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Error Code P0464 is defined as Fuel Level Sensor Circuit Intermittent.
This code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II, especially those made from 1996 up to the present day. Anecdotally, it seems more common among Ford and Subaru vehicle models. Specifications on the definition, troubleshooting, and repairs, of course, vary from one make and model to another.
The fuel level sensor (also known as sender) is an essential component of the fuel pump module and located in the fuel tank. This component can’t be replaced without replacing the pump module, though there are some exceptions. Attached to the arm is a float that travels with a resistor grounded to the tank, frame or a dedicated ground circuit. The sender receives a supplied voltage, and the ground path changes according to the level of fuel. The amount of voltage depends on the system, but in many times it’s around 5V.
As the fuel level changes, the float moves the arm, changing the resistance to ground which varies the voltage signal. This signal will either go straight to the fuel pump computer module, or to the instrument cluster module. Depending on the vehicle’s system, the fuel pump computer module may only monitor the resistance to ground, and then relay the fuel level information to the instrument panel.
Error Code P0464 may be set due to mechanical issues, such as incorrect fuel level rationality, refueling the vehicle with ignition switched “On”, or even engine running can cause this problem. Fuel changed rapidly which is NOT normal, or electrical (FLS sensor circuit) problems can also cause this code. Thus, when diagnosing for intermittent problem, these factors can’t be overlooked.
Other related Error Codes include:
- P0460 Fuel Level Sensor Circuit Malfunction
- P0461 Fuel Level Sensor Circuit Range/Performance
- P0462 Fuel Level Sensor Circuit Low Input
- P0463 Fuel Level Sensor Circuit High Input
As with other error codes, this code activates the Check Engine light as its first symptom.
Common symptoms include:
- Incorrect fuel level on gauge in instrument cluster – always reads wrong
- Erratic fuel gauge
- Decrease in perceived fuel economy
- Decrease in distance to Empty mileage
Also, the severity of the symptoms depends upon the failure. Mechanical failure means severe symptoms, while electrical failure is not as severe as the PCM can compensate for it. Compensation usually means the fuel gauge reads Empty of Full all the time.
Common causes for this code include:
- Open in the signal circuit to the FLS sensor
- Damaged fuel tank
- Fuel level sensor has suffered an opening
- Open ground circuit
- Rusty ground path causing high resistance
- Short of voltage in the signal circuit to the FLS sensor
- Short to ground in the signal circuit to the FLS sensor
- Failed FLS Sensor/sensing arm stuck mechanically
- Failed PCM (rare)
How to Check
Error Code P0462 is quite a simple problem, and as with other Error Codes, diagnosis for this code starts with the use of OBD-II scanner; mechanics look for codes that have been logged in the vehicle’s PCM.
Technicians will also check the tank from the outside and look for signs of damage that could be leading to poor readings.
Given that this code is a voltage problem, technicians will inspect the circuitry related to the fuel level sensor responsible for sending wrong readings to the PCM.
Lastly, technicians will test the sensor itself.
Also, the steps for diagnosing this code may vary depending upon manufacturer, type of FLS sensor and wire colors.
How to Fix
Common repairs for this code include:
- Sealing of the fuel tank, or replacement
- Replacement of the entire fuel level sensor or malfunctioning element
- Replacement of broken or frayed wires
If after all the prior tests you continue to get the Error Code P0464, then there’s a good chance a failed FLS sensor may cause the fault. Though you can’t also rule out a failed PCM condition, you still need to check out the FLS sensor first and must be replaced. If unsure, make sure you seek assistance from a trained technician. The PCM must be programmed and calibrated to the vehicle to work correctly