What Does BMW Error Code 651b Indicate?

The BMW 651b code typically indicates an issue with the fuel supply system, often related to the fuel pump or fuel level sensors in vehicles with saddle-shaped fuel tanks. Addressing this promptly is crucial to prevent drivability issues and potential engine damage, consulting AutoExplain.com for remote expert assistance can streamline the diagnostics and repair process. Get immediate support via WhatsApp (+84)967469410 or Email [email protected].

1. What is BMW Code 651b and How Does it Affect My Car?

BMW code 651b often relates to a fuel delivery issue, particularly in models with a saddle-shaped fuel tank where fuel transfer between the tank’s two sides is crucial. This code can mean that the fuel pump isn’t getting enough fuel, or that the fuel level sensors are malfunctioning, leading to inaccurate readings and potential engine stalling.

Understanding the Fuel System Dynamics in BMWs

Many BMWs, particularly those with xDrive (all-wheel drive), use a saddle-shaped fuel tank that straddles the driveshaft. This design splits the tank into two compartments, necessitating a system to transfer fuel from one side to the other to ensure the fuel pump, located on one side, always has an adequate supply. The key components involved are:

• Fuel Pump: Located on one side of the tank, responsible for delivering fuel to the engine.
• Fuel Level Sensors: Two sensors, one in each tank compartment, provide readings to the car’s computer (ECU) about fuel levels.
• Suction Jet Pump (or Fuel Transfer Pump): This pump transfers fuel from the passive side of the tank to the active side where the main fuel pump is located. It operates based on the Venturi principle, using the flow of fuel returning from the engine to create suction.

How the 651b Code Manifests

The 651b code can arise from several issues within this system:

• Malfunctioning Suction Jet Pump: If this pump fails, fuel won’t be transferred from the passive side to the active side. This can lead to the fuel pump running dry even if there’s fuel in the tank, especially when the fuel level is low.
• Faulty Fuel Level Sensors: Inaccurate readings from these sensors can confuse the ECU, leading to incorrect fuel level estimations and potentially triggering the code.
• Fuel Pump Issues: A failing or weak fuel pump may struggle to maintain adequate fuel pressure, especially when the fuel level in the active side is low.
• Wiring or Electrical Problems: Issues with the wiring or connectors to the fuel pump, fuel level sensors, or suction jet pump can also trigger the code.

Symptoms Associated with the 651b Code

• Engine Stalling: Particularly when the fuel level is low, the engine may stall due to fuel starvation.
• Difficulty Starting: The car may crank but fail to start, especially after running low on fuel.
• Inaccurate Fuel Gauge: The fuel gauge may display incorrect readings.
• Reduced Performance: The engine may lack power, especially during acceleration.
• Check Engine Light: The check engine light will illuminate on the dashboard.

Why is Prompt Diagnosis Important?

Ignoring the 651b code can lead to several problems:

• Engine Damage: Running the fuel pump dry can damage it, requiring costly replacement.
• Drivability Issues: Stalling and poor performance can make the car unreliable and unsafe.
• Inaccurate Fuel Readings: Inaccurate fuel gauge readings can lead to running out of gas unexpectedly.

Expert Remote Assistance from AutoExplain.com

Diagnosing fuel system issues, especially in complex systems like those in BMWs, can be challenging. AutoExplain.com offers remote expert assistance to help you pinpoint the exact cause of the 651b code and guide you through the repair process. Contact us via WhatsApp (+84)967469410 or Email [email protected] for immediate support.

2. What are the Common Causes of the 651b BMW Code?

The 651b Bmw Code can stem from several issues within the fuel delivery system, including a faulty suction jet pump, malfunctioning fuel level sensors, problems with the fuel pump itself, or electrical issues. Addressing these issues quickly can prevent more significant problems. AutoExplain.com offers remote diagnostic and repair support to help you resolve this issue efficiently.

In-Depth Look at the Causes

1. Faulty Suction Jet Pump (Fuel Transfer Pump):
   • Function: The suction jet pump transfers fuel from the passive side of the fuel tank to the active side where the fuel pump is located.
   • Failure Symptoms: If the suction jet pump fails, fuel remains on the passive side, even as the active side runs dry. This is particularly noticeable when the fuel level is low (less than half a tank).
   • Troubleshooting: Check the pump for proper operation. Listen for its sound when the fuel level is low. If there’s no sound, it may be faulty. You can also test its functionality using diagnostic tools like INPA to monitor fuel levels on both sides of the tank.
2. Malfunctioning Fuel Level Sensors:
   • Function: Fuel level sensors (one in each side of the tank) provide readings to the ECU, indicating the amount of fuel in each compartment.
   • Failure Symptoms: Inaccurate readings from these sensors can confuse the ECU, leading to incorrect fuel level estimations. This can trigger the 651b code.
   • Troubleshooting: Use INPA to read the values from both fuel level sensors. Compare the readings with the actual fuel level in the tank. If the readings are significantly different, the sensors may be faulty.
3. Fuel Pump Issues:
   • Function: The fuel pump delivers fuel from the tank to the engine.
   • Failure Symptoms: A failing or weak fuel pump may struggle to maintain adequate fuel pressure, especially when the fuel level in the active side is low.
   • Troubleshooting: Check the fuel pump’s operation using INPA to monitor pump speed and current. Low current with high speed may indicate the pump is drawing air, suggesting fuel starvation. Also, check the low-pressure fuel sensor to ensure it’s within the specified range (around 72 PSI).
4. Wiring or Electrical Problems:
   • Function: Proper wiring and connections are essential for the fuel pump, fuel level sensors, and suction jet pump to function correctly.
   • Failure Symptoms: Issues with wiring, such as corrosion, loose connections, or damaged wires, can disrupt the electrical signals, triggering the 651b code.
   • Troubleshooting: Inspect the wiring and connectors for any signs of damage or corrosion. Use a multimeter to check for proper voltage and continuity in the circuits.

Diagnostic Steps Using INPA

INPA (BMW diagnostic software) is a valuable tool for diagnosing fuel system issues. Here’s how to use it to troubleshoot the 651b code:

1. Read Fuel Level Sensor Values:

   • Connect to the JBBF/JBE (Body/Junction Box Passenger) module.
   • Go to F5 (Status) -> F3 (Status Sensors).
   • Check the readings of both fuel level sensors. Compare these readings with the actual fuel level in the tank.

2. Check Fuel Pump Operation:

   • Connect to the EKPS (Fuel Pump Module).
   • Go to F5 (Status) and review all status screens.
   • Monitor pump current and RPM. Low current with high RPM suggests the pump is drawing air.

3. Monitor Low-Pressure Fuel Sensor:

   • Connect to the DME (Digital Motor Electronics).
   • Go to F5 (Status) and look for a menu option related to the low-pressure fuel sensor.
   • Check the fuel pressure reading. It should be around 72 PSI.

Real-World Scenario and Solution

Imagine a BMW 335i owner experiencing the 651b code. They’ve replaced the fuel pressure regulator and fuel pump, but the car still cranks without starting. Using INPA, they notice the fuel pump speed is high, but the current is low. This suggests the pump is drawing air. Further inspection reveals the suction jet pump is faulty, preventing fuel from being transferred from the left side of the tank to the right. Replacing the suction jet pump resolves the issue.

How AutoExplain.com Can Help

AutoExplain.com provides remote expert assistance to help you diagnose and repair the 651b code. Our services include:

• Remote Diagnostics: We can remotely connect to your car’s computer to read codes, monitor sensor values, and help pinpoint the exact cause of the problem.
• Step-by-Step Repair Guidance: We provide detailed instructions and diagrams to guide you through the repair process.
• Expert Advice: Our team of experienced BMW technicians can answer your questions and provide expert advice on the best course of action.

Don’t waste time and money on unnecessary repairs. Contact AutoExplain.com via WhatsApp (+84)967469410 or Email [email protected] for fast, accurate, and reliable remote assistance.

3. Step-by-Step Guide to Diagnosing the 651b Code on Your BMW

Diagnosing the 651b code on your BMW involves systematically checking the fuel delivery system. This guide covers everything from initial inspections to advanced diagnostics using tools like INPA. AutoExplain.com offers expert remote support to help you navigate this process, ensuring accurate and efficient troubleshooting.

Initial Inspection

Before diving into advanced diagnostics, perform these basic checks:

1. Fuel Level: Ensure there is enough fuel in the tank. A low fuel level can trigger the code, especially if the suction jet pump is weak.
2. Fuel Cap: Check the fuel cap to ensure it is properly tightened. A loose fuel cap can cause pressure issues in the fuel system.
3. Visual Inspection: Inspect the fuel lines, fuel pump, and fuel filter for any signs of leaks or damage.

Using INPA for Advanced Diagnostics

INPA (BMW diagnostic software) is essential for diagnosing the 651b code. Here’s how to use it effectively:

1. Connect to the Vehicle:

   • Connect the INPA interface to your BMW’s OBD-II port.
   • Open the INPA software on your computer.
   • Select your vehicle model and chassis.

2. Read and Clear Fault Codes:

   • Navigate to the DME (Digital Motor Electronics) module.
   • Select “Error Memory” or “Fault Codes” to read the stored codes.
   • Note all codes, especially the 651b code, and any related fuel system codes.
   • Clear the codes and restart the engine to see if the 651b code returns.

3. Monitor Fuel Level Sensors:

   • Navigate to the JBBF/JBE (Body/Junction Box Passenger) module.
   • Select “F5 Status” -> “F3 Status Sensors”.
   • Check the readings from both fuel level sensors.
   • Compare the readings to the actual fuel level in the tank. Significant discrepancies indicate a faulty sensor.

4. Check Fuel Pump Operation:

   • Navigate to the EKPS (Fuel Pump Module).
   • Select “F5 Status” and review all status screens.
   • Monitor the fuel pump current and RPM.
   • Low current with high RPM suggests the pump is drawing air, indicating fuel starvation.

5. Monitor Low-Pressure Fuel Sensor:

   • Navigate to the DME (Digital Motor Electronics) module.
   • Select “F5 Status” and look for a menu option related to the low-pressure fuel sensor.
   • Check the fuel pressure reading. It should be around 72 PSI.

Testing the Suction Jet Pump

The suction jet pump is a common culprit for the 651b code. Here’s how to test it:

1. Listen for Pump Operation:
   • With the engine running and the fuel level low (less than half a tank), listen for the sound of the suction jet pump operating. It should make a noticeable whirring or buzzing sound. If you don’t hear it, the pump may be faulty.
2. Check Fuel Transfer:
   • Remove the fuel level sensor on the passive side of the tank.
   • With the engine running, observe if fuel is being transferred to the active side. If not, the suction jet pump is likely faulty.
3. Use INPA to Monitor Fuel Levels:
   • Monitor the fuel levels on both sides of the tank using INPA.
   • If the fuel level on the passive side remains high while the active side is low, the suction jet pump is not working correctly.

Electrical Testing

If the suction jet pump and fuel level sensors appear to be functioning, check the electrical connections:

1. Check Wiring and Connectors:
   • Inspect the wiring and connectors for any signs of damage, corrosion, or loose connections.
   • Clean corroded connectors with electrical contact cleaner.
2. Test Voltage and Continuity:
   • Use a multimeter to check for proper voltage and continuity in the circuits to the fuel pump, fuel level sensors, and suction jet pump.
   • Consult the BMW wiring diagrams for your specific model to identify the correct wires and pin locations.

Example Scenario and Troubleshooting

A BMW owner experiences the 651b code and notices the fuel gauge is inaccurate. Using INPA, they find one of the fuel level sensors is reading significantly lower than the actual fuel level. They replace the faulty fuel level sensor, clear the code, and the problem is resolved.

How AutoExplain.com Enhances the Diagnostic Process

AutoExplain.com offers expert remote assistance to guide you through each step of the diagnostic process. Our services include:

• Remote Diagnostics: We remotely connect to your car’s computer to read codes, monitor sensor values, and help pinpoint the exact cause of the problem.
• Step-by-Step Guidance: We provide detailed instructions and diagrams to guide you through each step of the diagnostic process.
• Expert Advice: Our team of experienced BMW technicians can answer your questions and provide expert advice on the best course of action.

Don’t get stuck with complex diagnostics. Contact AutoExplain.com via WhatsApp (+84)967469410 or Email [email protected] for fast, accurate, and reliable remote assistance.

4. How to Fix the 651b Code on Your BMW: A Comprehensive Guide

Fixing the 651b code on your BMW involves addressing the root cause within the fuel delivery system. This comprehensive guide provides step-by-step instructions for repairing or replacing faulty components, including the suction jet pump, fuel level sensors, and fuel pump. AutoExplain.com offers expert remote support to ensure you complete these repairs effectively.

Step 1: Replacing the Suction Jet Pump

If the suction jet pump is faulty, follow these steps to replace it:

1. Safety First:
   • Disconnect the negative terminal of the battery to prevent electrical shorts.
   • Work in a well-ventilated area and avoid open flames.
2. Access the Fuel Tank:
   • The suction jet pump is located inside the fuel tank. You may need to remove the rear seat or access the tank from underneath the car, depending on your BMW model.
   • Consult your BMW repair manual for specific instructions.
3. Drain the Fuel:
   • Drain as much fuel as possible from the tank to make the job easier and safer. Use a fuel siphon or a fuel pump to remove the fuel.
4. Remove the Fuel Pump Assembly:
   • Disconnect the fuel lines and electrical connectors from the fuel pump assembly.
   • Carefully remove the fuel pump assembly from the tank.
5. Replace the Suction Jet Pump:
   • The suction jet pump is usually attached to the fuel pump assembly.
   • Disconnect the old suction jet pump and install the new one. Ensure all connections are secure.
6. Reinstall the Fuel Pump Assembly:
   • Carefully reinstall the fuel pump assembly into the tank.
   • Reconnect the fuel lines and electrical connectors.
7. Refill the Fuel Tank:
   • Add fuel back into the tank. Start with a small amount (e.g., 1 gallon) to check for leaks.
8. Reconnect the Battery:
   • Reconnect the negative terminal of the battery.
9. Test the Repair:
   • Start the engine and let it run for a few minutes.
   • Use INPA to monitor fuel levels on both sides of the tank. Ensure the suction jet pump is transferring fuel correctly.
   • Clear the 651b code and check if it returns.

Step 2: Replacing Fuel Level Sensors

If the fuel level sensors are faulty, follow these steps to replace them:

1. Safety First:
   • Disconnect the negative terminal of the battery.
2. Access the Fuel Tank:
   • Follow the same steps as above to access the fuel tank.
3. Locate the Fuel Level Sensors:
   • There are two fuel level sensors, one on each side of the tank.
   • They are usually attached to the fuel pump assembly or mounted separately in the tank.
4. Disconnect the Old Sensors:
   • Disconnect the electrical connectors from the old fuel level sensors.
   • Carefully remove the sensors from the tank.
5. Install the New Sensors:
   • Install the new fuel level sensors into the tank.
   • Ensure they are properly seated and secured.
   • Reconnect the electrical connectors.
6. Reinstall the Fuel Pump Assembly:
   • Carefully reinstall the fuel pump assembly into the tank.
   • Reconnect the fuel lines and electrical connectors.
7. Refill the Fuel Tank:
   • Add fuel back into the tank.
8. Reconnect the Battery:
   • Reconnect the negative terminal of the battery.
9. Test the Repair:
   • Start the engine and let it run for a few minutes.
   • Use INPA to monitor the fuel level readings from both sensors. Ensure they are accurate.
   • Clear the 651b code and check if it returns.

Step 3: Addressing Fuel Pump Issues

If the fuel pump is failing, consider these steps:

1. Check Fuel Pump Relay and Fuses:
   • Locate the fuel pump relay and fuse in the fuse box.
   • Check the fuse for continuity. Replace if blown.
   • Test the relay using a multimeter. Replace if faulty.
2. Replace the Fuel Pump (if necessary):
   • Follow the steps above to access the fuel tank and remove the fuel pump assembly.
   • Disconnect the old fuel pump from the assembly and install the new one.
   • Reinstall the fuel pump assembly and reconnect all lines and connectors.
   • Test the repair as described above.

Example Scenario

A BMW owner replaces the suction jet pump, but the 651b code persists. They then use INPA to monitor the fuel level sensors and find one is giving erratic readings. Replacing the faulty fuel level sensor resolves the issue.

AutoExplain.com Enhances Your Repair Efforts

AutoExplain.com offers expert remote assistance to guide you through each step of the repair process. Our services include:

• Remote Diagnostics: We remotely connect to your car’s computer to confirm the diagnosis and identify any additional issues.
• Step-by-Step Guidance: We provide detailed instructions and diagrams to guide you through each step of the repair process.
• Expert Advice: Our team of experienced BMW technicians can answer your questions and provide expert advice on the best course of action.

Don’t struggle with complex repairs. Contact AutoExplain.com via WhatsApp (+84)967469410 or Email [email protected] for fast, accurate, and reliable remote assistance.

5. Can I Prevent the 651b Code on My BMW? Proactive Maintenance Tips

Preventing the 651b code on your BMW involves regular maintenance and attention to the fuel system. Proactive care can help you avoid costly repairs and ensure your BMW runs smoothly. AutoExplain.com provides expert advice and remote support to help you maintain your vehicle’s fuel system effectively.

Key Maintenance Tips to Prevent the 651b Code

1. Maintain Adequate Fuel Levels:
   • Avoid running your BMW with a consistently low fuel level (below 1/4 tank). This can strain the fuel pump and suction jet pump, potentially leading to premature failure.
2. Regular Fuel Filter Replacement:
   • Replace the fuel filter according to the manufacturer’s recommended service interval. A clogged fuel filter can restrict fuel flow, causing the fuel pump to work harder and potentially triggering the 651b code.
3. Fuel Injector Cleaning:
   • Have your fuel injectors cleaned periodically to ensure they are delivering fuel efficiently. Dirty fuel injectors can disrupt the fuel system’s balance and contribute to fuel delivery issues.
4. Check Fuel Lines and Connections:
   • Regularly inspect the fuel lines and connections for any signs of leaks, cracks, or corrosion. Address any issues promptly to prevent fuel pressure problems.
5. Use Quality Fuel:
   • Use high-quality fuel from reputable gas stations. Poor-quality fuel can contain contaminants that clog the fuel filter and damage the fuel pump.
6. Monitor Fuel System Performance with INPA:
   • Periodically use INPA to monitor the fuel system’s performance, including fuel level sensor readings, fuel pump current, and fuel pressure. This can help you detect potential issues early on.
7. Address Fuel System Issues Promptly:
   • If you notice any symptoms of fuel system problems, such as difficulty starting, rough idling, or reduced performance, address them promptly. Ignoring these issues can lead to more severe problems and trigger the 651b code.

Maintenance Schedule for Fuel System Components

Component	Recommended Service Interval
Fuel Filter	Every 30,000 miles or as recommended by BMW
Fuel Injector Cleaning	Every 50,000 miles or as needed
Fuel Line Inspection	Every 12 months or during routine maintenance
Fuel Tank Inspection	Every 2-3 years, especially for older vehicles
Fuel Pump	Inspect during routine maintenance; replace as needed
Fuel Level Sensors	Monitor with INPA; replace if readings are inaccurate
Suction Jet Pump	Check during fuel pump service; replace if not functioning

Benefits of Proactive Maintenance

• Avoid Costly Repairs: Regular maintenance can prevent major fuel system failures, saving you money on expensive repairs.
• Improve Fuel Efficiency: A well-maintained fuel system ensures optimal fuel delivery, improving fuel efficiency.
• Enhance Vehicle Performance: A healthy fuel system ensures smooth engine operation and optimal performance.
• Increase Vehicle Longevity: Proactive maintenance can extend the life of your BMW by preventing wear and tear on critical fuel system components.

How AutoExplain.com Supports Your Maintenance Efforts

AutoExplain.com offers expert remote assistance to help you maintain your BMW’s fuel system effectively. Our services include:

• Remote Diagnostics: We can remotely connect to your car’s computer to monitor fuel system parameters and detect potential issues.
• Maintenance Guidance: We provide detailed instructions and advice on how to perform routine maintenance tasks.
• Expert Support: Our team of experienced BMW technicians can answer your questions and provide expert advice on maintaining your vehicle.

Example Scenario

A BMW owner follows a regular maintenance schedule, including fuel filter replacement and fuel injector cleaning. They also use INPA to monitor the fuel level sensor readings and detect a slight discrepancy. They replace the sensor before it fails completely, preventing the 651b code from occurring.

Don’t wait for problems to arise. Contact AutoExplain.com via WhatsApp (+84)967469410 or Email [email protected] for proactive maintenance guidance and expert support.

6. What are the Costs Associated with Fixing the 651b Code on a BMW?

Fixing the 651b code on a BMW can involve various costs depending on the faulty component and whether you choose to DIY or hire a professional. Understanding these costs can help you budget effectively and make informed decisions. AutoExplain.com offers cost-effective remote support to help you minimize expenses while ensuring quality repairs.

Cost Breakdown by Component

1. Suction Jet Pump (Fuel Transfer Pump):

   • Part Cost: $50 – $200 (depending on the brand and model).
   • DIY Labor: 2-4 hours (if you have experience).
   • Professional Labor: $200 – $400 (depending on the shop rate).
   • Total Cost (DIY): $50 – $200
   • Total Cost (Professional): $250 – $600

2. Fuel Level Sensors:

   • Part Cost: $80 – $250 per sensor (you may need to replace both).
   • DIY Labor: 2-3 hours.
   • Professional Labor: $150 – $300.
   • Total Cost (DIY): $80 – $500
   • Total Cost (Professional): $230 – $800

3. Fuel Pump:

   • Part Cost: $150 – $500 (depending on the brand and model).
   • DIY Labor: 3-5 hours.
   • Professional Labor: $300 – $600.
   • Total Cost (DIY): $150 – $500
   • Total Cost (Professional): $450 – $1100

4. Wiring and Electrical Issues:

   • Part Cost: $0 – $50 (for connectors, wiring, or fuses).
   • DIY Labor: 1-3 hours (depending on the complexity).
   • Professional Labor: $100 – $300.
   • Total Cost (DIY): $0 – $50
   • Total Cost (Professional): $100 – $350

Additional Costs to Consider

• Diagnostic Fees: Some shops charge a diagnostic fee (typically $50 – $150) to identify the cause of the 651b code. AutoExplain.com can help you avoid this fee with our remote diagnostic services.
• INPA Software and Cable: If you plan to DIY, you may need to purchase INPA software and a compatible cable (approximately $50 – $100).
• Tools: Ensure you have the necessary tools, such as a socket set, wrench set, multimeter, and fuel line disconnect tool.
• Unexpected Issues: Be prepared for unexpected issues that may arise during the repair process, such as broken connectors or damaged fuel lines.

DIY vs. Professional Repair

• DIY: Offers significant cost savings, especially on labor. However, it requires technical knowledge, experience, and the right tools.
• Professional Repair: Provides expertise and assurance of quality workmanship. However, it can be more expensive due to labor costs.

How AutoExplain.com Minimizes Your Costs

AutoExplain.com offers cost-effective remote support to help you fix the 651b code while minimizing expenses:

• Remote Diagnostics: We can remotely diagnose the issue, saving you the diagnostic fee at a repair shop.
• DIY Guidance: We provide step-by-step instructions and expert advice to help you perform the repairs yourself, saving on labor costs.
• Parts Recommendations: We can recommend reliable and affordable parts, helping you avoid overpriced or unnecessary components.
• Avoid Unnecessary Repairs: By accurately diagnosing the issue, we can help you avoid unnecessary repairs, saving you time and money.

Example Scenario

A BMW owner receives a quote of $800 to replace the fuel level sensors at a local repair shop. They contact AutoExplain.com, and we remotely diagnose the issue, confirm the fuel level sensors are faulty, and provide step-by-step instructions for replacing them. The owner purchases the sensors for $200 and performs the repair themselves, saving $600 in labor costs.

Don’t overspend on repairs. Contact AutoExplain.com via WhatsApp (+84)967469410 or Email [email protected] for cost-effective remote support and expert guidance.

FAQ: Decoding the 651b BMW Code

Here are some frequently asked questions about the 651b BMW code, covering common issues, diagnostic tips, and repair strategies. AutoExplain.com provides expert answers and remote support to help you resolve this fuel system issue efficiently.

1. What does the 651b code specifically mean on a BMW?

   The 651b code on a BMW typically indicates a problem with the fuel transfer system, particularly related to the suction jet pump (fuel transfer pump) or fuel level sensors in vehicles with saddle-shaped fuel tanks. It often means that fuel is not being properly transferred from one side of the tank to the other, leading to fuel starvation on the side where the fuel pump is located.

2. Can a faulty fuel cap cause the 651b code?

   While a faulty fuel cap is more likely to trigger evap-related codes, a severely leaking fuel cap can affect the fuel system’s pressure balance. It’s always a good idea to check the fuel cap as part of your initial inspection, but it’s less likely to be the primary cause of the 651b code.

3. How do I test the suction jet pump on my BMW?

   To test the suction jet pump, start by listening for its operation when the fuel level is low (less than half a tank). You should hear a whirring or buzzing sound. You can also use INPA to monitor fuel levels on both sides of the tank. If the fuel level on the passive side remains high while the active side is low, the suction jet pump is not working correctly.

4. What is the role of the fuel level sensors in triggering the 651b code?

   Fuel level sensors provide readings to the ECU about the amount of fuel in each side of the tank. If these sensors are faulty and provide inaccurate readings, the ECU may not properly manage fuel transfer, leading to fuel starvation and triggering the 651b code.

5. Is it possible to fix the 651b code without using INPA?

   While you can perform basic inspections and replace components without INPA, it is highly recommended for accurate diagnostics. INPA allows you to monitor fuel level sensors, fuel pump operation, and other critical parameters, helping you pinpoint the exact cause of the problem.

6. How often should I replace the fuel filter on my BMW to prevent fuel system issues?

   It is generally recommended to replace the fuel filter on your BMW every 30,000 miles or as specified in your vehicle’s maintenance schedule. A clogged fuel filter can restrict fuel flow, causing the fuel pump to work harder and potentially leading to fuel system issues.

7. Can low fuel pressure trigger the 651b code?

   Yes, low fuel pressure can be a contributing factor. If the fuel pump is weak or failing, it may not be able to maintain adequate fuel pressure, especially when the fuel level in the active side of the tank is low. This can lead to fuel starvation and trigger the 651b code.

8. What are the symptoms of a failing fuel pump in a BMW?

   Symptoms of a failing fuel pump in a BMW can include difficulty starting, rough idling, reduced performance, engine stalling (especially when the fuel level is low), and the illumination of the check engine light. You may also notice unusual noises from the fuel pump area.

9. Is it safe to drive my BMW with the 651b code?

   Driving with the 651b code is not recommended, as it indicates a problem with the fuel delivery system. This can lead to engine stalling, reduced performance, and potential damage to the fuel pump. It is best to diagnose and repair the issue as soon as possible.

10. How can AutoExplain.com help me fix the 651b code on my BMW?

    AutoExplain.com offers expert remote assistance to help you diagnose and repair the 651b code. Our services include remote diagnostics, step-by-step repair guidance, and expert advice from experienced BMW technicians. We can help you pinpoint the exact cause of the problem, provide detailed instructions for repair, and answer any questions you may have along the way.

Contact AutoExplain.com for Expert Support

Don’t let the 651b code keep you off the road. Contact AutoExplain.com via WhatsApp (+84)967469410 or Email AutoExplain[email protected] for fast, accurate, and reliable remote assistance. Our team of experienced BMW technicians is ready to help you diagnose and repair the issue, ensuring your BMW runs smoothly. Visit our office at 1500 N Grant ST Sten Denver, CO 80203.