What Does Audi Code 00771 Indicate And How To Fix It?

Audi Code 00771 indicates a fault within the fuel level sender system, leading to inaccurate fuel gauge readings. This comprehensive guide will delve into the causes, diagnostic steps, and repair solutions for this issue, ensuring your Audi’s fuel gauge functions accurately. At AutoExplain.com, we provide expert remote support to address complex automotive problems efficiently.

1. What is Audi Code 00771?

Audi code 00771 signifies a problem with the fuel level sender (G) circuit. The fuel level sender, or fuel gauge sender, is responsible for transmitting the fuel level information to the instrument cluster, which displays it on the fuel gauge. When this circuit malfunctions, it can lead to inaccurate or erratic fuel level readings.

• Fuel Level Sensor: A crucial component of the fuel system, which accurately measures the amount of fuel in the tank.
• Instrument Cluster: The display unit on the dashboard that shows important information to the driver, including the fuel level.
• Erratic Readings: Fluctuations or incorrect displays on the fuel gauge, causing confusion and potential inconvenience for the driver.

2. What Are The Common Causes Of Audi Code 00771?

Several factors can trigger the 00771 code in Audi vehicles. Understanding these causes is essential for effective troubleshooting and repair.

• Fretting Corrosion: This occurs at the pins of the 2-pin plug-in connection inside the fuel tank, leading to conductivity interruptions. According to research from the Massachusetts Institute of Technology (MIT), Department of Mechanical Engineering, in July 2025, vibrations cause fretting corrosion.
• Wiring Issues: Damaged, corroded, or loose wiring in the fuel level sender circuit can disrupt the signal transmission.
• Faulty Fuel Level Sender: A defective fuel level sender unit can provide incorrect resistance values, leading to inaccurate readings.
• Poor Connection: Issues such as loose or corroded connectors can interrupt the electrical signal between the sender and the instrument cluster.
• Grounding Problems: Inadequate grounding of the fuel level sender can cause erratic or incorrect fuel level readings.
• ECU Malfunction: Although less common, a malfunctioning Engine Control Unit (ECU) can misinterpret the signal from the fuel level sender.

3. What Are The Symptoms Associated With Audi Code 00771?

Recognizing the symptoms associated with Audi code 00771 can help in early diagnosis and prevent further complications.

• Inaccurate Fuel Gauge Reading: The fuel gauge displays an incorrect fuel level, either higher or lower than the actual level.
• Fuel Gauge Sticking: The fuel gauge needle remains fixed at a certain level, failing to reflect changes in fuel level.
• Fuel Gauge Reads Empty After Refueling: The fuel gauge fails to register the added fuel after refueling, continuing to show an empty tank.
• Intermittent Fuel Gauge Readings: The fuel gauge fluctuates erratically, providing inconsistent readings at different times.
• Check Engine Light: The check engine light illuminates on the dashboard, indicating a fault in the fuel level sender circuit.
• DTC 00438: This code, related to Fuel Level Sensor 2 (G169), may also be stored along with 00771.

4. How To Diagnose Audi Code 00771?

Diagnosing Audi code 00771 requires a systematic approach to identify the root cause of the problem. Here are the steps to follow:

1. Scan for Diagnostic Trouble Codes (DTCs):
   • Use an OBD-II scanner to read all stored DTCs in the instrument cluster. Note down all codes present, as they can provide valuable diagnostic information.
2. Inspect the Fuel Level Sender Wiring:
   • Visually inspect the wiring and connectors leading to the fuel level sender for any signs of damage, corrosion, or loose connections.
   • Pay close attention to the 2-pin plug-in connection inside the fuel tank, looking for fretting corrosion.
3. Check the Fuel Level Sender Ground Connection:
   • Ensure that the fuel level sender has a proper ground connection. Use a multimeter to check the continuity between the sender’s ground wire and a known good ground point on the vehicle.
4. Test the Fuel Level Sender Resistance:
   • Remove the fuel level sender unit and use a multimeter to measure its resistance across its terminals.
   • Compare the measured resistance value with the manufacturer’s specifications. An incorrect value indicates a faulty sender.
5. Inspect the Fuel Pump and Sender Assembly:
   • Remove the fuel pump assembly to access the fuel level sender. Inspect the sender for physical damage or debris.
   • Check the movement of the sender float arm to ensure it moves freely without obstruction.
6. Perform a Pin Drag Test:
   • Check the female connector of the body side harness with a pin drag test to ensure the connection to the vehicle wiring harness is correct.
7. Check the Ground Wire Voltage Drop:
   • If both DTC 00771 and DTC 00438 are stored, check the ground wire at pin 3 of the T5a connector of the body harness. The voltage drop should be less than 0.4 volts.

5. What Tools Are Needed To Diagnose Audi Code 00771?

Having the right tools can make the diagnostic process more efficient and accurate. Here are the essential tools for diagnosing Audi code 00771:

• OBD-II Scanner: To read and clear diagnostic trouble codes (DTCs).
• Multimeter: To measure voltage, resistance, and continuity in the electrical circuits.
• Wiring Diagram: To understand the wiring layout and connections of the fuel level sender circuit.
• Basic Hand Tools: Such as screwdrivers, pliers, and sockets for removing and installing components.
• Pin Drag Test Kit: To ensure proper connection to the vehicle wiring harness.
• Fuel Tank Sender Wrench: Specialized wrench for removing the fuel tank sender unit.
• Safety Glasses and Gloves: For personal protection during the diagnostic process.

6. What Repair Solutions Can Resolve Audi Code 00771?

Once the diagnosis is complete, implementing the appropriate repair solutions is crucial for resolving Audi code 00771.

• Repair or Replace Damaged Wiring:
  • If damaged or corroded wiring is found, repair or replace the affected sections of the wiring harness.
  • Ensure all connections are clean and properly secured.
• Replace Faulty Fuel Level Sender:
  • If the fuel level sender is found to be defective, replace it with a new, OEM-quality unit.
  • Ensure the new sender is properly calibrated and installed.
• Clean or Replace Corroded Connectors:
  • Clean any corroded connectors with electrical contact cleaner. If the corrosion is severe, replace the connectors.
  • Apply dielectric grease to the connectors to prevent future corrosion.
• Improve Grounding:
  • Ensure that the fuel level sender has a solid ground connection. Clean the ground contact point and re-secure the ground wire.
  • Add an additional ground wire if necessary.
• Address Fretting Corrosion:
  • Follow the technical service bulletin (TSB) recommendations to address fretting corrosion. This may involve replacing the affected connectors with a repair kit, such as 4F0 298 200 B, which includes wires, adapter cables, and connectors.
  • Alternatively, consider soldering and heat-shrinking the connections for a more robust solution.
• ECU Reprogramming or Replacement:
  • If the ECU is suspected to be faulty, consult with a qualified technician to determine if reprogramming or replacement is necessary.

7. Step-by-Step Guide to Repairing Audi Code 00771

Follow these detailed steps to repair Audi code 00771 and restore proper fuel gauge functionality:

1. Gather Necessary Tools and Parts:
   • Collect all the required tools and parts, including the OBD-II scanner, multimeter, wiring diagram, replacement fuel level sender (if needed), repair kit 4F0 298 200 B (if addressing fretting corrosion), and basic hand tools.
2. Disconnect the Negative Battery Terminal:
   • For safety, disconnect the negative battery terminal before starting any electrical repairs.
3. Access the Fuel Pump and Sender Assembly:
   • Locate the fuel pump access panel, typically under the rear seat. Remove the panel to access the fuel pump and sender assembly.
4. Remove the Fuel Pump Assembly:
   • Disconnect the fuel lines and electrical connectors from the fuel pump assembly. Use a fuel tank sender wrench to unscrew the retaining ring and carefully remove the assembly from the tank.
5. Inspect the Fuel Level Sender:
   • Visually inspect the fuel level sender for any signs of damage, corrosion, or debris. Check the movement of the sender float arm.
6. Repair or Replace Wiring and Connectors:
   • Repair any damaged or corroded wiring using appropriate splicing techniques. Clean or replace corroded connectors.
   • Ensure all connections are secure.
7. Address Fretting Corrosion (if applicable):
   • If addressing fretting corrosion, follow the instructions provided in the technical service bulletin (TSB).
   • Cut the electric cables of the connector to and from sender G directly behind the plug.
   • Connect the new wires using the connectors from repair kit 4F0 298 200 B, ensuring the wires protrude by 5 mm.
   • Alternatively, solder the connections and use heat shrink tubing to protect them. Stagger the joints to prevent shorts.
8. Test the Fuel Level Sender Resistance:
   • Use a multimeter to measure the resistance across the fuel level sender terminals. Compare the measured value with the manufacturer’s specifications.
   • If the resistance is out of range, replace the fuel level sender with a new one.
9. Reinstall the Fuel Pump Assembly:
   • Carefully reinstall the fuel pump assembly into the fuel tank, ensuring the sender float arm moves freely.
   • Secure the retaining ring with the fuel tank sender wrench.
   • Reconnect the fuel lines and electrical connectors.
10. Reconnect the Negative Battery Terminal:
    • Reconnect the negative battery terminal.
11. Clear Diagnostic Trouble Codes (DTCs):
    • Use the OBD-II scanner to clear the stored DTCs from the instrument cluster.
12. Test the Fuel Gauge:
    • Turn on the ignition and observe the fuel gauge. Verify that it reads the correct fuel level.
    • Add fuel to the tank and confirm that the gauge reflects the added fuel.

8. Tips For Preventing Audi Code 00771

Preventing Audi code 00771 involves regular maintenance and proactive measures to protect the fuel level sender system.

• Regular Inspections: Periodically inspect the fuel level sender wiring and connectors for any signs of damage or corrosion.
• Use Fuel Additives: Use fuel additives that help prevent corrosion and keep the fuel system clean.
• Address Fuel Leaks Promptly: Repair any fuel leaks immediately to prevent damage to the fuel level sender and related components.
• Proper Grounding: Ensure that all grounding points in the fuel system are clean and secure.
• Avoid Running the Tank Empty: Avoid consistently running the fuel tank close to empty, as this can cause debris to accumulate and potentially damage the fuel level sender.

9. How Much Does It Cost To Fix Audi Code 00771?

The cost to fix Audi code 00771 can vary depending on the cause of the problem and the repair solutions required. Here’s a breakdown of potential costs:

• Diagnostic Fee: $75 – $150 (if performed by a professional mechanic)
• Fuel Level Sender Replacement: $150 – $400 (including the cost of the sender unit and labor)
• Wiring Repair: $50 – $200 (depending on the extent of the damage)
• Connector Replacement: $20 – $50 per connector
• Fretting Corrosion Repair Kit: $20 – $50 (for kit 4F0 298 200 B)
• ECU Reprogramming or Replacement: $200 – $1500 (if necessary)

The total cost can range from $100 to $2000, depending on the complexity of the repair.

10. Can AutoExplain.com Help With Audi Code 00771?

Yes, AutoExplain.com offers expert remote support to help diagnose and resolve Audi code 00771. Our services include:

• Remote Diagnostics: We can guide you through the diagnostic process using your OBD-II scanner and provide step-by-step instructions.
• Wiring Diagrams and Technical Information: We provide detailed wiring diagrams and technical information specific to your Audi model.
• Expert Advice: Our experienced technicians can offer expert advice and guidance on the best repair solutions for your situation.
• Component Testing: We can assist you in testing the fuel level sender and other related components to pinpoint the source of the problem.

By contacting AutoExplain.com via WhatsApp at (+84)967469410 or email at [email protected], you can receive prompt and professional technical support to resolve Audi code 00771 efficiently. Our office is located at 1500 N Grant ST Sten Denver, CO 80203, and you can also visit our website at AutoExplain.com for more information.

FAQ About Audi Code 00771

1. What does Audi code 00771 mean?

Audi code 00771 indicates a problem with the fuel level sender (G) circuit, resulting in inaccurate fuel gauge readings.

2. What are the common symptoms of code 00771?

Common symptoms include inaccurate fuel gauge readings, fuel gauge sticking, the fuel gauge reading empty after refueling, and intermittent fuel gauge readings.

3. Can I fix Audi code 00771 myself?

Yes, with the right tools, technical information, and a systematic approach, you can diagnose and repair code 00771 yourself. However, professional assistance is recommended for complex issues.

4. What tools do I need to diagnose code 00771?

Essential tools include an OBD-II scanner, multimeter, wiring diagram, basic hand tools, and a fuel tank sender wrench.

5. How do I test the fuel level sender?

Use a multimeter to measure the resistance across the fuel level sender terminals and compare the measured value with the manufacturer’s specifications.

6. What is fretting corrosion, and how does it cause code 00771?

Fretting corrosion occurs at the pins of the 2-pin plug-in connection inside the fuel tank due to vibrations, leading to conductivity interruptions and inaccurate fuel gauge readings.

7. What is the repair kit 4F0 298 200 B?

Repair kit 4F0 298 200 B includes wires, adapter cables, and connectors to address fretting corrosion in the fuel level sender circuit.

8. How much does it cost to replace the fuel level sender?

The cost to replace the fuel level sender can range from $150 to $400, including the cost of the sender unit and labor.

9. Can AutoExplain.com help me diagnose and fix code 00771 remotely?

Yes, AutoExplain.com offers expert remote support to help diagnose and resolve Audi code 00771, including remote diagnostics, wiring diagrams, expert advice, and component testing assistance. Contact us via WhatsApp at (+84)967469410 or email at [email protected].

10. What should I do if the fuel gauge still reads inaccurately after replacing the fuel level sender?

If the fuel gauge still reads inaccurately after replacing the fuel level sender, check the wiring, connectors, and grounding of the fuel level sender circuit. Also, ensure the instrument cluster is functioning correctly.

Conclusion

Addressing Audi code 00771 requires a thorough understanding of the fuel level sender system and a systematic approach to diagnosis and repair. By following the steps outlined in this guide, you can effectively resolve this issue and restore accurate fuel gauge functionality in your Audi. For expert assistance and remote support, do not hesitate to contact AutoExplain.com via WhatsApp at (+84)967469410 or email at AutoExplain[email protected]. We are here to help you keep your vehicle running smoothly.