P008A Code: Low Pressure Fuel System Pressure – Too Low

Your vehicle’s on-board diagnostics (OBD) monitors your vehicle’s performance through a network of sensors and alerts you of potential issues.

Trouble codes, such as the P008A, help you understand the nature of a potential problem within your vehicle. Find out what the P008A code means and learn more about its symptoms and possible causes with this brief guide.

What Does the P008A Code Mean?

Diagnostic trouble code (DTC) P008A stands for “Low Pressure Fuel System Pressure- Too Low.” This trouble code sets when the powertrain control module (PCM) has detected that the fuel pressure is too low within the low fuel system. In some cases, low fuel volume or insufficient flow may also trigger this code.

Note: The definition of code P008A may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

Often, this code pops up in diesel-powered vehicles. Diesel engines rely heavily on a high-pressure injection pump to provide the high pressure needed to atomize the fuel efficiently. The low-pressure fuel system supplies the high-pressure fuel injection pump with fuel from the fuel tank.

Gas-powered vehicles may also exhibit code P008A. In a typical modern, returnless gasoline fuel system, a control module (usually the fuel pump control module) regulates an in-tank fuel pump to control fuel pressure. A fuel pressure sensor provides the fuel pump control module with feedback regarding system operation. The fuel pump control module communicates with the PCM over a data network.

The PCM monitors the operation of the fuel system closely because a lot of factors may hamper the system’s operations and performance. For example, in a diesel fuel system, additional air introduced into the system by an injection pump or injector may cause several issues. Fuel leaks and contaminated fuel may also affect the fuel pump and other low-pressure fuel system components.

Low Pressure vs. High Pressure

Code P008A generally only occurs on common rail fuel systems where the mechanical high pressure fuel pump is fed by an electric in-tank low pressure fuel pump.

But the P008A code is most common on systems where the low pressure system is a closed loop system, meaning that there is a low fuel system pressure sensor and a module that controls the pressure based on that low pressure sensor input.

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Pro Tip: Early Duramax diesels (GM) didn’t have an in-tank pump, but even the later Duramax platforms that do have an in-tank pump don’t include this DTC in their code list and won’t set it. Likewise, with Ford Common Rail Injection Powerstroke engines, this code isn’t listed even though there is a low pressure fuel system feeding the high pressure pump.

But what about Gasoline Direct Injection vehicles (GDI)? Well, older (2014) Hyundai GDI systems don’t have a closed loop low pressure fuel system, and neither do Hondas. Their low pressure fuel systems have an in-tank regulator rather than having a module controlling the pump.

The way computers “think” is that, when there is a closed loop system, no matter what  system it is, the computer sets a “target” pressure or speed, or whatever, and applies outputs to reach that target. If it can’t reach the target, it sets the code. That’s what this code means.

On a 2019 Toyota Camry, it’s described this way:

Actual low side fuel pressure is less than the target pressure for a certain period of time.

What are the Possible Causes of the P008A Code?

There are several possible reasons why a DTC like P008A sets. After all, DTCs indicate the potential location and nature of the issue, not the root cause. Listed below are some of the likely triggers of the P008A code:

• Fuel pressure regulator or fuel volume control valve failure
• Fuel pump failure
• PCM failure
• Wiring issue
• Fuel injector failure
• Contaminated fuel
• Fuel filter blockage
• Restricted fuel line
• Aerated fuel (diesel engines)
• Damaged fuel pressure sensor
• FPCM failure
• Low fuel level

What are the Common Symptoms of the P008A Code?

When a trouble code sets, the vehicle’s computer sends a signal to illuminate the check engine light or the malfunction indicator lamp (MIL). For many trouble codes, other symptoms may also be present. However, other trouble codes may not manifest signs other than an activated check engine light. Listed below are some of the common symptoms of the code P008A:

• Check engine light or malfunction indicator lamp (MIL) on
• Decreased engine performance
• Increased fuel consumption
• Increased emissions
• Unusual throttle response
• Abnormal engine noise
• Engine hard start
• Noticeable engine smoke on start up

How to Diagnose the P008A Code

Finding out what triggered a DTC to set can be a challenging and time-consuming task. Proper diagnosis requires the vehicle owner or a mechanic to narrow the problem down from a list of possible causes.

With the right tools and information, addressing the main issue behind P008A is possible. Vehicle-specific repair manuals and databases are the best sources of information, as they contain detailed instructions and helpful illustrations. Other sources are also available online, such as how-to videos and informative blog posts.

How to Fix the P008A Code

Aside from several possible causes, fixing trouble codes is further complicated by the fact that vehicles are made differently, depending on the manufacturer. The solution to P008A on Mercedes-Benz vehicles may not work the same way to address the P008A on Ford vehicles.

Repair manuals and databases may be helpful to the seasoned DIYer. However, if you don’t know how to troubleshoot and fix OBD codes, it’s best to have a professional mechanic or technician do the repairs for you.

Other Notes About P008A

It’s important to keep your fuel system working properly to avoid more problems down the line. Consistently low fuel pressures may cause issues in the future, especially for diesel engines. Once you encounter the P008A code, it is highly recommended that troubleshooting and repairs be done immediately.

Common solutions to the code P008A include replacing the fuel filter or the fuel pump. However, these solutions may not work in all cases. Determining the root cause of the issue is extremely important.

Products Mentioned in this Guide

Fuel Pressure Regulator Fuel Pump Fuel Injector Fuel Filter Fuel Pressure Sensor Engine Control Module