How to Fix the P0087 Code In 6.7 Cummins?
The error code P0087 is very common in a 6.7 Cummins engine. But that doesn’t mean it won’t cause you problems.
So, to diagnose and solve this, we must know what the P0087 code 6.7 Cummins engine means.
The P0087 code says, “Fuel rail or system pressure is too low.” This indicates a problem with the fuel system of your engine. To be more specific, the issue lies within the fuel filter, fuel pump driver module, or fuel pressure sensor. Other than the error code and the check engine light, you’ll experience engine misfire, low fuel economy, and other symptoms.
Now that we know what and where the problem is, let’s attempt to solve it.
What Are the Causes of the P0087 Code in a 6.7 Cummins?
Causes | Symptoms | Solution |
| Clogged Fuel Filter | The check engine light is illuminated; the engine misfires; lack of power; and poor fuel economy. | Clean or replace the fuel filter |
| Clogged Fuel Supply | Replace the fuel line | |
| Faulty Fuel Pump Driver Module | Replace the fuel pump driver module | |
| Faulty Fuel Pressure Sensor | Replace the fuel pressure sensor | |
| Faulty ECM | Replace the ECM |
The P0087 code warns you about low fuel pressure on your engine. This means somehow the fuel supply is restricted, which indicates issues with the fuel filter, fuel pump driver module, and fuel pressure sensor.
This problem will cause your engine to misfire, lose power, and have poor fuel economy. Now let’s have a session on the solutions to the problems you are facing due to this error code.
How to Fix the P0087 Code In 6.7 Cummins?
To fix or reset the error code, all you need to do is fix the issue your engine is having. Although this sounds pretty easy, in reality, you will have to diagnose some of the components of your fuel system, starting with the fuel filter.
Reason One: Clogged Fuel Filter
The code P0087 indicates a low fuel pressure in your vehicle. That means not enough fuel reaching the fuel rail. That means a component in the fuel system has been damaged or clogged somehow.
The first component you need to look at is the fuel filter.
Diagnosis
Before you run any diagnostics on your fuel filter, you will have to drain out all your fuel. To do that, pop up your hood and locate your brake booster. Then, on the left side, there is a black plastic box, which is the fuel filter.
Besides the fuel filter, a little more below, there should be a small yellow switch, which will let you drain the fuel. So, place a tray under your vehicle.
Now that your fuel has been drained, you will need to take the fuel filter out. You already know where that is, so get your ratchet and socket to match the bolt of the plastic cover.
Use the ratchet and socket to open up the plastic cover and take out the fuel filter. The filter should still be dripping with fuel. So don’t forget to hold it for a couple of seconds before taking it out.
Now, you will need to check if it is damaged or clogged.
Solution
Fuel filters can be cleaned easily with fuel system cleaners (our pick: Chevron Techron Concentrate Plus Fuel System Cleaner). Use a nozzle to spray the filter down, then tap the filter to take out any dirt. Then you will need to let it sit and dry for about an hour.
When you’re finished cleaning it, put it back in your vehicle. Or, you can just get a new one.
Reason Two: Clogged Fuel Supply Line
If the fuel filter is fine, you need to move on to the fuel supply line. A clogged fuel supply line could also be the reason behind the low fuel pressure in the engine.
Diagnosis
To check if the fuel supply line is clogged or somehow restricted, you need to perform a fuel pressure test. Your 6.7 Cummins engine should have a fuel pressure port in the fuel rail. All you need to do is use a pressure tester on it to measure the pressure.
The recommended fuel pressure is about 12 to 14 psi. If it’s lower than that, then there is a problem with the fuel supply lines. To ensure that the issue is with the fuel supply line, you will need to visually check all the fuel lines.
It should be obvious if there is a leak or if the fuel supply line is bent out of shape.
Solution
If you find your fuel lines leaking or damaged, they will have to be replaced. Replacing the fuel lines is a difficult task for anyone who does not have the special skills required. So, you better get it done by an expert.
Or if you insist on doing it yourself, here is a guide:
Reason Three: Faulty Fuel Pump Driver Module
The fuel pump driver module, or fuel control actuator, controls the fuel pressure, taking commands from the ECM. So, the driver module might be the root cause if your vehicle has low fuel pressure.
Diagnosis
The fuel control actuator is attached to the CP3 fuel pump by three bolts. Locate it and undo the screws to take off the actuator. Once you have done it, the diagnosis is pretty simple. Just shake the actuator to see if it rattles.
If it does, then the actuator is fine; otherwise, there might be something wrong with it.
Solution
If the fuel control actuator is defective, you’ll have to replace it with a new one. Test the new one before installing it.
Reason Four: Faulty Fuel Pressure Sensor
The fuel pressure sensor detects the fuel pressure on your vehicle and then sends data to the ECM. The ECM then sends commands to the actuator, which executes them. That means if the sensor is faulty and sends the wrong information to the ECM, it can trigger the P0087 code.
So, you will have to check if the sensor is really the problem. The fuel pressure sensor is located right on top of the fuel rail.
Diagnosis
To test the pressure sensor follow the steps below,
- Disconnect the pressure sensor.
- Have someone turn the ignition on.
- You can see there are three lines in the sensor plug. One is for the sensor reference voltage, one is for the ground, and another for the signal line.
- Then use your multimeter to test the reference voltage line. Touch the sensor reference line with the multimeter’s red probe and the black probe to the ground. There should be 5 volts present.
- Next, do the same but with the battery-positive terminal and the sensor ground line. The voltage should be 12.6 volts.
- After that, reconnect the pressure sensor and touch the red probe at the signal line. With the ignition key turned on, the voltage reading should be half volts.
- If that does not happen, use a test light connected to battery power and touch the signal line with it. Then, measure the volt of the signal wire using the multimeter again. The signal wire should give out 12.6 volts momentarily.
You should also check the pressure sensor visually. Loosen the bolts to take the sensor out and look for any damage or corrosion.
Solution
If the test fails, then that means the sensor is faulty. So, you’re going to have to replace it. You’ll need to do the same if it’s visually damaged. Here is a video that will show you the complete process of replacing the fuel pressure sensor-
If it’s dirty or corroded, you can try to clean it up with a corrosion cleaner, reinstall it, and see how it goes. Here is how you can clean it-
- Disconnect the negative battery cable to prevent any electrical accidents while working on the fuel system.
- Locate the fuel pressure sensor’s electrical connector and disconnect it.
- Using a fuel pressure sensor cleaning kit or a carburetor cleaner, carefully spray the sensor and the area around it to remove any dirt or debris. In order to protect yourself from the chemicals used in the cleaning process, it is advisable to wear gloves and goggles.
- Once the sensor is clean, reattach the electrical connector and start the engine to check if the sensor is functioning properly.
Reason Five: Faulty ECM
If all the fuel system components check out fine, then the ECM could be the culprit. That is rarely the case, by the way.
An ECM commands all the modules and also detects all the errors within your vehicle. So, it’s possible to get this code along with a bunch of others if you have a bad ECU.
Testing an ECM could be pretty complicated, so we suggest going to see an expert if you suspect it is not working. Getting an expert to diagnose your ECU may cost you a couple of hundred bucks.
Solution
A defective ECM is not serviceable. So, you will have to replace it if you find it defective. ECMs can be super expensive, so do not go replacing them on a whim.
An OEM ECU can cost you thousands of dollars, whereas aftermarket ones cost between $500 and $800.
Can You Drive If You Have Error Code P0087?
Yes, it is possible to drive around with error code P0087, but it would be frustrating. Your engine will misfire, resulting in poor fuel economy. If the fuel system is leaking, you will continuously leak fuel.
On top of these, your vehicle will lose power, so your engine will have trouble accelerating. To sum it up, your vehicle will not be the same without fixing the error code.
So, it is recommended to solve this issue as soon as possible. If you must drive the truck, drive it to the mechanic’s garage.
Read More-
FAQs
What ruins a fuel pump?
Overheating, contamination, and wear are the major causes of fuel pump failure. Debris and dirt can sometimes make their way into a fuel tank, where they can pass through the filter and enter the pump. As a result, these contaminants block the flow and put an unnecessary burden on the fuel pump.
Does running low on gas damage the fuel pump?
Yes, it is possible to damage your fuel pump by running low on gas. Since gasoline acts as a coolant for the electric fuel-pump motor, when you run low on gasoline, the pump is able to suck in air, which creates heat and can cause the pump to fail prematurely.
Is there a recommended oil weight for Cummins 6.7?
There is a specific recommendation from Cummins for Valvoline oils to be used in their engines. For temperatures above 0 degrees Fahrenheit, use 15W-40 oil, and for temperatures below 0 degrees Fahrenheit, use 5W-40 oil.
Conclusion
The P0087 code in a 6.7 Cummins engine denotes low fuel pressure in your engine. This is a common issue but a frustrating one, as the user will have to diagnose the whole fuel system to find out the problem.
The issues mainly reside in the fuel filter, fuel pump, fuel pressure sensor, and fuel control actuator. However, in rare cases, a damaged ECM could cause the issue.
Once the code has been triggered, it is better to reset it as soon as possible. Otherwise, your engine’s performance will decrease until you fix it.
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