What Causes Audi Fault Code 00979 And How To Fix It?

Audi fault code 00979 indicates a malfunction within the control circuit for the headlight leveling system. AutoExplain.com provides in-depth diagnostics and remote programming to help technicians resolve this issue efficiently. Contact us today to get expert technical support and resolve car errors quickly.

1. What Does Audi Fault Code 00979 Mean?

Audi fault code 00979 means there’s a problem with the headlight range control module’s power supply (J431). This issue prevents the headlights from automatically adjusting their vertical angle, impacting visibility and potentially causing glare for other drivers. This fault usually means a problem with the power supply for the headlight range control module.

• Headlight Range Control: Modern vehicles often include systems that automatically adjust the headlight beam’s vertical angle based on vehicle load and driving conditions. This ensures optimal visibility without blinding oncoming traffic.

• Module Malfunction: The “control circuit malfunction” aspect suggests the fault might not be a simple power supply issue but could involve the internal electronics of the J431 module.

• Impact: If the headlight leveling system is malfunctioning, the headlights might point too low, reducing visibility, or too high, causing glare for other drivers.

2. What Are The Common Symptoms Of Audi Fault Code 00979?

The common symptoms of Audi fault code 00979 include headlights not leveling properly, an error message on the dashboard, and potentially a failed vehicle inspection. Here are the notable symptoms:

• Headlights Don’t Self-Adjust: The most obvious symptom is that the headlights don’t automatically adjust their angle when you start the car or when the vehicle’s load changes (e.g., passengers in the back, a loaded trunk).

• Warning Light/Message: Many Audi models will display a warning light or message on the instrument cluster indicating a problem with the headlight leveling system. The specific wording will vary by model and year.

• Poor Nighttime Visibility: If the headlights are stuck pointing too low, you’ll experience reduced visibility at night, especially on uneven roads or when carrying loads.

• Headlight Glare: Conversely, if the headlights are stuck pointing too high, they can cause excessive glare for oncoming drivers, which is dangerous and illegal.

• Failed Inspection: In many regions, a properly functioning headlight leveling system is required to pass a vehicle safety inspection. A 00979 fault code will likely cause the vehicle to fail the inspection.

3. What Are The Potential Causes Of Audi Fault Code 00979?

Potential causes of Audi fault code 00979 range from simple wiring problems to a faulty control module. Some of the reasons are:

• Wiring Issues: Damaged, corroded, or loose wiring connecting the headlight range control module (J431) to the power source, ground, or other components is a common cause.

• Faulty Module: The J431 module itself could be defective. Internal electronic components can fail over time due to heat, vibration, or electrical surges.

• Blown Fuse: A blown fuse in the circuit that powers the J431 module can obviously cause a loss of power.

• Grounding Problems: A poor or missing ground connection for the J431 module can disrupt its operation and trigger the fault code.

• Sensor Issues: The headlight leveling system relies on sensors (often located on the suspension) to detect vehicle orientation. If these sensors are faulty or sending incorrect data, it can affect the J431 module’s function.

• Software Glitches: In rare cases, a software glitch in the J431 module or the vehicle’s central control unit could cause the 00979 fault code.

4. How To Diagnose Audi Fault Code 00979?

Diagnosing Audi fault code 00979 requires a systematic approach, starting with basic checks and progressing to more advanced troubleshooting steps. The steps are:

1. Scan for Fault Codes: Use a diagnostic scan tool (like VCDS, ODIS, or a generic OBD-II scanner) to confirm the presence of the 00979 fault code and check for any other related codes.

2. Visual Inspection: Carefully inspect all wiring and connectors associated with the headlight range control module (J431). Look for signs of damage, corrosion, or loose connections. Pay close attention to the module’s power and ground wires.

3. Check Fuses: Locate the fuse that protects the J431 module and check if it’s blown. Replace the fuse with a new one of the correct amperage if necessary.

4. Test Power and Ground: Use a multimeter to verify that the J431 module is receiving the correct voltage and has a good ground connection. Check the wiring diagrams for your specific Audi model to identify the correct pins to test.

5. Sensor Check: If possible, use the scan tool to read the values from the ride height sensors. Ensure that the sensors are providing reasonable data and that the values change when the vehicle’s suspension is compressed or extended.

6. Module Isolation: If the power, ground, wiring, and sensors all check out, the J431 module itself is likely faulty. Disconnect the module and inspect the connector pins for corrosion or damage.

7. Wiring Continuity Test: Perform a continuity test on the wiring between the J431 module and the relevant sensors, power source, and ground points to rule out any hidden breaks or shorts in the wiring.

8. Software Check: Using a diagnostic tool, check if there are any available software updates for the J431 module or the vehicle’s central control unit. Updating the software might resolve intermittent glitches.

5. What Tools Are Needed To Fix Audi Fault Code 00979?

To fix Audi fault code 00979, you will need a variety of tools, ranging from basic hand tools to specialized diagnostic equipment. These include:

• Diagnostic Scan Tool: A diagnostic scan tool is essential for reading and clearing fault codes, as well as accessing live data from the vehicle’s control modules. VCDS (VAG-COM Diagnostic System) is a popular choice for Audi vehicles, but other professional-grade scan tools like Autel, Launch, or Snap-on can also be used.

• Multimeter: A multimeter is needed for testing voltage, continuity, and resistance in the electrical circuits related to the headlight leveling system.

• Wiring Diagram: A wiring diagram specific to your Audi model and year is crucial for identifying the correct wires and components to test. These diagrams can be found in the vehicle’s repair manual or online databases.

• Basic Hand Tools: You’ll need a set of basic hand tools, including screwdrivers, pliers, wire strippers, and socket wrenches, to access and work on the wiring and components.

• Wire Repair Kit: A wire repair kit with connectors, terminals, and crimping tools is useful for repairing damaged or corroded wiring.

• Fuse Tester: A fuse tester or test light can quickly check the condition of fuses without removing them.

• Headlight Adjustment Tool: After repairing the headlight leveling system, you might need a headlight adjustment tool to properly aim the headlights.

• OBD-II Extension Cable: An OBD-II extension cable can be helpful for accessing the diagnostic port in tight spaces.

• Laptop: If you’re using VCDS or other PC-based diagnostic software, you’ll need a laptop with the appropriate software installed.

• Flashlight or Work Light: Good lighting is essential for inspecting wiring and components in dimly lit areas.

6. What Are The Steps To Fix Audi Fault Code 00979?

Fixing Audi fault code 00979 involves addressing the underlying cause, which can range from simple repairs to more complex procedures. Here’s how you can address the code:

1. Address Wiring Issues: Repair any damaged, corroded, or loose wiring and connectors associated with the headlight range control module (J431). Clean corroded terminals with a wire brush or contact cleaner. Secure loose connections with new connectors or by crimping the existing ones.

2. Replace Blown Fuse: If you found a blown fuse during the diagnostic process, replace it with a new fuse of the correct amperage. Make sure to identify and address the cause of the blown fuse to prevent it from happening again.

3. Correct Grounding Problems: Ensure that the J431 module has a solid ground connection. Clean any corroded ground points and tighten the ground bolt or screw. If necessary, add a new ground wire to improve the connection.

4. Replace Faulty Module: If the J431 module itself is determined to be faulty, replace it with a new or refurbished module. You might need to program the new module to the vehicle using a diagnostic scan tool. AutoExplain.com provides remote programming services to assist with this step.

5. Repair or Replace Sensors: If the ride height sensors are faulty, repair or replace them as needed. Ensure that the new sensors are properly calibrated and aligned.

6. Update Software: If there are software updates available for the J431 module or the vehicle’s central control unit, perform the updates using a diagnostic scan tool. Follow the manufacturer’s instructions carefully during the update process.

7. Clear Fault Codes: After completing the repairs, clear the 00979 fault code using a diagnostic scan tool. Then, test the headlight leveling system to ensure that it’s functioning properly.

8. Verify Repair: After clearing the fault codes and testing the system, take the vehicle for a test drive to ensure that the headlight leveling system is working correctly under various driving conditions.

7. How Much Does It Cost To Fix Audi Fault Code 00979?

The cost to fix Audi fault code 00979 can vary widely depending on the underlying cause of the problem. Here’s a general breakdown:

• Simple Fixes: If the issue is a blown fuse, a corroded connector, or a loose wire, the repair cost could be as low as $20 to $50 for parts and a small amount of labor.

• Sensor Replacement: If a ride height sensor needs to be replaced, the cost could range from $100 to $300 per sensor, plus labor for installation and calibration.

• Module Replacement: Replacing the headlight range control module (J431) can be more expensive, with the module itself costing anywhere from $200 to $800, depending on the source (new, refurbished, or aftermarket). Labor for module replacement and programming can add another $100 to $300.

• Wiring Repair: If the wiring harness is severely damaged and needs to be repaired or replaced, the cost can range from $200 to $500, depending on the complexity of the repair.

• Diagnostic Fees: Most shops will charge a diagnostic fee to identify the cause of the fault code. This fee can range from $50 to $150, but it’s often waived if you proceed with the repair at the same shop.

8. Can I Fix Audi Fault Code 00979 Myself?

Whether you can fix Audi fault code 00979 yourself depends on your mechanical skills, diagnostic abilities, and access to tools.

• When DIY is Possible: If the problem turns out to be a simple issue like a blown fuse, a loose connector, or a corroded wire, you might be able to fix it yourself with basic hand tools and a multimeter.

• When Professional Help is Recommended: If the problem is more complex, such as a faulty headlight range control module, a defective ride height sensor, or damaged wiring harness, it’s best to seek professional help. These repairs often require specialized tools, diagnostic equipment, and programming skills.

• Safety Considerations: Working on electrical systems can be dangerous if you’re not familiar with automotive electrical systems. Disconnecting the battery and following proper safety precautions is essential.

• Potential Complications: Incorrectly diagnosing or repairing the problem can lead to further damage to the vehicle’s electrical system or other components.

9. How Can AutoExplain.com Help Me With Audi Fault Code 00979?

AutoExplain.com offers expert remote support to help technicians diagnose and resolve Audi fault code 00979 efficiently. We provide:

• Remote Diagnostics: Our experienced technicians can remotely access your vehicle’s diagnostic system using a compatible scan tool and internet connection. We can help you pinpoint the exact cause of the 00979 fault code and provide step-by-step troubleshooting guidance.

• Programming and Coding: If the repair requires programming or coding a new headlight range control module or other components, we can perform these tasks remotely. This eliminates the need to visit a dealership or specialized shop.

• Wiring Diagrams and Technical Information: We can provide you with access to detailed wiring diagrams, technical service bulletins, and other resources to help you understand the headlight leveling system and perform the necessary repairs.

• Expert Advice: Our team of automotive experts is available to answer your questions and provide guidance throughout the repair process. We can help you navigate complex diagnostic procedures and make informed decisions about the best course of action.

• Cost Savings: By using our remote support services, you can often save money on diagnostic fees, labor costs, and the expense of towing your vehicle to a shop.

Contact AutoExplain.com via WhatsApp at (+84)967469410 or email at [email protected] for expert technical assistance and get your Audi back on the road quickly. Our office is located at 1500 N Grant ST Sten Denver, CO 80203.

10. What Are Other Common Audi Fault Codes Related To Lighting?

Several other common Audi fault codes relate to the lighting system. Addressing these can help ensure optimal visibility and safety. Here are some:

FAQ About Audi Fault Code 00979

1. Can I drive my Audi with fault code 00979?

Yes, you can drive your Audi with fault code 00979, but it’s not recommended due to reduced headlight leveling functionality, which can impair visibility and pose safety risks, especially at night. Addressing the issue promptly is advisable.

2. How often does the Audi fault code 00979 occur?

The occurrence of Audi fault code 00979 varies, with higher incidence in older vehicles or those exposed to harsh conditions due to wiring degradation or component failure. Regular maintenance can help prevent this.

3. Can a dead battery cause Audi fault code 00979?

Yes, a dead or weak battery can sometimes cause Audi fault code 00979 because low voltage can affect the operation of the headlight range control module, leading to the fault code. Ensure your battery is in good condition.

4. Is it necessary to replace the headlight assembly to fix the 00979 code?

No, it is not always necessary to replace the entire headlight assembly to fix the 00979 code. The issue may stem from wiring, sensors, or the control module, which can be addressed separately. A thorough diagnosis is essential.

5. What is the function of the headlight range control module (J431)?

The headlight range control module (J431) automatically adjusts the vertical angle of the headlights based on vehicle load and driving conditions. This ensures optimal visibility without blinding oncoming traffic, enhancing safety.

6. Can I use a generic OBD-II scanner to read Audi fault code 00979?

Yes, you can use a generic OBD-II scanner to read Audi fault code 00979. However, for more detailed diagnostics and troubleshooting, a specialized scan tool like VCDS or ODIS is recommended, as it can provide access to Audi-specific fault codes and data.

7. How do ride height sensors affect the headlight leveling system?

Ride height sensors measure the distance between the vehicle’s body and the road, providing data to the headlight range control module. This data is used to adjust the headlight angle, ensuring proper illumination regardless of vehicle load or road conditions, thus maintaining safety.

8. Are there any software updates that can fix Audi fault code 00979?

Yes, in some cases, software updates can fix Audi fault code 00979. A software glitch in the headlight range control module or the vehicle’s central control unit can cause the fault code. Updating the software to the latest version may resolve the issue.

9. What maintenance steps can prevent Audi fault code 00979?

To prevent Audi fault code 00979, regularly inspect and maintain the headlight leveling system, check wiring for damage, ensure secure connections, keep sensors clean, and monitor battery health. Promptly address any issues to avoid system malfunctions.

10. How do I contact AutoExplain.com for remote support to fix Audi fault code 00979?

To contact AutoExplain.com for remote support to fix Audi fault code 00979, you can reach us via WhatsApp at (+84)967469410 or email at AutoExplain[email protected]. Our office is located at 1500 N Grant ST Sten Denver, CO 80203. We provide expert technical assistance to get your Audi back on the road quickly.