P1405 Ford- Meaning, Causes, Symptoms, & Fixes

It is important to ensure your Ford is in good condition to avoid performance issues and environmental pollution. One way of checking if your car has a problem is by running an OBD II system. The OBD II system will show a specific code if there is an issue. Depending on the meaning of the code, you can fix the issue or wait until you have the money and time to do so. Therefore, you should always be aware of the different codes that can appear in your Ford vehicle. One of these codes is P1405, which is an emission-specific code. We will explain all you need to know about this code below.

Meaning of code P1405

Modern vehicles are fitted with Exhaust Gas Recirculation (EGR) system, which enables exhaust gas to move back to the combustion chamber, where it is burned. This process reduces pollution to the environment.

The EGR has a tube on its high and low- pressure sides. The two tubes are attached to the Differential Pressure Feedback Electronic (DPFE) Sensor. The Power Control Module indirectly controls the EGR through the DPFE sensor. When the PCM establishes that pressure on one side of the EGR system has gone out of range, it instructs the EGR to open. It also tells the EGR the amount of exhaust gas it needs to let out to return the pressure to an optimal level. If the EGR pressure level goes outside the specified range and the PCM cannot rectify it, the PCM will indicate code P1405. Usually, this code is defined as “DPF EGR Sensor Circuit High Voltage Detected.”

Symptoms of code P1405

Since an issue with the EGR affects the engine’s performance, this code is associated with many symptoms described below.

1.      Check engine light will come on

Anything affecting the engine’s operation will cause the check engine light to come on. That being the case, you shouldn’t fully count on this symptom to tell you if the EGR has issues.

2.      Engine misfires

If the EGR malfunctions, more exhaust fumes will flow into the engine. This will affect the air-mixture ratio in the combustion chamber resulting in engine misfires.

3.      Poor fuel economy

As indicated, an insufficient EGR may allow more exhaust fumes into the combustion chamber. This will necessitate the usage of more fuel to burn it. 

4.      Your Ford will fail the emissions test

It is a requirement for every vehicle to pass the emission test. However, a faulty EGR will release more carbons into the atmosphere. This will make your Ford fail the test, resulting in huge fines and even failure to get a registration certificate. 

5.      Poor engine performance

You will always notice engine performance issues when there is code P1405. A faulty EGR will affect the combustion process resulting in less power to the engine. As such, you may notice symptoms such as poor acceleration, rough idle, and engine stalling. 

What causes code P1405?

Remember that when the PCM indicates high voltage has been detected, it does not mean electric voltage but that the EGR pressure has gone out of the normal range. You will notice code P1405 when one of the following issues is present.

1.      Too much soot in Diesel Particulate Filter (DPF)

The function of the DPF is to filter out solid particles in the exhaust fumes. This prevents the particles from entering the EGR tubes and affecting the pressure level. Usually, when the soot exceeds a certain level, the PCM initiate a process to burn them. However, if the soot can’t be fully burned, the PCM will indicate code P1405.

2.      Clogged EGR tubes

As time passes, small amounts of solid particles will enter the EGR tubes. This will eventually clog the tubes. If they are blocked, exhaust fumes will flow in the opposite direction resulting in high-voltage scenarios being relayed to the PCM. 

3.      Faulty DPFE sensor

If the DPFE sensor goes bad, wrong information will be relayed to the PCM. As a result, the exhaust gas pressure between the high and low sides of the EGR will not be balanced. Moisture and heat in the exhaust gases can damage the DPFE sensor. Also, the box that houses the DPFE sensor may get corroded, reducing the sensor’s sensitivity to pressure imbalance. 

4.      Bad EGR valve

The PCM normally causes the EGR valves to either open or close, depending on the pressure level. If this valve malfunctions, a high-voltage situation will be created in the EGR. The EGR valves can remain open or closed due to soot or dirt from fuel. Your Ford’s EGR valves will typically go bad if you are used to driving for short distances.

5.      Clogged intake manifold

The intake manifold allows exhaust fumes to enter the engine. Like the EGR tubes, they can get clogged due to the build-up of soot. When this happens, the pressure in the tube will exceed the required level, and code P1405 will be produced.

6.      Defective vacuum regulator

The PCM controls EGR valves through the vacuum regulator. This regulator has a solenoid that relies on electric voltage to work. If the solenoid develops electric shorts, the vacuum regulator will not work. This will make the EGR valves stuck open or closed; hence making the PCM to indicate a high voltage situation. 

7.      Malfunctioned PCM

The PCM can develop bugs indicating there is code P1405, yet it is not valid. This can happen when you install external devices into the vehicle. The good news is that this is always a temporary issue that doesn’t cause any harm to your Ford vehicle.

Can you drive with code P1405?

 Even though it’s possible to drive with code P1405 present, it is highly recommended that you fix it before using the car. This is because it will cause engine performance issues, resulting in poor fuel economy. It will also result in more EGR emissions; hence making your Ford vehicle fail the EGR test. Thankfully, you can apply the fixes below to eradicate code P1405.

1.      Clean the DPF 

Before cleaning the DPF, it is essential to note that this is a delicate component that needs extreme caution. As such, if you think you don’t have the skills to do it, take your Ford to a specialist to avoid damaging the DPF. However, if you are confident that you can clean the DPF without any issue, take it out and examine if there are carbon build-ups. If you can’t see its white surface, the DPF is clogged. Fortunately, there are several ways of cleaning the DPF. You can clean it using compressed air and water or use chemicals such as spray-on systems and fuel additives. Whichever way you clean the DPF, the carbon build-ups will be removed entirely. 

2.      Clean the EGR tubes

One way of knowing if the EGR tubes are clogged is by checking the exhaust pipe. If you notice that a black liquid is coming out of the pipe, the EGR tubes are likely clogged. You can then start cleaning them using a carburetor cleaner and a toothbrush. 

3.      Replace the DPFE sensor

You can test if the DPFE sensor is faulty by using a multimeter. To do so, look for the specific voltage of the DPFE sensor in your Ford manual. After that, set the multimeter to 20V and connect it to the sensor. If the multimeter reading differs from the specific value, you have a faulty DPFE sensor. You should replace a lousy DPFE sensor instead of repairing it to achieve a permanent solution.

4.      Check and clean the EGR valve

Unbolt the valve from the EGR and examine it. If carbons prevent them from opening or closing, use a screwdriver to remove them. However, if you deduce that the EGR valve is broken, you will have to replace it.

5.      Clean the intake manifold

Unfortunately, there is no clear way of telling if the intake manifold is blocked. You only have to rely on the above symptoms. If your Ford shows most of the above symptoms, its intake manifold is likely clogged. Luckily, cleaning it is pretty easy. You only have to spray a power-forming cleaner on the manifold. This fluid will clean the intake manifold in a matter of minutes. However, the cleaning fluid may not be efficient if the carbons have accumulated for a long time. In this case, you will have to replace the intake manifold.

6.      Replace the vacuum regulator

The regulator is bad if you connect a multimeter to the vacuum regulator, and no reading is displayed. The bad news is that a faulty vacuum regulator cannot be repaired; hence you have to install a new one to remove code P1405. Remember to disconnect the EGR tubes when running the test.

7.      Reboot the PCM

If you couldn’t find anything causing code P1405, rebooting the PCM should fix the problem. Your Ford manual should give you the procedure on how to do it.

To sum up,

Code P1405 is an emission-specific code. It indicates that the EGR pressure has gone out of range. It is mainly caused by soot that clogs most of EGR’s components. These components include DPF, EGR tubes, and an intake manifold. It can also be seen when the DPFE sensor, the vacuum regulator, and the PCM malfunction. When this code is present, you will likely notice symptoms such illuminated check engine light, more EGR emissions, poor engine performance, etc. Fortunately, it is easy to clean and replace the affected parts. 

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