Replacing The Fuel Level Sensor In Your Buick Lacrosse

The fuel level sending unit in a Buick Lacrosse is located in the fuel tank and sends a signal to indicate the amount of fuel remaining. When the fuel level sending unit fails, the fuel gauge will not operate, and the check engine light may come on. To replace the fuel level sending unit, a technician will need to remove it from the fuel tank, which may involve removing the fuel tank itself. This repair can cost between $1,140 and $1,320.

Some Buick Lacrosse owners have reported issues with the fuel pressure sensor, which can cause reduced engine power when accelerating or climbing a hill. This may be due to a faulty fuel pressure regulator or a problem with the high-pressure fuel pump. In some cases, the issue could be related to the throttle position sensor.

Average costs for replacement

The average cost to replace a fuel level sensor in a Buick Lacrosse varies depending on the type of sensor.

The average cost to replace a fuel level sending unit is between $1,140 and $1,320. Labor costs are estimated between $230 and $290, while parts are priced between $910 and $1,031.

The average cost to replace a fuel tank pressure sensor is between $295 and $348. Labor costs are estimated between $201 and $253, while parts are typically priced around $95.

The average cost to replace a fuel pressure sensor is around $100, with $5 for parts and $95 for labor. However, prices vary depending on the year of the Buick Lacrosse. For example, the shop/dealer price for a 2010 Buick Lacrosse V6-3.0L is $976.71 - $1358.13, whereas the price for a 2005 Buick Lacrosse V6-3.8L is $546.69 - $807.21.

The average cost to replace a low oil level sensor is $122, with $27 for parts and $95 for labor. Again, prices vary depending on the year of the car. For instance, the shop/dealer price for a 2014 Buick Lacrosse V6-3.6L is $242.72 - $329.90, whereas the price for a 2008 Buick Lacrosse V6-3.8L is $172.84 - $221.04.

Symptoms of a faulty fuel level sensor

A faulty fuel level sensor in a Buick Lacrosse can cause a few issues, which are symptoms of a failing or faulty sensor. One of the most common symptoms is a fuel gauge that fails to operate, leaving the driver unsure of how much fuel is in the tank. In some cases, the check engine light may also illuminate on the dashboard, indicating an issue with the engine.

In the case of a faulty fuel level sensor, the on-board diagnostic (OBD) trouble codes stored will be related to the fuel level sensor if the check engine light comes on. This can help identify the issue as being sensor-related.

Another symptom, as reported by a Buick Lacrosse owner, is a fuel gauge that gets stuck on the full mark after filling up the tank. This issue can be caused by sulfur in the gas, which corrodes and breaks the small wires in the sensor. This issue may require repeated replacement of the sensor, as it is a symptom of a wider problem.

It is important to note that fuel level sending units rarely fail and are often not the root cause of issues. However, when they do fail, the above-mentioned symptoms are likely to occur.

How the fuel level sensor works

The fuel level sensor is located in the fuel tank and sends a constant signal indicating the amount of fuel that remains in the tank. In most systems, the fuel level sensor will have a mechanical arm extending to the top of the fuel inside the tank. It will float on the top of the fuel, and as the arm moves down, the signal strength from the sending unit decreases. That information is sent to the fuel level gauge for driver awareness. When the arm gets low enough, the light on the dashboard will be turned on, alerting the driver to stop for fuel.

The 3 main sensing technologies are ultrasonic, float and reed switch, and capacitive. Float and reed switch is the most commonly used type of fuel level sensor. It is essentially a float with a magnet in it that rides up and down a vertical shaft with the fuel level. As the magnet in the float passes reed switches at various levels on the vertical shaft, they become triggered.

Software is used to filter the rapidly changing signal (due to sloshing). It is able to smooth out the output and give you a good idea of the real level. Ultrasonic sensors, on the other hand, are based on the Time of Flight principle. They generate a sound wave that bounces off the surface of the fuel and returns to the sensor face. As the Speed of Sound (SoS) is a fixed value, the sensor can tell how far away the fuel is (and therefore how much there is) based on how long the sound wave took to return.

How to diagnose issues

To diagnose a faulty fuel level sensor in a Buick Lacrosse, there are a few symptoms to look out for. The most common issue is a faulty fuel gauge. This may present as the gauge getting stuck on full after filling up the tank, or the gauge failing to operate altogether. In some cases, the check engine light may also illuminate, and an on-board diagnostic (OBD) trouble code will be stored in the vehicle's computer.

If you suspect a problem with your fuel level sensor, the first step is to take your car to a qualified technician. They will test the system and verify that the gauge is working properly under the correct conditions. They will also check the fuses and compare the voltage from the fuel sending unit to the manufacturer's specifications. If the gauge and fuses are in working order, and the voltage readings are abnormal, this indicates that the sensor has failed.

It's important to note that a faulty fuel level sensor is not a common issue in the Buick Lacrosse, and other problems may be causing the symptoms outlined above. For example, a faulty crank position sensor, cam position sensor, air flow sensor, boost pressure sensor, or temperature sensor can all mimic the symptoms of a bad fuel rail sensor. Therefore, it's essential to have a qualified technician diagnose the issue to determine the exact cause of the problem.

How to replace the fuel level sensor

Firstly, it is important to understand the function of the fuel level sensor. The sensor is located in the fuel tank and sends a constant signal indicating the amount of fuel remaining. In most systems, the fuel level sensor has a mechanical arm extending to the top of the fuel inside the tank. This arm floats on the fuel and moves down as fuel levels decrease, causing the signal strength from the sending unit to decrease. This information is sent to the fuel level gauge on the dashboard, alerting the driver when fuel levels are low.

Now, onto the replacement process:

• Identify the location of the fuel level sensor. In some vehicles, there is a service access panel underneath the trunk linking or back seat, providing access to the fuel tank. In other cases, the fuel tank must be removed to access the sensor.
• Disconnect the battery prior to beginning any work on the fuel system.
• Remove the fuel level sensor from the fuel tank. This may involve unbolting it and disconnecting it from fuel and electrical connectors.
• Compare the movement of the old sensor with the new one to ensure proper calibration. Adjust the arm if necessary to match the specifications of the old sensor.
• Install the new fuel level sensor in the same location, ensuring all connections are secure.
• Reconnect the battery and turn on the vehicle.
• Test the new sensor by checking the fuel gauge on the dashboard to ensure it is functioning correctly and providing accurate fuel level readings.

It is important to note that working with fuel systems can be dangerous, and proper precautions should be taken to avoid fire hazards. Additionally, if you are uncomfortable with any aspects of the replacement process, it is best to consult a professional technician or mechanic.

The cost of replacing the fuel level sensor in a Buick LaCrosse can vary depending on the specific model year and labor costs in your location. On average, the parts for this repair can range from $95 to over $1000, while labor costs can add several hundred dollars to the total expense.

Frequently asked questions