Fuel level sensor is one of the most practical sensors in any car, at least when it comes to how much an average driver relies on it. Without a functioning fuel level sensor, you won’t have accurate information on how much fuel you’ve got left in your car. Unfortunately, these sensors fail from time to time and when they do, you’ll usually get a check engine light code.
Today we’ll look at one of those codes, specifically the P0461. Being a non-critical code by nature, many people will ignore it as it isn’t an engine issue. However, it can still cause a fair bit of trouble in other ways, such as leaving you stranded on the side of the road because you ran out of fuel.
We will delve deep into the causes, symptoms, and diagnosis methods that you can use for this trouble code. All in the name of DIY repair.
What is the P0461 Code, and What Does It Mean?
A P0461 code returns the following error “Fuel Level Sensor “A” Circuit Range/Performance.” This error is stored when there is a difference between the fuel gauge reading and the actual gas in the tank. The PCM uses a reference voltage for where the fuel gauge should be and compares it to the fuel sensor voltage. If the two aren’t matching, the PCM will trigger the code.
How Does the Fuel Level Sensor Work?
The fuel level sensor works by utilizing 3 components located in the fuel tank. We’re talking about the float, the actuating arm and the resistor. All three of these components are usually a part of the fuel pump sender unit, which is an assembly that houses the in-tank fuel pump and other goodies.
Here’s how this system works. The float component is buoyant, hence the name. It is connected to the resistor via the actuating arm. When you pour fuel into the tank, the float rises with the fuel level, changing the angle of the actuating arm. The arm changes the values of the grounded actuating resistor as it moves up and down, which in turn sends a signal to your fuel gauge.
Where is the Fuel Level Sensor Located?
The fuel level sensor is at the top of the fuel tank, attached to the fuel pump sender unit. To access the fuel level sensor, you’ll need to gain access to the fuel tank.
On many cars this is possible by uncovering the fuel tank port somewhere in the trunk or under the rear seat. However, there are instances where you’ll need to drop the fuel tank to access these components.
What Causes the P0461 Code?
Fuel level sensors should last as long as the vehicle, or at least that’s the general idea. Like any part, though, the sensor or related components can fail. Some of the common failure points are:
- Fuel level sensor failure
- Circuit damage
- Fuel tank damage
- PCM failure
Fuel Level Sensor Failure
The sensor is the key component when it comes to measuring how much fuel is in your tank. There is no other related part that performs the same function, making it the most likely culprit when it comes to this particular code. Failure means that you will get an inaccurate reading in your instrument cluster and the P0461 code.
Circuit Damage
Of course, the circuit that connects the fuel sensor and fuel gauge can fail. This includes the wiring harness, connectors, and all the components along the circuit. Usually, it will cause additional codes, so be on the lookout for those.
Furthermore, include a proper fuse inspection when looking into any wiring issues or potential shorts. This is a common cause when having issues with the instrument cluster side of things in particular.
Fuel Tank Damage
Car accidents or any other form of severe kinetic damage to the rear of the car can cause the sensor to malfunction.
The cause of the malfunction can be actual damage to the fuel level sending unit, or damage to the fuel tank that results in a mechanical obstruction of the fuel sensor float. As rare as such instances are, they do happen from time to time. This is especially true if your car was involved in an accident in the past.
PCM Failure
Although this is rare and, in most cases, a factory software issue, it can still occur during your vehicle ownership. There will certainly be a host of trouble codes when this issue arises, so it’s unlikely that this is the issue if you only have a P0461.
What Are the Common Symptoms of P0461 Fault Code?
As this is a specific system issue that does not affect any other system, there are not many symptoms. We can narrow them down to two common ones that will point to a P0461 trouble code. These are:
- Check Engine Light
- Malfunctioning fuel gauge
Check Engine Light
Manufacturers design the fuel system to be sensitive to voltage changes. The sensitivity has a downside, however, as false positives can lead to a check engine light, which can raise unnecessary alarm bells.
That being said, in the case of P0461, the check engine light is almost always triggered by an actual issue, especially if it’s a current code. History codes or intermittent codes change things to a degree as they are often caused by intermittent shorts somewhere within the system.
Malfunctioning Fuel Gauge
This is a telltale sign that there is an issue with the fuel level sensor circuit. An incorrect reading, fluctuations, or the fuel remaining at the same level point to a faulty or failing fuel level sensor.
Keep in mind that once the fuel gauge begins to deviate from the actual values, you can’t really trust it anymore until the issue is rectified. To avoid being stuck on the side of the road somewhere, try to keep your gas tank near full at all times.
How to Diagnose and Fix the Cause of P0461 Code
You would think that since this problem is relegated to the fuel system, it would be easy to diagnose and fix. Unfortunately, this is not the case, as some causes lie in hard-to-reach places like the instrument cluster. However, it is not impossible to figure out the P0461 code. Here’s how we suggest going about doing this.
OBD II Reader
Whenever you see a check engine light on the dash, the very first step towards diagnosing the issue should be to run a full scan of the car’s systems using an OBD II reader. The OBD II reader will tell you exactly what codes you’re dealing with and how quickly you should begin addressing each of the issues found. It is still possible to diagnose and fix this issue without it, but the availability and price of these scan tools make them a great option.
The OBD port is often found on the passenger side, below the glove box. That being said, the location of the OBD port tends to differ from vehicle to vehicle, so it’s a good idea to consult your car’s manual for more information.
Once you run the scan and see a P0461 in the error log, you can proceed to do a self-test of the system, it should run the fuel gauge and move the needle around. That will tell you whether the gauge is functioning properly.
Check the Fuses
This is also one of the common external causes of this error code. Fuses either work or they don’t. If a fuse is blown, it will completely sever the circuit it is on. They do this by blowing and breaking the circuit when too much current flows through them.
Any burn marks indicate the fuse has blown and needs replacing. When you replace the fuse, ensure that you use one of the same amperage, rating, and type. This will ensure that in the event of another failure, it will protect your components.
Wiring Harness Failure
Wire damage is a common cause of sensor issues. Rodents often chew wires, or the rubber sheath cracks due to age. By looking for any breaks or damage to the circuit, we can ensure that there is no external damage. This does not mean that there is not an internal short, so to test that, we will need a multimeter.
First, ensure that your vehicle is off. This will prevent any electrical current from flowing through the circuit. Disconnect the harness connector from the fuel sensor.
Once that is completed, put your vehicle in the KOEO (key on engine off) state. Use the red multimeter probe to contact a bare metal section of the signal wire. The easiest way to do this is by back probing the connector.
The black probe needs to touch ground, which can be any metal part of the vehicle chassis. It should read around 5V. When back probing the live wire, the reading will be about 12V.
Fuel Level Sender and Sensor
One of the most common causes of a P0461 trouble code is a bad fuel level sending unit along with the sensor. The tricky part here isn’t necessarily testing the fuel sending unit itself. Rather, it’s accessing the assembly which often requires opening the fuel tank. Here’s where we have to issue a word of warning. Be extremely careful when operating inside an open fuel tank. The risk of fire is very real.
With that out of the way, the first thing you should do once you access the fuel level sending unit is to check for any corrosion on the sender rod or sensor itself. If there is no corrosion, you can use a multimeter to test resistance. Make sure to disconnect the unit from the harness to prevent any potential damage to the controllers.
Set your multimeter to ohms, contact the positive probe to the fuel sender, and the negative probe to ground. Move the float (ball on the end of the sender) up and down, the resistance should change in accordance with the movement.
PCM Problems
A faulty PCM or ECU can cause the P0461 code, however these instances are extremely rare. Even so, it’s something worth looking into if both the fuel level sensor and the wiring come back clean. Check your vehicle’s Technical Service Bulletin (TSB) for any recalls or any issues that can cause a false positive.
Any damage to the engine computer can cause a variety of issues, including faulty fuel readings. Most times, this would happen in an accident or flood-damaged vehicle, but excessive heat can also be an issue. Melting, burn marks, or corrosion (green/brown spots) are some signs.
Does P0461 Clear Itself?
The short answer is that once the voltages between the fuel level sensor and gauge match, the PCM will clear the code. The amount of drive cycles this takes varies, but as long as you have solved the root cause of the problem, it will clear.
Is it OK to Drive with P0461?
Not being able to tell how much fuel you have left can leave you in some tricky situations. Having a P0461 code will not affect the day-to-day running of the vehicle, so it can be left if there is no other option.
Naturally, if there is a bigger underlying issue that causes a safety hazard, you should not drive your vehicle.
Fix P0461 Code Using Quality Parts!
To most people, a P0461 code is a mild annoyance. As car people, though, our vehicles are part of the family. So, when a component fails, we want to fix it, no matter how small the issue is.
Here at eEuroparts.com, we carry a wide range of components you need for routine maintenance and extensive repairs of most European vehicles. Select your vehicle from the drop-down menu and you’ll be able to choose the parts that are a guaranteed match for your particular make and model.
