. Remove the Fuel Pump Module.
3. Visually inspect the inside of the Fuel Tank for any obstructions or deformities.
4. Inspect the Fuel Pump Module Float arm for damage.
Were any problems found?
Yes
- Repair or replace as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.
No
- Go To 7
7. FUEL LEVEL SENSOR
If there are no possible causes remaining, view repair.
Repair
- Verify that there is good pin to terminal contact at the Fuel Pump Module and the Powertrain Control Module connectors. Replace the Fuel Level Sensor if no problems were found at the connectors.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.