What is OBD-II Code P00CA – Fuel Pressure Regulator A Solenoid Supply Voltage Control Circuit High

What is OBD-II Code P00CA – Fuel Pressure Regulator A Solenoid Supply Voltage Control Circuit High

As a mechanic, one of the most common diagnostic trouble codes (DTCs) you’ll come across when dealing with fuel systems is P00CA. This code refers to a Fuel Pressure Regulator A Solenoid Supply high voltage control circuit. In this comprehensive guide, we’ll explain what P00CA means, its causes, symptoms, and how to fix it.

Understanding OBD-II Codes

The On-Board Diagnostics (OBD) system installed in modern automobiles is a powerful tool that collects data and stores trouble codes, which are identified by a letter followed by four numbers. These codes are used as reference points to help diagnose vehicle malfunctions, and they can be easily read using a code reader or scanner. Once you’ve determined the code being thrown by your vehicle, you can move on to the process of eliminating the problem.

What is P00CA and What Does It Mean?

P00CA is a trouble code that relates to the fuel system of your vehicle. It is specifically related to the voltage control circuit at the source of the solenoid supply responsible for regulating fuel pressure. This code will typically be seen in vehicles with a fuel injection system. When the fuel pressure regulator’s electrical control circuit begins to act up, causing the voltage to rise above its set point, the P00CA code is triggered.

When this code is thrown, it means that the fuel pressure regulator has detected a malfunction in the control solenoid. This will cause the fuel system to malfunction, leading to a problematic and potentially hazardous situation. It’s important to note that this is only one possible cause of P00CA, and there are other reasons why this code may be thrown.

Causes of P00CA

Like many OBD-II codes, there are several possible causes of P00CA. The most common of these include:

1. Faulty Fuel Pressure Regulator Solenoid: A faulty solenoid can cause voltage levels to rise higher than their set limit, triggering the P00CA code.

2. Wiring Issues: Electrical problems within the solenoid circuit can cause the P00CA code to be set. Frayed wiring, loose connections, and corroded contacts can all lead to electrical issues.

3. Faulty Fuel Pressure Regulator: If the fuel pressure regulator itself is causing high voltage levels, it could be the cause of P00CA.

Symptoms of P00CA

When P00CA is thrown, many drivers will notice symptoms that indicate a problem with their fuel system. Some common symptoms of P00CA include:

1. Decreased Engine Performance: A faulty fuel pressure regulator is often associated with decreased engine performance.

2. Reduced Fuel Efficiency: A malfunctioning fuel pressure regulator can cause your vehicle to use more fuel than normal.

3. Difficulty Starting Your Engine: If the P00CA code is left unaddressed long enough, it can lead to difficulty starting your engine.

How to Fix P00CA

Fortunately, fixing P00CA is relatively straightforward, and most experienced mechanics will be able to handle the problem easily. Generally, the steps required to fix P00CA include:

1. Diagnose the Problem: Use a scanner to determine the specific error code and which system it is coming from.

2. Check the Wiring and Connections: Ensure that all connections and wiring within the fuel pressure regulator solenoid circuit are secure and free of corrosion.

3. Inspect the Fuel Pressure Regulator: Check the regulator for any visible sign of damage, and replace it if required.

4. Clear the Codes: Use your scanner or code reader to clear the error codes, ensuring that the problem has been solved.


If you’ve been struggling with the P00CA code in your vehicle, you’re now equipped with the knowledge to fix the issue. By following the steps outlined in this guide, you can quickly diagnose and repair the problem, ensuring that your fuel system is functioning correctly and keeping you safe on the road.


1. Can a bad fuel pressure regulator cause other codes to be triggered?

Yes, a malfunctioning fuel pressure regulator can cause other OBD-II codes to be set in your vehicle.

2. How can I prevent P00CA from occurring?

Regular maintenance and inspection of your fuel system, including the fuel pressure regulator, will help prevent the P00CA code from being set.

3. Will P00CA trigger a check engine light?

Yes, P00CA will typically trigger a check engine light to appear on your vehicle’s dashboard.

4. Can a faulty fuel pressure regulator cause my vehicle to fail an emissions test?

Yes, in some cases, a malfunctioning fuel pressure regulator can cause your vehicle to fail an emissions test.

5. How long does it take to fix P00CA?

Fixing the P00CA code can take anywhere from a couple of minutes to a few hours, depending on the severity of the problem and the specific cause of the code.

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