How To Bypass A Car Fuel Pump Relay – Guide

How To Bypass A Car Fuel Pump Relay – Guide

The fuel pump relay performs a critical function in your car. It is responsible for supplying the voltage needed to pump the fuel to the engine.

As such, if it goes bad, your car may stall. The good news is that you can bypass it, thus enabling the car to function as usual.

However, you should know that bypassing the fuel pump relay can cause an adverse safety issue.

How to bypass a car fuel pump relay

Therefore, you should only bypass a car fuel pump relay when you are in an emergency. Depending on the car’s model, there are two ways you can do so.

You can either use a single jumper wire or a three-jumper wire as described below.

Steps To Follow When Bypassing A Car Fuel Pump Relay

1. Gather The Necessary Tools

It would be best to gather all the tools you need in advance. It will save you time and make the process efficient and less tedious.

These tools include a single jumper wire, a three-jumper wire, a screwdriver, a solder, a soldering machine, a pair of scissors, a nut driver, a lighter, two screwdrivers, a soldering gun, and electrical insulation tape.

2. Drive The Car To An Empty Parking Space

When it comes to bypassing the fuel pump relay, safety should be your number one priority. So, drive the car to an empty parking space and engage the parking gears.

3. Switch Off The Car

Since you will be dealing with electrical components, you must turn off the car. It will prevent you from getting electric shocks and causing harm to the car’s components.

4. Remove The Battery

You also need to disengage the battery from the car since you will be dealing with a fuel pump relay that draws voltage from it.

But when doing so, ensure that you disconnect the negative cable first.

Also, make sure that you remove the battery from its compartment to give you space to work on the integrated power module (IPM).

5. Bypass The Fuel Pump Relay

As pointed out earlier, there are two ways of bypassing the fuel pump relay. At this stage, you can choose which method to use.

Bear in mind that your choice will purely depend on the model of your car. If your car has a relay plugged into the IPM, you can use a single jumper wire to bypass it.

However, if your car’s fuel pump relay is located inside the IPM’s circuit board, you will have to use a three-jumper wire. Let’s look at how you can use each method below.

Bypassing The Fuel Pump Relay Using A Single Jumper Wire

It is the easiest method that you can use to bypass a car fuel pump relay. You only have to identify the relay and unplug it from its socket.

Once you have done so, replace it by inserting one end of the single jumper wire to one of its sockets and the other end of the jumper wire to the other socket.

You can then return the battery and start the car. If the single jumper wire is placed correctly, the car should start and run properly.

Bypassing The Fuel Pump Relay Using A Three Jumper Wire

It is the most complex method that you can use to bypass the fuel pump relay. It is often argued that you should only use it when you are sure of what you are doing.

It is because any tiny mistake can cause severe damage to your vehicle. Fortunately, by using the following steps, you will be in a better position to do so without any glitches.

1. Unhook The IPM Power Cable And The Relay Cable

The IPM cable supplies power to the IPM, which gives power to the relay cable. To remove them, use a nut driver to disengage the nuts that hold them to the IPM.

It is important to note that if you don’t remove them, you will have a hard time navigating through the IPM.

Bypassing a car fuel pump relay

2. Open The Interior Of IPM

Since the fuel pump relay is located inside the circuit board, you must open the IPM. You can remove the nuts that hold it in place and pull it up.

But you should be careful when doing so since if you apply a lot of force, you might break the connections in the circuit board.

Sometimes, you might have to use two screwdrivers to help you pull it up. To do this, insert one screw in one of the IPM’s corner holes and the other screw in the other hole and lift the IPM.

3. Pull Out The 40 And The 50 Pin Connectors

Now that you have access to the IPM’s circuit board, you can go ahead and identify the 40 and 50 pin connectors.

The 40 pin connector is found at the bottom of the circuit. On the other hand, the 50 pin connector is located at the top of the circuit board.

Once you have found time, unplug them from their sockets.

4. Work On The Brown Cable On The 40 Pin Connector

This bypass step involves identifying the brown wire on the 40 pin connector and disengaging it from the connector at its tip. You can use a pair of scissors to do so.

You can then peel its head using a lighter and join it to the brown wire of the three-jumper wire. But it would be best not to forget to solder the connection to make it firm.

Also, it is essential to tape this part to prevent any short circuits.

5. Identify The Blue And Pink Cables On The 50 Pin Connector And Work On Them

Here, you will repeat what you did in step four above.

But in this case, you will be joining the blue and the pink cables in the 50 pin connector to the blue and pink cables in the three-jumper wire, respectively.

However, unlike when working on the blue and brown cables, the case of the pink cable is somehow different.

It is because you won’t be disengaging it from the 50 pin connector but peeling a small section of it using a razor blade.

You will then connect the pink cable from the three-jumper wire into the peeled area.

6. Return The Connections

It is another step that should be covered carefully. It involves returning the 40 and 50 pin connectors to their sockets.

It also entails returning the IPM power cable and the relay cable to their position.

7. Secure The Relay

To ensure the safety of the relay, use a screw to hold it onto the car’s wall.

8. Make The Three Jumper Wire Firm

Using a knot, tie the three jumper wire to one of the circuit cables to prevent the connections from disengaging when the car vibrates.

9. Put The Battery Back

Now, put the battery back in its place and connect its cables back. Remember to start with the negative cable to avoid causing any plugs.

10. Check If The Bypass Works

You are almost done! You only have to check if the bypass works.

The only way to know is by starting the car. If the vehicle starts and runs well, then the process is successful.

11. Close The IPM

Since you have established that the car fuel pump relay bypass was successful, you can close the IPM. It is vital to do so carefully to avoid interrupting the connections.