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Engine Fault Code P0628

Fuel Pump A Control Circuit Low

Care Engine Code Reader
Engine Fault Code P0628 indicates a problem with the fuel pump control circuit. This specific code means that the Engine Control Module (ECM) has detected a low voltage or signal in the fuel pump A control circuit. This can affect the fuel pump`s ability to operate properly, which can lead to engine performance issues or even prevent the engine from starting.

Here are some common causes for this code:

1. Faulty Fuel Pump: The fuel pump itself may be malfunctioning.
2. Wiring Issues: There could be damaged or corroded wires in the fuel pump control circuit.
3. Bad Relay: The fuel pump relay might be faulty, preventing proper power to the pump.
4. ECM Issues: The Engine Control Module could be defective or have a software issue.

While P0628 generally means the same across many manufacturers, there can be slight variations in how different brands interpret or handle the code. Here are some alternative meanings or related codes based on specific manufacturers:

1. P0628 (Porsche): Similar interpretation but may relate to specific fuel system components in models like the Cayenne or 911.
2. P0628 (Mercedes): Often indicates issues with the fuel delivery system, and may require specific diagnostic procedures.
3. P0628 (Audi): Similar to Mercedes, but may also point to issues in the fuel pressure regulation system.
4. P0628 (Jaguar): May indicate a need for checking the fuel pump module and its connections.
5. P0628 (Land Rover): Could relate to both the fuel pump and the vehicle`s security system, affecting fuel delivery.

Always refer to the specific vehicle`s service manual for detailed diagnostics and repair procedures. If you`re experiencing this code, its best to check the wiring and connections first, then test the fuel pump and relay before considering ECM issues.
The Engine Fault Code P0628 indicates a problem with the fuel pump control circuit. This code means that the Engine Control Module (ECM) has detected a low voltage or an issue in the fuel pump circuit. Here are some common causes for this code, which can vary by manufacturer:

Common Causes:

1. Faulty Fuel Pump: The fuel pump itself may be malfunctioning or failing, causing it to draw less current than expected.

2. Wiring Issues: Damaged or corroded wiring in the fuel pump circuit can lead to low voltage readings. This includes broken wires or bad connections.

3. Bad Fuel Pump Relay: If the relay that controls the fuel pump is faulty, it may not supply the correct voltage, leading to this code.

4. ECM Issues: The Engine Control Module may have a fault or software issue that is causing it to misread the fuel pump`s performance.

5. Grounding Problems: Poor grounding in the circuit can lead to low voltage, affecting the fuel pump`s operation.

6. Fuel Pump Driver Module: In some vehicles, this module controls the fuel pump. If it fails, it can cause low voltage issues.

Manufacturer-Specific Considerations:

Porsche: Check for specific wiring harness issues, as Porsche models can have unique routing and connectors that may corrode.

Mini: Mini vehicles often have complex electrical systems; ensure that the battery voltage is adequate, as low voltage can affect all systems.

Mercedes: Mercedes models may have additional layers of diagnostics in their systems, so its essential to check for other related codes.

Audi: Audi vehicles often use a fuel pump control module, which may need to be tested separately.

Jaguar: In Jaguars, the issue could also stem from the body control module affecting the fuel pump circuit.

Land Rover: Land Rover vehicles may have specific software updates or recalls that address fuel pump issues, so checking for updates is crucial.



If you encounter code P0628, start by checking the fuel pump and its circuit, including wiring and connectors. Depending on the make and model, the specific components involved may vary, so consulting a repair manual or a professional mechanic familiar with your vehicle is a good idea.
Fixing the Engine Fault Code P0628, which indicates a `Fuel Pump A Control Circuit Low,` can vary depending on the vehicle make and model. Heres a general guide, along with specific notes for European brands like Porsche, Mini, Mercedes, Audi, Jaguar, and Land Rover.

General Steps to Fix P0628:

1. Check the Code Again: Use an OBD-II scanner to confirm the code and see if there are any other related codes.

2. Inspect the Wiring and Connectors: Look for any damaged wires or loose connections in the fuel pump circuit. Pay special attention to the connectors leading to the fuel pump.

3. Test the Fuel Pump Relay: The relay controls power to the fuel pump. Swap it with a similar relay in the fuse box to see if the problem persists.

4. Check the Fuel Pump Fuse: Ensure the fuse for the fuel pump is not blown. Replace if necessary.

5. Test the Fuel Pump: If the wiring and relay are fine, the fuel pump itself may be faulty. You can test it by applying direct power to the pump to see if it operates.

6. Inspect the Fuel Pump Control Module: Some vehicles have a control module that regulates the fuel pump. If this module fails, it could cause the P0628 code.

7. Check the Ground Connection: Ensure that the ground connection for the fuel pump is secure and free of corrosion.

8. Clear the Codes: After making repairs, clear the fault codes and take the vehicle for a test drive to see if the code returns.

Manufacturer-Specific Notes:

Porsche: Check the DME (Digital Motor Electronics) as it controls the fuel pump. Ensure software is updated, as sometimes updates can fix control issues.

Mini: Look for issues with the fuel pump control module, especially if you have a newer model. It can sometimes be reset with a scanner.

Mercedes: The fuel pump relay is often integrated into the SAM (Signal Acquisition and Actuation Module). If the relay is good, you may need to check the SAM.

Audi: Some Audis have dual fuel pumps. Ensure both are functioning and check the wiring harness for wear.

Jaguar: Jaguars may have issues with the fuel pump module located in the fuel tank. If the module is faulty, replacement may be necessary.

Land Rover: Similar to Jaguar, Land Rovers often have a fuel pump module in the tank. Additionally, check for issues with the Terrain Response system if equipped.



Fixing P0628 involves a series of checks and tests. Start with the basics like wiring and fuses before moving on to more complex components like the fuel pump or control module. Always refer to the specific service manual for your vehicle for more detailed instructions. If you`re unsure or uncomfortable with any steps, its best to consult a professional mechanic.
Driving with a P0628 code, which indicates a low fuel pump control circuit voltage, is generally not safe. Heres a breakdown of what it means and the potential risks, along with some manufacturer-specific insights:

General Risks:
1. Fuel Delivery Issues: The low voltage may prevent the fuel pump from operating correctly, leading to insufficient fuel delivery. This can cause the engine to stall or not start at all.
2. Engine Performance Problems: If the fuel pump isn`t working properly, you might experience poor acceleration, rough idling, or misfires.
3. Safety Hazards: Stalling in traffic can create dangerous situations, especially at high speeds or in busy areas.

Manufacturer-Specific Insights:
1. Porsche: In Porsches, a malfunctioning fuel pump can lead to performance issues and may trigger additional warning lights. It`s best to address this code quickly.
2. Mini: For Mini vehicles, the fuel pump is crucial for engine performance. Ignoring this code can lead to more severe engine problems.
3. Mercedes: In Mercedes models, the fuel system is complex. A low voltage issue can affect other systems, so it`s advisable to have it checked out.
4. Audi: Audi cars often have advanced fuel management systems. A P0628 code could indicate a failing fuel pump relay or wiring issues that need immediate attention.
5. Jaguar: Jaguars can be sensitive to fuel delivery problems. Ignoring the P0628 code may lead to more costly repairs down the line.
6. Land Rover: In Land Rovers, fuel pump issues can lead to off-road performance problems as well. It`s best to diagnose and fix it as soon as possible.


In all cases, it is best to avoid driving the vehicle until the issue is resolved. If you see a P0628 code, have a mechanic check it out to ensure your car is safe and running properly.

OBD Codes Explained

Engine Codes

P is for PowerTrain - Engine and Transmission.

P0 Indicates Generic Powertrain Codes

P0 Codes indicate problems with the powertrain and are common for all vehicles using the OBD-II Standard.

P1 Enhanced Manufacturer Specific Codes

P1 Codes are specific to manufacturers.

Sub-System

The 3rd Digit indicates the Sub-System

1 – Emission Management

2 – Injector Circuit

3 – Ignition

4 – Emission Control

5 – Vehicle Speed and Idle

6 – Computer and Output

7 – Transmission

8 – Transmission

9 – Reserved

0 – Reserved

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