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Harley Code U0156: Causes and Fixes

by

Chase Manhattan

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Owner and Editor at The Wrench Network

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Hey y’all, it’s Chase Manhattan! I’m a life-long automotive and motorcycle enthusiast with a knack for diagnostics that I hope to share with you! Lately, I’ve been running my own motorcycle rental business, which you can read about here, and it has been a great experience that has allowed me to own numerous bikes that I probably couldn’t justify otherwise. Plus, it’s been a great way to experience new places while on vacation. If you haven’t heard of them before, I definitely recommend checking out the Riders-Share platform if you get the itch to ride while away from home, or if you want to explore a cheaper way to own and ride motorcycles!

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If you own a Harley-Davidson motorcycle, you may have encountered the U0156 diagnostic trouble code (DTC) at some point. This code refers to a lost communication error between the information center module and other modules in the bike’s electrical system. When this error occurs, it can cause issues with the speedometer, tachometer, and other gauges on your dashboard.

There are several possible causes for the U0156 code, including a loss of power or ground to the information center module, damaged wiring harnesses or connectors, or a faulty module itself. It is important to address this issue as soon as possible, as continued operation of the bike may cause further damage to the electrical system. In some cases, the bike may even need to be taken to a dealer for repair.

If you are experiencing the U0156 code on your Harley-Davidson, it is recommended that you first visually inspect the wiring harnesses and connectors for any damage or corrosion. You may also want to check the fuses that power up the information center module. If you are unable to diagnose and fix the issue on your own, it is best to take your bike to a trusted mechanic or dealer for repair.

Understanding Harley Code U0156

What Is Code U0156?

If you own a Harley-Davidson motorcycle, you may have come across code U0156. This code refers to lost communication with the information center A (IC-A). It means that the module responsible for providing information to the speedometer is not communicating with the other modules in the motorcycle’s network.

The most common cause of this code is a loss of power or ground to the IC-A module. This can be due to a blown fuse or a loose connection. In some cases, the code may be intermittent or a memory code, meaning that it is not currently active.

Impact on Harley-Davidson Motorcycles

Code U0156 can have a significant impact on your Harley-Davidson motorcycle. When this code is active, you may experience issues with your speedometer, such as incorrect readings or a complete loss of functionality. Additionally, other modules in the motorcycle’s network may be affected, leading to other issues such as a loss of power or engine performance.

If you encounter this code, it is important to take action to resolve the issue. This may involve checking the fuses that power up the IC-A module, inspecting the wiring harness and connectors, and ensuring that all components are properly connected and functioning.

In conclusion, code U0156 can be a frustrating issue for Harley-Davidson owners, but with proper diagnosis and repair, it can be resolved. If you are experiencing issues with your speedometer or other modules in your motorcycle’s network, it is important to take action to address the issue and ensure the continued safe and reliable operation of your motorcycle.

CAN Bus System Explained

Basics of CAN Bus

The CAN Bus (Controller Area Network) is a vehicle bus standard designed to interconnect automotive devices without a host computer. It is a two-wire communication protocol that allows multiple devices to communicate with each other without a host computer.

The CAN Bus system is used in modern vehicles to connect various electronic control units (ECUs) and sensors. The system allows for real-time communication between the different devices, which enables them to work together seamlessly.

The CAN Bus system is not sensitive to inductive spikes, electrical fields, or other noise. This means that it is highly reliable and can operate in harsh environments.

CAN Bus in Harley-Davidson

Harley-Davidson motorcycles use the CAN Bus system to connect various electronic control units (ECUs) and sensors. The system allows for real-time communication between the different devices, which enables them to work together seamlessly.

The U0156 code is a CAN Bus fault code that indicates a lost communication with the Information Center Module ‘A’. The code sets when a periodic message from the Information Center Module ‘A’ has not been received.

If you are experiencing the U0156 code, it is important to check all fuses that power up the Information Center Module ‘A’. The most common failure is loss of power or ground to the module.

In conclusion, the CAN Bus system is an important component in modern vehicles, including Harley-Davidson motorcycles. It allows for real-time communication between different devices, which enables them to work together seamlessly. If you are experiencing issues with the U0156 code, it is important to check all fuses that power up the Information Center Module ‘A’.

Common Causes of U0156

If you are experiencing the U0156 code on your Harley, it’s essential to understand the various causes of this issue. Here are some of the common causes of U0156:

Electrical Issues

One of the most common causes of U0156 is electrical issues. It could be a problem with the wiring or connectors. If the wiring harness or connectors are damaged, it can cause a loss of communication with the information center module.

To fix this issue, you need to visually inspect the related wiring harness and connectors. Look for any damaged components and check for broken, bent, pushed out, or corroded connector’s pins. If you find any damaged components, you need to replace them.

Module Failures

Another common cause of U0156 is module failures. If the information center module fails, it can cause a loss of communication with other modules. The most common failure is a loss of power or ground to the information center module.

To fix this issue, you need to check all fuses that power up the information center module. If you find any blown fuses, you need to replace them. If the fuses are okay, you need to check the power and ground connections to the information center module.

In conclusion, U0156 can be caused by various factors, including wiring issues and module failures. It’s essential to diagnose the problem correctly to fix it. By understanding the common causes of U0156, you can take the necessary steps to fix the issue and prevent it from happening again.

Troubleshooting Steps

If you are experiencing the U0156 trouble code on your Harley, don’t worry. Here are some troubleshooting steps to help you diagnose and resolve the issue.

Initial Diagnosis

The first step in troubleshooting this code is to read the diagnostic trouble code (DTC) with a scan tool. This will give you a better understanding of the issue and help you identify the root cause. Once you have the code, you can start diagnosing the problem.

One of the most common causes of the U0156 trouble code is a loss of power or ground to the Information Center Module ‘A’ (IC-A). To check this, you can use a multimeter to test the power and ground circuits. If you find that there is no power or ground, you should check the fuses that power up the IC-A module.

Advanced Diagnostics

If you have checked the power and ground circuits and the fuses, but the U0156 code persists, you may need to perform some advanced diagnostics. This could include checking the wiring harness and connectors for any damage or corrosion. You should also look for any broken, bent, pushed out, or corroded connector pins.

Another possible cause of the U0156 code is a faulty IC-A module. In this case, you may need to replace the module to resolve the issue. However, before you do this, you should make sure that the module is the root cause of the problem.

If you are unable to diagnose and resolve the U0156 trouble code on your own, it may be time to seek professional service. A qualified technician can help you diagnose and resolve the issue, ensuring that your Harley is running smoothly once again.

Repair and Maintenance

Fixing the U0156 Code

If you are experiencing a U0156 code on your Harley, it is important to address it as soon as possible. The U0156 code means that there is a communication error between the speedometer and the information center module. This can cause issues with your bike’s electrical system, which can lead to more serious problems down the road.

To fix the U0156 code, you should first check the fuses that power up the information center module. If any of these fuses are blown, replace them and see if the code clears. If the fuses are all in working order, check the wiring harness and connectors for any damage or corrosion. Look for any broken, bent, or pushed out connector pins. If you find any issues, repair or replace the affected components.

If you are still unable to clear the U0156 code, you may need to take your bike to a Harley-Davidson dealer or a qualified mechanic for further diagnosis and repair.

Preventative Measures

To prevent the U0156 code from occurring in the future, there are a few preventative measures you can take. Firstly, make sure to keep your battery in good condition and fully charged. A weak or dead battery can cause issues with your bike’s electrical system, which can lead to communication errors like the U0156 code.

Additionally, make sure to properly maintain your bike’s power and ignition systems. Check the wiring harness and connectors for any damage or corrosion, and replace any affected components. Make sure to also keep your bike’s ground connections clean and tight.

Regularly checking and maintaining these systems can help prevent communication errors like the U0156 code from occurring in the first place.

Understanding ABS Fault Codes

If you own a Harley-Davidson motorcycle, you may have come across ABS fault codes at some point. These codes are used to diagnose problems with the Anti-Lock Braking System (ABS) of your bike. In this section, we will explain some of the common ABS issues and how they relate to the U0156 code.

ABS Related to U0156

The U0156 code is related to a lost communication error with the Information Center Module ‘A’. However, it can also be triggered by a fault in the ABS system. In some cases, the ABS system may cause the U0156 code to appear, even though the problem is with the ABS system itself.

One common ABS issue that can trigger the U0156 code is a low or high voltage problem. If the ABS system detects a voltage that is outside of the normal range, it may trigger the code. In addition, a faulty ABS ECU relay can also cause the U0156 code to appear.

Common ABS Issues

Apart from the U0156 code, there are other common ABS issues that Harley-Davidson riders may encounter. Here are some of them:

  • ABS light stays on: This is one of the most common ABS issues. If the ABS light stays on after starting your bike, it means that there is a problem with the ABS system. The problem could be anything from a faulty sensor to a damaged ABS module.

  • ABS not working: If the ABS system is not working, you will notice that the brakes are not responding as they should. This could be due to a faulty ABS module, damaged sensor, or a problem with the brake lines.

  • ABS warning light flashing: If the ABS warning light is flashing, it means that there is a problem with the ABS system. The flashing light is a warning that you should get your bike checked as soon as possible.

In conclusion, the U0156 code is related to a lost communication error with the Information Center Module ‘A’. However, it can also be triggered by a fault in the ABS system. If you encounter any of the common ABS issues mentioned above, it is important to get your bike checked by a professional mechanic.

Motorcycle’s Electronic Control Modules

When it comes to motorcycle’s electronic control modules, there are various components that work together to ensure the proper functioning of your bike. The electronic control module (ECM) is one such component that plays a critical role in the operation of your motorcycle. In this section, we will discuss the ECM and U0156, as well as other related modules.

ECM and U0156

The ECM is responsible for controlling various aspects of your motorcycle’s engine, including fuel injection, ignition timing, and idle speed. It receives input from various sensors and uses this information to adjust the operation of the engine. The U0156 code indicates that there is a communication problem between the ECM and the instrument cluster module (IC-A). This can be caused by a variety of issues, including a loss of power or ground to the IC-A module, a faulty wiring harness, or a defective ECM.

If you are experiencing the U0156 code, it is important to address the issue as soon as possible. Continuing to operate your motorcycle with this code can result in further damage to the engine or other components. To diagnose the issue, you will need to perform a series of tests to determine the root cause of the problem. This may involve checking the wiring harness, inspecting the ECM for damage, or testing the voltage and current of the system.

Other Related Modules

In addition to the ECM and IC-A modules, there are other components that can be related to the U0156 code. These include the speedometer and tachometer modules, which can also cause communication issues with the ECM. It is important to check all related modules when diagnosing the U0156 code to ensure that you identify and address the root cause of the problem.

Overall, the electronic control modules of your motorcycle are critical components that require proper maintenance and care. If you are experiencing issues with your motorcycle’s ECM or related modules, it is important to address the issue as soon as possible to prevent further damage to your bike. By performing regular maintenance and keeping an eye out for potential issues, you can help ensure the proper functioning of your motorcycle’s electronic control modules.

After Service: Ensuring Functionality

Once the repair has been completed, it is important to ensure that your Harley is functioning as expected. This can be accomplished through post-repair testing and monitoring for recurrence.

Post-Repair Testing

After the repair has been completed, it is important to conduct post-repair testing to ensure that the issue has been resolved. This can be done by checking the display for any engine light or fault codes. If the display shows no errors, then the repair has been successful.

In addition to checking the display, it is also important to take the Harley for a test ride. This will allow you to monitor the bike’s performance and ensure that the issue has been resolved. During the test ride, pay attention to any unusual sounds or vibrations, as well as any changes in the bike’s handling.

Monitoring for Recurrence

Even if the display shows no errors and the test ride is successful, it is still important to monitor the bike for recurrence of the U0156 fault code. This can be done by regularly checking the display for any pending or cleared fault codes.

If the U0156 fault code reappears, it is important to take the Harley back to the service center for further diagnosis and repair. Ignoring the fault code could result in further damage to the bike and potentially unsafe riding conditions.

In summary, after completing the repair for the U0156 fault code, it is important to conduct post-repair testing and monitor the bike for recurrence. Regular maintenance and attention to the display can help prevent further issues and keep your Harley running smoothly.

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