Ford’s Heavy Duty trucks are built to last, which means that they only feature durable, quality-made, big engines that can withstand all the abuse that comes with daily towing and hauling.
The Ford 6.7L diesel V8 Powerstroke is precisely one of those engines, but as with every engine out there, fault codes will inevitably occur.
In this article, we will go over the Ford P2291 fault code and tell you all you need to know about it.
The P2291 code refers to an error with the engine cranking, more specifically, the injector control pressure is too low. Initially, this code isn’t the end of the world, meaning you can drive your car on shorter distances, but over time, it will worsen.
Fixing this problem shouldn’t be too big of an issue if you possess decent experience working with cars. The overall costs to fix this problem vary depending on what needs fixing.
Either way, if you want to know more about this code, what it means, how to solve it, and how much it is going to cost you, be sure to read this article to find out!
What does the P2291 code mean?
The P2291 code means that the PCM (Powertrain Control Module) has detected that the injector oil pressure is below the adequate factory-set threshold while cranking the engine and while the engine is idling.
This problem is typically caused by a damaged ICP sensor, damaged wiring, low oil levels, oil dummy plug problems, turbo wastegate issues, and a faulty PCM.
Symptoms of the P2291 Code
Before the P2291 code appears, you’ll typically start noticing some symptoms.
These include your engine being harder to start or rough idling, low cranking before starting, the engine refusing to start completely, excessive smoking, and strange noises.
Hard to Start and Rough Idling
If your Ford 6.7 Powerstroke feels incredibly lazy to kick into life or/and if it idles incredibly roughly, chances are that something is wrong with the ICP system.
Many owners of various diesel engines point out that this is one of the more common symptoms of a problematic ICP and the associated P2291 code.
Long Cranking Before Starting
Sometimes the engine itself runs rather smoothly, but it takes a while before it kicks in. If the engine cranks for a suspiciously long time before starting, it is likely due to an ICP-related problem.
If you get the P2291 code and long cranks, the problem is most definitely the ICP system.
Refuses to Start Completely
If this problem persists, it could eventually lead to you not being able to start the car up completely as is often the case with the P2291 code.
In general, this is one of the most common symptoms of the P2291 code in general, especially for those who tend to ignore the Check Engine Light tirelessly.
Excessive Smoking
Another relatively big symptom of a P2291 code going unnoticed is if the truck starts emitting large quantities of either black or white smoke. However, there are numerous issues out there that can lead to excessive smoking.
On the other hand, if you notice large quantities of gray/blue smoke, it is due to your car burning too much oil.
Strange Noises
Lastly, we also need to mention peculiar whistling noises coming from the front engine compartment while the car is running. These noises tend to become louder and more aggressive when pushing the accelerator.
Engine sputtering can also be linked to the P2291 code and it leads to the engine not being able to achieve full and consistent combustion capacity.
Causes of the Error Code P2291
The P2291 fault code is most commonly caused by a damaged ICP sensor, damaged wiring, low oil levels, dummy plug problems, turbocharger wastegate problems, and issues with the Powertrain Control Module (PCM).
Damaged ICP Sensor
The ICP sensor is an expendable component, which means that it can fail during the car’s lifespan. If that indeed happens, it is going to cause the pump to exert way too much pressure on the oil, which eventually is going to destroy the oil pump itself.
This can also lead to oil sludge sediments, dirt, and debris depositing near/in the oil pump and also cause it to die.
Either way, if these problems aren’t dealt with immediately, they are going to cause the car to experience problems during start-up or while idling
Damaged Wiring
Sometimes, the ICP and the rest of the system run trouble-free, but the check engine light and the dreaded P2291 fault code both turn on. If this is the case, the wires leading to the system can get cut, burned, or damaged.
Believe it or not, this is a common occurrence as these tires are located near hot engine components and tend to get burned if they come in contact with anything hot.
On the other hand, if they fluctuate between cold and warm temperatures over time, it is going to make them brittle.
Low Oil Levels
The first thing to pay attention to when it comes to oil pressure-related problems is to check the engine oil levels. Sometimes, a leak can occur and inevitably affect the entire pressure of the system, which often leads to the P2291 code.
As not many people are vigilant when it comes to proper oil replacement schedules, these problems happen much more often than one would imagine.
Also, if the oil itself is dirty, it can also prompt the system to think that the oil levels are low simply due to not being able to maintain constant pressure.
Dummy Plug Problems
The 6.7 Powerstroke is equipped with specific dummy plugs in order to prevent oil from flowing out of the oil rails while circulating the system. If a dummy plug gets damaged, the o rings are going to break apart and lead to an oil leak.
Problems with dummy plugs are first going to affect the cranking duration of the engine and eventually will lead to the engine not being able to start up at all.
Many Ford owners recommend replacing the dummy plugs and the standpipes together in order to stop this issue from ever taking place.
Turbocharger Wastegate Solenoid Problems
Before going any further, we do need to mention that turbocharger solenoid wastegate problems aren’t commonly associated with the P2291 code, but there are some rare instances in which they are.
This solenoid is tasked with controlling the boost coming from the turbocharger, which means that any problems with the system are going to lead to subpar performance.
However, the most obvious problem with the turbocharger wastegate is the whistling sound coming from the engine bay area.
Powertrain Control Module (PCM) Problems
Last, but certainly not least, the PCM is a crucial component to the entire ordeal as it is the one detecting the lack of oil pressure, which prompts up the P2291 code.
Sometimes the code can come up due to problems with the powertrain control module and the best idea to approach it is to test the PCM by trying to clear the code.
Also, the module itself can be okay and the issue can also be due to damaged or corroded wiring that leads to the Powertrain Control Module.
| Causes Behind the P2291 Error Code on the 6.7 Powerstroke Engine | Common Symptoms |
| A Damaged ICP Sensor | Starting problems and engine sputtering. |
| Damaged Wiring | Long cranking and not wanting to start |
| Low Oil Levels | Rough idle, not wanting to start, engine sputtering. |
| Dummy Plug Problems | Long cranking, not wanting to start, excessive smoking. |
| Turbocharger Wastegate Problems | Whistling noises, excessive smoking, subpar performance |
| Powertrain Control Module Problems | Just the code and the check engine light |
How serious is the P2291 code?
At, first, a P2291 error does not tend to be overly dangerous for your car if the problem isn’t due to low oil levels or serious problems with the ICP sensor.
The longer you ignore this problem, the greater the chance of your engine experiencing life-threatening issues.
How to Fix the P2291 Error Code
There are a few things you need to do to fix this problem. The most important thing is to inspect all of the components listed above so you can get a correct assessment of what needs work.
Fixing a Damaged ICP Sensor
The only way you can fix a damaged ICP sensor completely is to replace it with a new one.
Be sure to scan the ICP sensor first and compare it with the data listed in the table below. If the properties are off, something is wrong with the ICP sensor and it’s best to just replace it.
| PIDs | Values At Engine Cranking | Values At Engine Idling | Good-to-knows |
| ICP | 500 psi minimum | 600 to 800 psi | Normal ICP at idle is 600 to 800 psi. Injectors will NOT fire if the ICP reading is below 500 psi. Typically between 800 and 2,000 psi before the engine starts. |
| Desired ICP | — | — | Value should be reasonably close to the actual ICP with the engine running. ICP may trail ICP desired while the engine is cranking until the engine starts. |
| IPR duty cycle | up to 84% | ~ 30% | IPR duty cycle should start at 15% with the key “ON” and engine “OFF”. While cranking, the IPR duty cycle should rapidly increase to near peak (84%) until the engine starts or ~ 2,000 psi ICP is achieved. If the IPR duty cycle is significantly greater than 30% at idle, there is likely a leak in the high-pressure oil system (typically causes a long crank condition). The minimum IPR duty cycle is 15% (fully open); the maximum duty cycle is 85% (fully closed). |
Fixing Damaged Wiring
If the wires that lead to the ICP system are damaged, you will have to replace them.
This process is going to entail inspecting the entire wiring system associated with the ICP system and testing it out with an oscilloscope to see if the voltage properties are as they should be.
If some of the wires are dead, be sure to replace them with new ones. While doing so, make sure to match the OEM parts numbers between the old wires and the new ones.
Fixing Low Oil Levels
Sadly, encountering an oil leak isn’t all that unusual on some of these Powerstroke engines as they are large and tend to work under heavy loads most of the time.
To diagnose if a leak has actually occurred, you will have to check the oil pan, the oil pump gasket, the oil pump, the oil cooler gasket, the o rings, and the oil pan gasket for signs of leaks. If you do encounter leaks, the video below is going to help you fix them.
Dummy Plug Problems
If the dummy plugs cause any oil pressure-related problems, it’s best to replace them with the associated standpipes to prevent this problem from ever taking place again. Many Ford owners have been doing this for decades as it seems to do the trick.
It’s also a good idea to do an air test to prevent any oil leaks from going unnoticed as the dummy plugs can sometimes be just a single piece of the puzzle.
Either way, check out the video below for a detailed guide as to how to do it.
Turbocharger Wastegate Solenoid Problems
There are two possible problems correlated to turbocharger wastegate solenoid issues.
The first one is due to a computer error that causes the wastegate to open or close at the wrong time, which causes all the loud whistling noises and poor performance.
However, the problem can also be due to a faulty solenoid itself, which means that fixing this problem can be done by either resetting/replacing the computer that controls the solenoid, or the solenoid in its entirety.
Without going into all the technical bits, the following video outlines the entire process.
Powertrain Control Module Problems
If the problem lies within the PCM, things can get tricky. The most common one is the PCM connector circuit receiving either the wrong voltage or no voltage at all.
To fix this, be sure to do this:
- Wrong Voltage – Replace the circuit connecting the ICP and the PCM.
- No Voltage – Try to fix the PCM by updating it/re-setting it, or replace it altogether with an OEM PCM.
Mistakes to Avoid While Fixing the P2291 Code
The common mistakes most people make while trying to the P2291 Code are:
- Not using the owner’s manual for parts matching
- Not using an oscilloscope correctly
- Not inspecting the entire system for leaks
- Not using the correct PCM
If you do decide to replace the PCM, always go for one with the correct OEM part number as any PCM connection discrepancies are likely to cause more harm than good.
Tips to Prevent the P2291 Error Code
In order to avoid the P2291 code completely, follow these tips:
- Change the engine oil when needed.
- Stay on top of oil leaks.
- Replace the ICP during regular maintenance.
- Use OEM parts.
- Use the recommended oil.
- Replace your air, fuel, and oil filters regularly.
- Diagnose Check Engine Lights.
