P0461

DTC P0461 Fuel Level Sensor Circuit Low Voltage




Circuit Description
The fuel level sensor is an important input to powertrain control module (PCM) for the enhanced evaporative system diagnostic. Fuel level information is needed for the PCM to know the volume of fuel in the tank. The fuel level affects the rate of change in air pressure in the evaporative system. Several of the enhanced evaporative system diagnostic sub-tests are dependent upon correct fuel level information. The diagnostic will not run when the tank is greater than 85%, or less than 15% full. Fuel level DTCs should be diagnosed before other evaporative system DTCs because they can cause other DTCs to be set.
The sending unit is a float in the fuel tank which moves a wiper arm across a variable resistor. Low fuel level causes high resistance in the sending unit, and this is recognized by the PCM because the circuit operates at a corresponding low voltage. When the circuit is continuously open or has a high resistance connection, DTC P0462 is set.

Conditions for Setting the DTC
- Fuel tank level slosh test is completed.
- Fuel tank level main test is completed.
- Fuel tank level data is valid.
- Fuel tank level signal is less than a specified value.
- There are 100 test failures within a 200-test sample.

Action Taken When the DTC Sets
- The PCM will not turn the malfunction indicator lamp (MIL) ON.
- The PCM will store conditions which were present when the DTC was set as Failure Records only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the DTC
- The PCM will turn the MIL OFF after three consecutive trips without a fault condition present. A history DTC will be cleared if no fault conditions have been detected for 40 warm-up cycles (engine coolant temperature has risen 4 °C (40 °F) from the start-up ECT, and ECT exceeds 71 °C (160 °F) during that same ignition cycle).
- DTC P0462 can be cleared by using the scan tool Clear Into tunction or by disconnecting the PCM battery feed.

Diagnostic Aids
- Damaged harness-Inspect the wiring harness for damage. If the harness appears to be OK, observe the fuel level display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault.

Steps 1 - 6:

Steps 7 - 10:

Test Description
Number(s) below refer to the step number(s) on the Diagnostic Chart.
8. The following chart can be used to check the sending unit: