What Causes BMW A559 Code and How to Fix It?

The BMW A559 code signifies a potential issue with the power supply or activation of certain control units, specifically the 15/30 F-G terminals, often pointing to a parasitic drain. Discover effective troubleshooting steps and reliable solutions, including professional remote support from AutoExplain, to resolve this frustrating electrical problem in your BMW and keep your car running smoothly. We’ll help you diagnose the root cause of the error code, whether it’s a faulty module, wiring issue, or software glitch.

1. What Does the BMW A559 Code Mean?

The BMW A559 code indicates a fault related to the power supply or activation of specific control units in your BMW. This code often means there is a problem with the terminal 15/30 F-G shutdown, suggesting a potential parasitic drain on the battery, which can lead to the “Excessive Battery Drain” warning.

1.1 Understanding Terminal 15/30 F-G

What are terminals 15 and 30 in a BMW and what role do F and G play?

Terminal 30 provides a direct, unfused connection to the battery. Terminal 15 is an ignition-switched power supply. F and G refer to specific circuits within the power distribution system. Problems with these circuits can cause the A559 code.

1.2 Common Symptoms Associated with the A559 Code

What are the symptoms of BMW A559 code?

Common symptoms associated with the A559 code include:

• “Excessive Battery Drain” warning message on the iDrive display.
• Comfort access not working.
• Battery draining quickly, especially overnight.
• Difficulty starting the car.
• Modules not shutting down properly.

1.3 Potential Causes of the A559 Code

What can cause BMW A559 code?

Several factors can trigger the A559 code, including:

• Faulty Control Modules: A defective module (like the KOMBI, CAS, JBE, or FRM) may not shut down properly, causing a continuous drain.
• Wiring Issues: Damaged or corroded wiring can create parasitic draws.
• Software Glitches: Software problems in a control module can prevent it from entering sleep mode.
• IBS Sensor Malfunction: Although less common, a faulty IBS (Intelligent Battery Sensor) can cause incorrect readings and lead to the code.
• Aftermarket Accessories: Improperly installed aftermarket electronics can draw excessive current.

2. How to Diagnose the BMW A559 Code

Diagnosing the A559 code requires a systematic approach to pinpoint the source of the battery drain. Start with basic checks and then move to more advanced diagnostic procedures.

2.1 Preliminary Checks

What are the preliminary checks for BMW A559 code?

Before diving into advanced diagnostics, perform these initial checks:

1. Battery Condition: Ensure the battery is in good condition and fully charged. A weak battery can trigger false codes.
2. Charging System: Verify the charging system is functioning correctly. Check the alternator output to ensure it’s within the specified range (typically 13.5-14.5V).
3. Visual Inspection: Inspect all wiring harnesses and connectors for signs of damage, corrosion, or loose connections. Pay close attention to the battery terminals and ground connections.

2.2 Using Diagnostic Tools

How to use diagnostic tools to check BMW A559 code?

Diagnostic tools like ISTA (Integrated Service Technical Application) or similar BMW-specific scanners are essential for diagnosing the A559 code.

1. Read Fault Codes: Connect the diagnostic tool and read all stored fault codes. Note all codes, as they may provide additional clues.
2. Monitor Module Status: Use the tool to monitor the status of various control modules (e.g., CAS, JBE, FRM) to see if they are entering sleep mode correctly after the car is turned off.
3. Perform Activation Tests: Activate and deactivate different components to see if any cause an unexpected current draw.

2.3 Parasitic Drain Testing

What is parasitic drain test?

A parasitic drain test measures the amount of current being drawn from the battery when the car is off. This test helps identify if there is an excessive drain and isolate the circuit causing the problem.

2.3.1 Procedure for Parasitic Drain Testing

How to perform parasitic drain test?

1. Preparation: Ensure all doors are closed, the ignition is off, and all accessories are turned off. Wait for at least 15-20 minutes to allow the car’s systems to enter sleep mode.
2. Connect Ammeter: Disconnect the negative battery cable and connect an ammeter in series between the cable and the negative battery terminal.
3. Monitor Current Draw: Observe the ammeter reading. A normal parasitic draw should be less than 50-80mA (0.05-0.08A).
4. Isolate the Drain: If the current draw is higher than specified, start pulling fuses one at a time, waiting a few seconds after each to see if the current drops. When the current drops, the circuit you just pulled is the one with the parasitic drain.
5. Further Diagnosis: Once you’ve identified the circuit, investigate the components and wiring within that circuit to pinpoint the exact cause of the drain.

2.4 Module-Specific Checks

If the parasitic drain test points to a specific circuit, further module-specific checks are necessary.

2.4.1 KOMBI Module

How to check KOMBI module?

The KOMBI module (instrument cluster) has been known to cause the A559 code. Check the KOMBI module by:

• Visual Inspection: Look for signs of damage or corrosion on the module and its connectors.
• Module Testing: Use ISTA to perform diagnostic tests on the KOMBI module and check for internal faults.
• Software Update: Ensure the KOMBI module has the latest software. Outdated software can sometimes cause issues.

2.4.2 CAS Module

How to check CAS module?

The CAS (Car Access System) module controls the ignition and starting functions. Check the CAS module by:

• Monitoring Status: Use ISTA to monitor the CAS module’s status and see if it is entering sleep mode correctly.
• Fault Code Check: Check for any CAS-specific fault codes that may indicate a problem.
• Wiring Inspection: Inspect the wiring and connectors associated with the CAS module for damage.

2.4.3 JBE Module

How to check JBE module?

The JBE (Junction Box Electronics) module is a central distribution point for electrical power. Check the JBE module by:

• Visual Inspection: Inspect the JBE module for any signs of water damage or corrosion.
• Fuse Check: Check all fuses associated with the JBE module to ensure they are intact.
• Module Testing: Use ISTA to perform diagnostic tests on the JBE module and check for internal faults.

2.4.4 FRM Module

How to check FRM module?

The FRM (Footwell Module) controls lighting and other functions. Check the FRM module by:

• Software Update: Ensure the FRM module has the latest software.
• Fault Code Check: Check for any FRM-specific fault codes.
• Wiring Inspection: Inspect the wiring and connectors associated with the FRM module.

2.5 IBS Sensor Check

How to check IBS sensor?

The IBS (Intelligent Battery Sensor) monitors battery condition. Although less common, a faulty IBS can contribute to the A559 code.

• Diagnostic Scan: Use a diagnostic tool to read the IBS sensor data. Check for any fault codes related to the IBS.
• Live Data: Monitor the IBS sensor’s live data, including voltage, current, and temperature readings, to see if they are within the expected range.
• Wiring Inspection: Inspect the wiring and connectors associated with the IBS sensor.

3. How to Fix the BMW A559 Code

Once you’ve diagnosed the cause of the A559 code, you can begin implementing the necessary repairs.

3.1 Repairing Wiring Issues

How to repair wiring issues?

If damaged or corroded wiring is the cause, repair or replace the affected wires.

1. Identify the Damaged Wire: Locate the specific wire causing the issue.
2. Repair or Replace: Depending on the extent of the damage, either repair the wire by splicing in a new section or replace the entire wire.
3. Proper Connections: Ensure all connections are secure and properly insulated to prevent future issues.

3.2 Replacing Faulty Modules

How to replace faulty modules?

If a faulty module is identified, replacement is often the best solution.

1. Disconnect Battery: Disconnect the negative battery cable before replacing any module.
2. Remove Old Module: Carefully remove the old module, disconnecting all wiring harnesses.
3. Install New Module: Install the new module, ensuring all connections are secure.
4. Coding/Programming: Some modules require coding or programming to be properly integrated into the car’s system. Use ISTA or a similar tool to perform the necessary coding.

3.3 Software Updates

How to do software updates?

Outdated software can cause various issues, including the A559 code.

1. Use ISTA: Use ISTA or another BMW-compatible tool to check for available software updates for the affected modules.
2. Follow Instructions: Follow the on-screen instructions to perform the software update. Ensure the battery is fully charged and stable during the update process.
3. Verification: After the update, clear any fault codes and verify that the A559 code is resolved.

3.4 Addressing Aftermarket Accessories

How to address aftermarket accessories?

Improperly installed aftermarket accessories can cause parasitic drains.

1. Inspect Installation: Check the installation of any aftermarket accessories, such as stereos, alarms, or lighting.
2. Disconnect Accessories: Disconnect the accessories one at a time to see if the parasitic drain disappears.
3. Proper Installation: If an accessory is causing the drain, ensure it is properly installed with the correct wiring and connections.

4. Preventing Future Occurrences of the A559 Code

How to prevent future occurrences of BMW A559 code?

To prevent the A559 code from recurring, consider the following:

• Regular Battery Maintenance: Keep the battery in good condition with regular charging and maintenance.
• Professional Installations: Have aftermarket accessories installed by qualified professionals.
• Regular Diagnostics: Perform regular diagnostic scans to identify and address potential issues early.
• Software Updates: Keep the car’s software up to date.

5. Common Mistakes to Avoid

What are the common mistakes to avoid with BMW A559 code?

• Ignoring Preliminary Checks: Don’t skip basic checks like battery condition and visual inspections.
• Incorrect Diagnosis: Ensure you accurately diagnose the cause of the code before performing any repairs.
• Neglecting Software Updates: Keep the car’s software up to date.
• Improper Installations: Avoid installing aftermarket accessories yourself unless you have the necessary expertise.

6. How AutoExplain Can Help

Experiencing the A559 code on your BMW can be frustrating, but you don’t have to tackle it alone. AutoExplain offers comprehensive remote support services to help you diagnose and resolve complex electrical issues quickly and efficiently.

6.1 Remote Diagnostic Support

How can AutoExplain help with remote diagnostic support?

AutoExplain’s team of experienced technicians can remotely connect to your BMW’s diagnostic system to read fault codes, monitor module status, and perform activation tests. This remote diagnostic support can help pinpoint the exact cause of the A559 code without the need for a physical visit to a mechanic.

6.2 Step-by-Step Guidance

How can AutoExplain provide step-by-step guidance?

Our experts provide step-by-step guidance on performing parasitic drain tests, module-specific checks, and other diagnostic procedures. We’ll walk you through each step, ensuring you understand the process and can accurately identify the source of the problem.

6.3 Software Solutions and Coding Assistance

How can AutoExplain help with software solutions and coding assistance?

Many electrical issues require software updates or coding to resolve. AutoExplain can remotely perform software updates for various modules and provide coding assistance to ensure your BMW’s systems are properly integrated and functioning correctly.

6.4 Expert Advice and Troubleshooting

How can AutoExplain provide expert advice and troubleshooting?

With years of experience working on BMW electrical systems, our technicians can offer expert advice and troubleshooting tips to help you resolve the A559 code and prevent it from recurring. We’ll share our knowledge and insights to ensure you have the information you need to keep your BMW running smoothly.

6.5 Benefits of Remote Support

What are the benefits of remote support from AutoExplain?

• Convenience: Get expert support from the comfort of your own garage.
• Speed: Resolve issues quickly without waiting for an appointment.
• Cost-Effective: Save money on expensive mechanic visits.
• Expertise: Access specialized knowledge and experience.

7. Case Studies: Real-World Examples

Looking at real-world examples can provide a clearer understanding of how the A559 code manifests and how to effectively address it.

7.1 Case Study 1: Faulty KOMBI Module

Problem: A BMW owner experienced the “Excessive Battery Drain” warning and the A559 code. Initial checks revealed a higher-than-normal parasitic draw.

Diagnosis: Using ISTA, AutoExplain technicians remotely monitored the status of various modules and identified that the KOMBI module was not entering sleep mode.

Solution: The KOMBI module was replaced and coded. The parasitic draw returned to normal, and the A559 code was resolved.

7.2 Case Study 2: Wiring Issue in the JBE Circuit

Problem: A BMW technician was called to fix a BMW with a recurring A559 code. Parasitic drain testing isolated the issue to the JBE circuit.

Diagnosis: A visual inspection revealed corroded wiring in the JBE circuit due to water intrusion.

Solution: The corroded wiring was repaired, and the connections were properly sealed. The A559 code was resolved.

7.3 Case Study 3: Aftermarket Alarm System

Problem: A BMW owner installed an aftermarket alarm system and began experiencing the A559 code and a rapidly draining battery.

Diagnosis: AutoExplain technicians advised disconnecting the alarm system. The parasitic drain disappeared.

Solution: The alarm system was reinstalled by a professional with the correct wiring and connections. The A559 code was resolved.

8. FAQ: Addressing Common Questions About the A559 Code

8.1 Can a faulty battery cause the A559 code?

Yes, a faulty or weak battery can trigger the A559 code.

8.2 How long does it take for a BMW to enter sleep mode?

A BMW typically takes 15-20 minutes to enter sleep mode after the ignition is turned off.

8.3 What is the normal parasitic draw for a BMW?

A normal parasitic draw should be less than 50-80mA (0.05-0.08A).

8.4 Can I use a generic OBD2 scanner to diagnose the A559 code?

While a generic OBD2 scanner can read some codes, it may not provide the detailed information needed to diagnose the A559 code effectively. BMW-specific tools like ISTA are recommended.

8.5 Do I need to code a new battery in a BMW?

Yes, you need to code a new battery in a BMW to ensure the car’s systems properly manage the battery’s charging and discharging.

8.6 Can software updates fix the A559 code?

Yes, software updates can sometimes fix the A559 code, especially if the issue is related to a software glitch in a control module.

8.7 What modules are most commonly associated with the A559 code?

The modules most commonly associated with the A559 code include the KOMBI, CAS, JBE, and FRM.

8.8 How do I check for water damage in the JBE module?

Inspect the JBE module for any signs of corrosion, water stains, or dampness.

8.9 Can a faulty IBS sensor cause the A559 code?

Yes, a faulty IBS (Intelligent Battery Sensor) can cause incorrect readings and lead to the A559 code.

8.10 What should I do if I suspect a parasitic drain?

Perform a parasitic drain test using an ammeter to measure the current draw from the battery when the car is off.

9. Conclusion: Resolve Your BMW A559 Code with AutoExplain

The BMW A559 code can be a challenging issue to diagnose and resolve, but with the right approach and tools, you can identify the root cause and implement the necessary repairs. Remember to start with basic checks, use diagnostic tools effectively, and consider the potential causes discussed in this guide. For expert assistance and reliable solutions, AutoExplain is here to help. Contact us today to get the support you need to keep your BMW running smoothly.

Don’t let electrical issues keep you off the road. Contact AutoExplain today for expert remote support and get your BMW back in top condition. Reach out via WhatsApp at (+84)967469410, email us at [email protected], or visit our website at AutoExplain.com. Our office is located at 1500 N Grant ST Sten Denver, CO 80203. Let us help you diagnose and fix your car problems quickly and efficiently.