Replacing The Fuel Pump In A 2006 Mercedes C230: Step-By-Step Guide

Replacing the fuel pump on a 2006 Mercedes C230 can be a complex process, and it is recommended that you get it done by a professional. However, if you are experienced in auto repair, you can attempt to do it yourself. The fuel pump is located inside the fuel tank, which can be accessed by removing the rear seat. Before starting, make sure you are working in a well-ventilated area to avoid inhaling harmful fuel vapors. Disconnect the negative battery cable, and use an anti-static siphon hose to drain the fuel tank. Depressurize the system through the Schrader valve, and then remove the access panel to the fuel pump. You will need to remove the screws holding the panel in place and gently pry it up. Once the access panel is off, you can remove the fuel pump by disconnecting the electrical connection, supply line, and return line. Install the new fuel pump by connecting the lines and electrical connection, and then reinstall the access panel and rear seat.

Disconnect the battery

Disconnecting the battery is the first step in replacing the fuel pump in a 2006 Mercedes C230. This is a critical safety precaution to reduce the chance of a fire when working with the fuel system.

• Locate the battery: The battery in a Mercedes C230 is typically located in the engine bay, near the front of the vehicle.
• Identify the negative battery cable: The negative cable is usually black and is connected to the negative terminal of the battery, which is often marked with a "-" sign.
• Disconnect the negative cable: Use a wrench or socket that fits the battery terminal. Loosen the nut or bolt securing the cable and remove it from the terminal. You may need to wiggle the cable free gently.
• Insulate the cable: Once the cable is disconnected, insulate the terminal and cable with electrical tape or a cable insulator to prevent accidental contact.
• Secure the cable: Ensure that the cable is secured and will not come into contact with the battery terminal during the fuel pump replacement.
• Work safely: Always take safety precautions when working with a vehicle's electrical system. Wear protective gear, such as gloves and eye protection, and ensure proper ventilation.

It is important to note that disconnecting the battery may cause the vehicle's computer to lose certain settings, such as radio presets or seat positions. Therefore, it is recommended to make a note of these settings before proceeding. Additionally, always refer to the vehicle's repair manual for specific instructions and safety precautions.

Remove the rear seat

To remove the rear seat of a 2006 Mercedes C230, follow these steps:

Step 1: Gain access to the fuel level sender

First, pop the plastic covers off of the seat bottom mounting nuts. Then, use a 13mm socket to remove the nuts. Pull the seat bottom away from the seat back and then out of the car.

The level sending unit mounts to the tank under the black circular cover on the driver’s side of the seat base. Use an 8mm socket to remove the six cover bolts. Remove the six bolts from the tan cover adjacent to the black cover to expose the fuel pump housing.

Step 2: Disconnect the SRS cables

Disconnect the SRS cables; one for each seat.

Step 3: Remove the rear seat

There are two hex nuts and several torx bolts. First, remove the 40% seat (rear passenger side) from the car. The 60% seat is very heavy, so just slide it to the location of the 40% seat so that you can work on the driver side.

Step 4: Access the fuel pump

Fold the floor mat (driver side corner) and you will see a round cap covering the access hole. The cap is attached to the body by sealant only. Remove the seal and lift the cap. You will see the top of the fuel pump.

Step 5: Remove the rear seat

There are four 13mm nuts holding the bottom cushion to the body. Remove the nuts and lift the cushion up and out of the vehicle.

Remove the access panel

To remove the access panel, start by disconnecting the negative battery cable. Next, remove the rear seat cushion. You can refer to the article on removing seats from the same source. Once the rear seat is removed, you will see the access panel to the fuel pump on the right-hand side. Remove the six 8mm screws holding the panel in place and gently pry it up. Be careful not to damage the small sticky gasket between the panel and the body of the car, as it helps to reduce noise and vibration.

Disconnect the electrical connection

To disconnect the electrical connection, you will need to relieve the fuel pressure. To do this, first, disconnect the electrical plug from the top of the fuel pump unit. Then, start the car and let it run until it shuts off.

After that, head back to the sending units and unplug all the connections to the level sending unit. Next, remove the clamp from the locking ring using a 7mm socket and a flathead screwdriver. Spread the locking ring and pull it off the fuel pump assembly.

Now, pull the fuel pump assembly out of the tank. As you do this, the assembly will want to separate into two pieces. Disconnect the electrical connection from the top piece and then remove it from the tank.

Finally, disconnect the three hoses and the one remaining harness plug from the assembly.

Remove the fuel pump

To remove the fuel pump from your 2006 Mercedes C230, follow these steps:

First, disconnect the negative battery cable. Remove the fuel cap, then slide an anti-static siphon hose down the fuel filler neck to pump out the fuel from the tank into an approved storage container.

Next, depressurise the system through the Schrader valve under the hood of the car. You can then remove the rear seat to access the fuel pump. With the seat removed, you will see the access panel to the fuel pump on the right-hand side. Remove the six 8mm screws holding the panel in place and gently pry it up.

With the access panel removed, you can now see the locating cover and ring seal on the pump. There is a small arrow on the locating cover that will line up with a mark on the tank when you reinstall the pump. Use a large claw-type wrench to remove the ring seal.

Remove the ring cover along with the shaped seal. Note how the two female ends in the cover mate with the two male ends on the pump. Now, grasp the pump and remove it from the tank, being careful not to damage the fuel level unit attached to it.

With the pump out of the fuel tank, release the electrical connection, supply line, and return line by squeezing the appropriate release tabs.

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