Dissection Of P2291 Code On 6.4 Powerstroke Engine: Fixing Process

There are tons of error codes present to help you repair your vehicle. The P2291 is one of the generic ones.

So, what does the code P2291 Powerstroke 6.4 mean? 

In literal terms, the code P2291 on 6.4 Powerstroke means “injector control pressure too low – engine cranking.” This means that the PCM has detected low oil pressure, which is insufficient to control the fuel injection system with the engine cranking. This code can be triggered by a low oil level, low oil pressure, or a defective injection control pressure sensor.

Now that we have a basic idea of what has happened let’s get into it.

How serious is Error Code P2291 in Powerstroke 6.4?

The error code P2291 clearly indicates a fuel pressure issue in the powertrain control module on your Powerstroke 6.4. This problem can lead to significant engine damage if left unaddressed for a long period. 

For example, low fuel pressure can cause the engine to run too lean, leading to overheating and catastrophic engine failure. 

If you see this code appear on your dashboard, continuing to drive the vehicle is not a good idea unless you must. Ignoring this P2291 DTC and continuing to drive your car can cause more expensive damage down the road. So it’s better to address the issue proactively to ensure your safety and protect your vehicle.

What Happens If You Ignore Error Code P2291 in PowerStroke 6.4?

In the worst-case scenario, your truck will not start and make horrible noises when you try to start it. 

But somehow, if you do manage to get it started, you are most likely to experience-

• Rough idling
• Loss of power
• Stalling

Suppose you still continue to ignore the code P2291. In that case, it may cause severe engine damage by overheating the engine to drive a lean air-fuel mixture. So, it would be best to get your car checked out as soon as possible when you see the P2291 code in the 6.4 Powerstroke engine.

P2291 Powerstroke 6.4: Causes, Symptoms, and Solution

Other than the ICP (injection control pressure) sensor, several causes can be behind this. Allow us to tell you what they are.

Reason	Symptoms	Solution
Low oil level	Oil pressure light on, burning smell of oil, the engine making noise, low performance, engine overheating.	Refuel.
Low fuel pressure	Oil pressure light on, burning smell of oil, the engine making noise, low performance, engine overheating.	Seal the leak in the fuel lines or replace the fuel filter.
Defective fuel pump	No fuel pressure at all, the engine won’t start	Replace the fuel pump
Defective ICP sensor	Check engine light, hard or no starting, engine stalling, poor fuel economy, reduced power and acceleration, rough idle, smoke from the exhaust	Replace the sensor

Reason One: Low Oil Level 

The fuel level is the first thing you must check when you see code P2291 in your Powerstroke 6.4 engine. This is the most common reason for triggering this error code.

Symptoms

• Oil pressure light on
• The burning smell of oil
• Engine making noise
• Low performance
• Engine overheating

Solution

Refill the fuel tank. Make sure to use the correct fuel grade. Diesel 2 is commonly used in Powerstroke 6.4 engines.

Reason Two: Low Oil Pressure 

If the oil level is okay, the code may be caused by low oil pressure. If that’s the case, a proper fuel system diagnostic is due. 

Symptoms

The symptoms of low oil levels and low oil pressure are similar. Low oil levels are one of the many causes of low oil pressure.

Diagnosis

You must perform a fuel pressure test to determine the fuel pressure level. For that, you will need a fuel pressure gauge and follow the procedure below- 

• Turn off the engine and remove the keys from the ignition.
• The test fitting is located on the front of the fuel cooler.
• Connect the fuel pressure gauge to the test fitting. Make sure that the gauge is securely attached.
• Turn on the ignition: Turn on the ignition, but do not start the engine. This will activate the fuel pump.
• Observe the fuel pressure gauge and check if the pressure is constant between three to eight PSI. If the pressure is below three PSI, there is a problem with the fuel pressure.
• Also, check for aeration of the fuel.

How To Aeration Of The Fuel in 6.4 Powerstroke

In order to aerate the fuel in a 6.4 Power Stroke engine, there are several simple steps that must be followed.

• Locate the two banjos on the fuel system – one in the front and one in the rear
• The front banjo should have a Schrader port; drill a hole in the center of the rear banjo and tap it to install a fitting
• Attach a clear hose to the fitting and run it into a gallon jug
• Turn the key on and allow the fuel to cycle through the system; repeat if necessary
• Wait until the fuel flow stops or until there are very few air bubbles in the clear hose
• Turn off the key and disconnect the tool
• Remove the banjo and reinstall it onto the fuel system
• The truck should start up quickly; repeat the process if necessary
• Keep in mind that it may be necessary to aerate the fuel system even after replacing the fuel filters

If there is low pressure in the system, then it might have been caused by one of the following:

1. A leak in the fuel lines
2. Clogged fuel filter

To check for a fuel leak in the fuel lines of a Powerstroke 6.4 engine, turn off the engine, inspect the fuel lines and connections for visible damage, and also check for loose connections. After that, turn on the engine and observe for leaks.

To check for a clogged fuel filter in a Powerstroke 6.4 engine, turn off the engine and locate the fuel filter underneath the vehicle near the fuel tank. Using a wrench or pliers, remove the fuel filter from its housing and inspect it for signs of debris, dirt, or other contaminants.

Solution

• Replace the fuel filter if it’s clogged. A new fuel filter will cost you about $70 without labor.
• If there is a small leak in the fuel lines, you can repair it with sealant.
• If there is no fuel pressure, replace the relevant wires from the battery to the low-pressure fuel pump.

Reason Three: Defective High-Pressure Fuel Pump 

There could be a defective fuel pump or no power if there is no pressure. 

The Powerstroke 6.4 has two fuel pumps: a low-pressure fuel pump and a high-pressure fuel pump. 

Symptoms

• No fuel pressure at all.
• The engine won’t start

Diagnosis

First, you must check the power of the low-pressure fuel pump. Here’s how-

• Turn off the engine and locate the low-pressure fuel pump.
• Disconnect the electrical connector that connects the low-pressure fuel pump to the wiring harness.
• Set a digital multimeter to measure voltage and connect the red probe to the positive (+) wire on the electrical connector and the black probe to the negative (-) wire.
• Have someone turn the ignition key to the “on” position (but do not start the engine).
• Check the voltage reading on the multimeter. If the low-pressure fuel pump is receiving power, you should see a voltage reading should be around 12 volts 

If the low-pressure fuel pump does not have power, it could be the PCV in the high-pressure pump. Here is how to diagnose it-

• Disconnect the battery’s negative cable to prevent accidental electrical shock or damage.
• Locate the pressure control valve, which is typically located on the high-pressure fuel pump. 
• Test the resistance of the pressure control valve’s solenoid by using a digital multimeter. The resistance reading should be between 1.2 and 2.0 ohms.
• Check the pressure control valve’s operation with a hand-held vacuum pump if the solenoid is within the acceptable range. Apply 15-20 in/Hg of vacuum to the pressure control valve’s vacuum port. If it opens and closes smoothly, the pressure control valve operates properly.
• If the pressure control valve does not operate properly, it may be clogged or faulty. 
• Remove the high-pressure fuel pump and inspect the PCV for debris or damage. 

Solution

If there is no voltage reading, check the wiring and connections between the low-pressure fuel pump and the electrical system. Look for any damaged wires or loose connections preventing power from reaching the pump.

Here is an instruction on how we did servicing the shorted wiring harness on our 2008 6.4 powerstroke –

• When dealing with a shorted wiring harness, there are several crucial steps to follow. These steps include:
• Identifying the fuse that keeps blowing out. In this particular case, the problematic fuse is fuse number 74. This fuse powers several components such as the glow plug control module, mass airflow sensor turbo actuator, EGR, throttle plate, fan clutch, and high-pressure fuel pump solenoids.
• Testing the resistance on the output side of the fuse to ground. If the resistance measures 45 ohms or less, it could indicate that there is a short in the wiring harness.
• Wiggling the wires around to check if the resistance stays the same or changes. This helps to identify if there is any loose connection or breakage in the wires.
• Disconnecting the high-pressure fuel pump connector that has a jumper harness attached to it. This connector can be easily accessed from the side.
• Testing the resistance again between the output side of the fuse to ground. The resistance should change to a higher value than 45 ohms, indicating that the short is somewhere downstream of the fuel pump connector.
• Reconnecting the fuel pump connector and testing the resistance between the two bottom pins of the connector. These pins are the power supply from the fuse that keeps blowing. There should be no resistance or an infinite value between these pins and ground. Any value other than that indicates a short in the wiring harness.
• Locating the short in the wiring harness by thoroughly inspecting it. In this case, the technician suspected that the red wire had bare copper that was shorting against the metal portion of the fuel pump. Upon inspecting the wire harness, they found the bare copper wire causing the issue.
• Repairing the shorted wire by covering it with electrical tape or by replacing the entire wire. It is crucial to test the resistance again to ensure that the issue has been resolved.
• Reconnecting the wires and checking if the fuse still blows. If the fuse does not blow anymore, it means that the issue has been resolved. If it still blows, there might be other underlying issues that need to be inspected.

But if you want to replace the harness, a new one will cost you around 15 dollars. 

If the PCV is clogged, you can clean it and see if that solves the problem. You must replace the high-pressure fuel pump if it’s faulty or damaged.

Replacing a high-pressure fuel pump would cost around a thousand dollars. A new pump costs around $700; the rest would go for labor. 

Reason Four: Defective ICP Sensor

Fuel injection systems depend on the Injection Control Pressure (ICP) sensor. The sensor measures the pressure of the high-pressure oil system that powers the injectors.

A fault in the ICP sensor can trigger the P2291 code in the 6.4 Powerstroke.

Symptoms

• Check Engine Light
• Hard or no start.
• Engine stalling
• Poor fuel economy
• Reduced power and acceleration
• Rough idle
• Smoke from the exhaust

Diagnosis

Locate the ICP sensor. The ICP sensor is behind the compressor on the inboard side of the driver’s cylinder head. 

Inspect the wiring and connector for damage, corrosion, or loose connections. 

Then measure the voltage output of the ICP sensor following the instructions in given below-

To measure the voltage output of an ICP sensor, you will need to follow these steps:

• Obtain a pigtail connector from a reliable supplier that makes good-quality original equipment parts.
• Unplug the ICP sensor and insert the pigtail connector in line with it.
• Identify the red wire on the pigtail connector, which represents voltage or power. This wire should be connected to the bottom of the ICP sensor.
• Using a multimeter, set it to DC voltage and connect the positive lead to the red wire on the pigtail connector, and the negative lead to a good ground.
• Turn on the ignition and monitor the voltage output on the multimeter.
• The voltage output of a properly functioning ICP sensor should read about a quarter of a volt, with a range between 0.16V to 0.28V.
• If the voltage output is significantly different from the expected range, then the ICP sensor may have a bad signal due to a leak or a broken wire connection.

It is important to ensure that the voltage reference is consistent and that the voltage output accurately reflects the pressure measured by the sensor. By using a pigtail connector and a multimeter, you can accurately measure the voltage output of an ICP sensor and determine if it is functioning properly.

Solution

If the ICP sensor is defective, replace the sensor with a new one. A new aftermarket ICP sensor will set you back around $22. 

Related Codes That Might Trigger With the Error Code P2291

When a Powerstroke 6.4 diesel engine shows the error code P2291, it means that there is an issue with the fuel pressure. However, this code may also cause other codes to show up, depending on what is causing the problem. Some of these related codes might include the following-

• P0087 – Fuel Rail/System Pressure – Too Low
• P0089 – Fuel Pressure Regulator 1 Performance
• P0191 – Fuel Rail Pressure Sensor Circuit Range/Performance
• P0192 – Fuel Rail Pressure Sensor Circuit Low Input

How to Prevent Error Code P2291 in Powerstroke 6.4?

Preventing error code P2291 in a Powerstroke 6.4 diesel engine involves taking proactive measures to ensure the fuel system works properly. Here are some tips to prevent this error code:

• Use high-quality fuel: Always use high-quality diesel to prevent contamination and build-up of debris in the fuel system. Do not use unrefined bio-diesel, as it has a higher chance of clogging the fuel filter and damaging the pump. 
• Regular maintenance: Keep your engine and fuel system healthy with proper maintenance. This includes replacing fuel filters and cleaning the fuel system occasionally. Experts recommend cleaning your fuel filter every 30,000 miles and the fuel system every 60,000 miles.
• Watch for warning signs: When you notice warning signs, such as a check engine light or poor engine performance, get the vehicle inspected by a mechanic right away.
• Check fuel pressure regularly: You should check the fuel pressure whenever faced with any performance issue. Staying ahead of the problem will save you time and money.
• Avoid idling for long periods: Idling wastes fuel and can cause the fuel pressure to drop. This can lead to problems with the fuel system and trigger related error codes. 

FAQs

Conclusion

P2291 Powerstroke 6.4 is a severe problem that needs to be addressed as soon as possible. However, the problem’s severity depends on the code’s cause.

If the fuel level is low, you must refuel, which may not be alarming. But suppose the issue is with the fuel pumps or the injection pressure sensor. In that case, it needs to be diagnosed and repaired immediately.

Using the right fuel is crucial to preventing this code. Along with that, proper fuel system maintenance and replacement of the necessary components are also necessary.  

Last Updated on August 30, 2024 by Rifen