What does it mean?
This generic powertrain/engine diagnostic code generally applies to all OBDII-equipped engines, but appears more frequently in certain Chrysler, GM, Ford, Lincoln, Mercury, Kia, Mazda, Mercedes Benz, Infiniti, Nissan, and Subaru vehicles.
The Fuel Level Sensor (FLS) is typically mounted inside the fuel tank, usually on top of the fuel tank module/fuel pump. The FLS converts the mechanical fuel level into an electrical signal for the Powertrain Control Module (PCM). Typically, the PCM will then inform other controllers using the vehicle’s data communication bus.
The PCM receives this voltage signal to determine the amount of fuel in the fuel tank, monitoring fuel usage and thus determining fuel economy. This code is set if this input does not match the normal operating voltages stored in the PCM’s memory, even for a second, as indicated by this diagnostic code. It also examines the voltage signal from the FLS sensor to determine if it is correct at initial key-on.
P0461 could have been set due to mechanical issues (incorrect fuel level rationality; refueling the vehicle with the ignition switch on or even with the engine running can cause this. The fuel level changes too rapidly, which is not normal) or electrical issues (FLS sensor circuit). These cannot be overlooked during the troubleshooting phase, especially when dealing with an intermittent problem.
Troubleshooting steps may vary depending on the manufacturer, the type of FLS sensor, and the wire colors.
Related fuel level sensor circuit trouble codes include:
P0460 Fuel Level Sensor Circuit Malfunction
P0462 Fuel Level Sensor Circuit Low Input
P0463 Fuel Level Sensor Circuit High Input
P0464 Fuel Level Sensor Circuit Intermittent
Severity and Symptoms
The severity depends on the failure. In case of mechanical failure; severe. In case of electrical failure, less severe, which the PCM can compensate for. Compensation usually means the fuel gauge reads empty or full all the time.
Symptoms of a P0461 engine code may include:
Malfunction Indicator Lamp (MIL) illuminated
Perceived decrease in fuel economy
Decreased distance to empty mileage
Incorrect fuel level on the gauge in the instrument cluster – always reads incorrectly
Potential Causes
Typically, the causes for this code to set are:
Open in the signal circuit to the FLS sensor – possible
Short to voltage in the signal circuit to the FLS sensor – possible
Short to ground in the signal circuit to the FLS sensor – possible
FLS sensor/sensing arm failing mechanically stuck – probable
PCM failed – unlikely
Diagnostic and Repair Procedures
A good starting point is always to search for a Technical Service Bulletin (TSB) for your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogram to cover this issue, and it is worth checking before discovering you’ve taken a long/wrong path.
A good example of this is on Ford products where an aftermarket remote start system was installed. This can cause a false code to be set. There is a TSB covering this topic and it should be followed to properly diagnose this condition. Auxiliary fuel tanks are also covered in this TSB. Gravity-fed tanks are not recommended for use on these systems and when refueling Ford trucks. It is recommended to refill the main tanks with the ignition switch in the off position.
Next, locate the Fuel Level Sensor (FLS) on your specific vehicle. This sensor is typically mounted inside the fuel tank or perhaps even on top of the fuel tank module/fuel pump. Once located, visually inspect the connector and wiring. Look for chafing, rubbing, bare wires, burns, or melted plastic. Disconnect the connector and carefully inspect the terminals (the metal parts) inside the connector. See if they look burnt or have a greenish tint indicating corrosion. Use electrical contact cleaner and a plastic bristle brush if cleaning the terminals is necessary. Let it dry and apply electrical grease where the terminals make contact.
If you have a scan tool, clear the diagnostic codes from memory and see if the P0461 code returns. If it does not, the connections were likely your problem.
This is the most common area of concern for this code, as fuel tank connections have the highest number of corrosion issues.
If the P0461 code returns, we will need to test the FLS sensor and its associated circuits. With the key off, disconnect the electrical connector from the FLS sensor. Connect a black wire from the Digital Volt Ohm Meter (DVOM) to the ground or low reference terminal at the FLS sensor wiring harness connector. Connect the red wire from the DVOM to the signal terminal at the FLS sensor wiring harness connector. Turn the key to the engine-off position. Check the manufacturer’s specifications; the voltmeter should read 12 volts or 5 volts. If the voltage is incorrect, repair the power or ground wire or replace the PCM.
If the previous test was successful, connect an ohmmeter to the signal terminal of the sensor and the other lead to the ground or low reference terminal of the sensor. The ohmmeter reading should not be zero ohms nor infinite. Check the manufacturer’s specifications for the sensor resistance to accurately test the resistance at the fuel level (1/2 tank of fuel might read 80 ohms). If the ohmmeter readings fail, replace the FLS.
If all previous tests were successful and you continue to get a P0461, this would most likely indicate a faulty FLS sensor, although a faulty PCM cannot be ruled out until the FLS sensor has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs need to be programmed or calibrated to the vehicle to be installed correctly.