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Harley Code U1405: What It Means and How to Fix It

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’re a Harley-Davidson owner, you may have encountered trouble codes on your motorcycle’s dashboard. One of the codes that you may come across is the U1405 code. This code indicates that there is a communication error between the accessory control module (ACM) and the wireless interface module (WIM).

When you see the U1405 code on your Harley-Davidson, it’s important to address it as soon as possible. This code can cause issues with your motorcycle’s performance, and it may even prevent it from starting. The U1405 code can be caused by a variety of factors, including a faulty WIM or ACM, damaged wiring, or a software issue.

Fortunately, there are steps you can take to diagnose and fix the U1405 code on your Harley-Davidson. By using a diagnostic tool, you can identify the specific cause of the code and take the necessary steps to repair it. With the right tools and knowledge, you can get your Harley-Davidson back on the road and running smoothly in no time.

Understanding Harley Code U1405

Definition and Significance

Harley code U1405 is a trouble code that refers to an issue with the communication between the BCM (Body Control Module) and the WHIM (Wireless Headset Interface Module) on your Harley-Davidson motorcycle. The BCM is responsible for controlling various electrical systems on your bike, while the WHIM is responsible for handling the wireless communication between your bike and your headset.

When the ECM (Engine Control Module) detects a problem with the communication between these two modules, it will trigger the U1405 trouble code. This code is significant because it can cause a variety of issues with your bike’s electrical systems, including problems with your audio system, navigation system, and lighting.

Common Symptoms

If you are experiencing issues with your audio system, navigation system, or lighting, it is possible that you have a problem with the communication between the BCM and the WHIM. Some common symptoms of this issue include:

  • Loss of audio
  • Intermittent audio
  • Loss of navigation
  • Intermittent navigation
  • Loss of lighting
  • Intermittent lighting

If you are experiencing any of these symptoms, it is important to have your bike diagnosed by a qualified technician as soon as possible. They will be able to use diagnostic tools to determine the exact cause of the issue and provide you with a solution.

In conclusion, Harley code U1405 is a trouble code that refers to an issue with the communication between the BCM and the WHIM on your Harley-Davidson motorcycle. If you are experiencing issues with your audio system, navigation system, or lighting, it is possible that you have a problem with this communication. Have your bike diagnosed by a qualified technician to determine the exact cause of the issue and provide you with a solution.

Diagnostic Trouble Codes (DTCs) Explained

Reading DTCs

Harley-Davidson motorcycles are equipped with an onboard diagnostic system that can detect and store Diagnostic Trouble Codes (DTCs). These codes can help you diagnose and troubleshoot issues with your motorcycle. To read DTCs on your Harley, you will need a diagnostic tool, such as the Harley-Davidson Digital Technician II (DTII) or the Screamin’ Eagle Pro Super Tuner.

Once you have connected the diagnostic tool to your motorcycle, you can access the DTCs stored in the onboard diagnostic system. The diagnostic tool will display the DTCs along with their corresponding descriptions. You can use this information to identify the cause of the issue and make the necessary repairs.

Types of DTCs: Current, Historic, and Pending

There are three types of DTCs: current, historic, and pending. Understanding the differences between these types of DTCs can help you diagnose and troubleshoot issues with your Harley.

  • Current DTCs: These codes indicate an issue that is currently present in your motorcycle. When a current DTC is detected, the check engine light will illuminate on your dashboard.

  • Historic DTCs: These codes indicate an issue that was previously detected in your motorcycle but has since been resolved. Historic DTCs are stored in the onboard diagnostic system for a certain period of time and can be useful in diagnosing recurring issues.

  • Pending DTCs: These codes indicate an issue that has been detected but has not yet been confirmed. Pending DTCs are stored in the onboard diagnostic system for a certain period of time and can be useful in diagnosing intermittent issues.

By understanding the different types of DTCs and how to read them, you can diagnose and troubleshoot issues with your Harley-Davidson motorcycle.

Harley-Davidson Electrical Systems

Harley-Davidson motorcycles are equipped with advanced electrical systems that are responsible for powering various components of the motorcycle. The electrical system of a Harley-Davidson motorcycle comprises several components that work together to provide reliable and efficient performance. In this section, we will take a closer look at the different components of the electrical system of a Harley-Davidson motorcycle.

Battery and Charging System

The battery and charging system of a Harley-Davidson motorcycle are responsible for providing power to the motorcycle’s electrical components. The battery is charged by the motorcycle’s charging system, which comprises the stator, regulator, and rectifier. The stator generates AC power, which is converted to DC power by the rectifier. The regulator ensures that the battery is charged at the correct voltage.

Ignition System Components

The ignition system of a Harley-Davidson motorcycle is responsible for igniting the fuel-air mixture in the engine’s combustion chamber. The ignition system comprises several components, including the ignition coil, spark plug wires, spark plugs, and ignition control module (ICM). The ICM receives signals from various sensors, including the crankshaft position sensor (CKP), throttle position sensor (TPS), and manifold absolute pressure sensor (MAP). Based on these signals, the ICM determines the correct timing for firing the spark plugs.

Sensors and Their Roles

Several sensors are used in the electrical system of a Harley-Davidson motorcycle to provide critical information to the motorcycle’s electronic control unit (ECU). The ECU uses this information to control various components of the motorcycle. Some of the sensors used in a Harley-Davidson motorcycle include the oxygen sensor, CKP sensor, TPS, MAP sensor, and vehicle speed sensor (VSS).

The oxygen sensor is responsible for measuring the oxygen content in the exhaust gases and providing feedback to the ECU, allowing it to adjust the air-fuel mixture for optimal performance. The CKP sensor provides information about the position and speed of the crankshaft, allowing the ECU to determine the correct timing for firing the spark plugs. The TPS provides information about the position of the throttle, allowing the ECU to adjust the air-fuel mixture accordingly. The MAP sensor measures the pressure in the intake manifold, allowing the ECU to adjust the air-fuel mixture for optimal performance. Finally, the VSS provides information about the motorcycle’s speed, which is used by the ECU to control various components of the motorcycle, including the speedometer.

One of the common codes that Harley-Davidson motorcycles can throw is U1405. This code indicates that the ECU has lost communication with the instrument cluster. If you encounter this code, it is recommended that you check the wiring connections between the ECU and the instrument cluster.

Troubleshooting and Repair

Step-by-Step Diagnostic Process

If you’re experiencing Harley code U1405, it’s important to take the following steps to diagnose and repair the issue:

  1. Check the ignition switch: Ensure that the ignition switch is in the “on” position and that the fuel injection (FI) system is functioning properly.
  2. Check the IAT and ISS: Inspect the Intake Air Temperature (IAT) and Intake Air Speed (ISS) sensors to ensure that they are functioning correctly.
  3. Perform a diagnostic scan: Use a diagnostic scan tool to retrieve the trouble code and determine the root cause of the issue.
  4. Inspect wiring and connectors: Check the wiring and connectors to ensure that they are not damaged or corroded.
  5. Replace faulty components: Replace any faulty components, such as the Body Control Module (BCM) or the Speedometer (SPDO), as necessary.

Tools and Equipment Needed

To diagnose and repair Harley code U1405, you will need the following tools and equipment:

  • Diagnostic scan tool: A diagnostic scan tool is necessary to retrieve the trouble code and diagnose the issue.
  • Multimeter: A multimeter can be used to test the wiring and connectors for continuity and voltage.
  • Replacement components: Depending on the root cause of the issue, you may need to replace components such as the BCM or SPDO.

Common Fixes for U1405

There are several common fixes for Harley code U1405, including:

  • Replacing the BCM: If the BCM is faulty, it may need to be replaced to resolve the issue.
  • Replacing the SPDO: If the Speedometer is faulty, it may need to be replaced to resolve the issue.
  • Checking wiring and connectors: Inspecting the wiring and connectors for damage or corrosion can help identify and resolve the issue.

By following the step-by-step diagnostic process, using the necessary tools and equipment, and implementing common fixes, you can successfully diagnose and repair Harley code U1405, ensuring optimal performance of your motorcycle.

Maintenance Tips to Prevent DTCs

To avoid DTCs such as U1405 on your Harley-Davidson, it is essential to keep your motorcycle in good condition. Regular inspections and maintenance checks can help prevent DTCs from occurring. Here are some tips to help you maintain your Harley-Davidson:

Regular Inspection Intervals

It is important to inspect your motorcycle at regular intervals. Inspect the battery, VIN, ABS, ACR, BAS, HO2S, JSS, LHCM, MAP, TCA, TGS, and other critical areas to ensure they are in good condition. Regular inspections will help you identify any issues before they become major problems.

Critical Maintenance Areas

Here are some critical maintenance areas that you should pay attention to:

  • Battery: Check the battery terminals for corrosion and clean them if necessary. Inspect the battery for signs of damage or wear. Replace the battery if necessary.
  • ABS: Inspect the ABS sensors for damage or wear. Clean the sensors if necessary.
  • ACR: Inspect the ACR for damage or wear. Replace the ACR if necessary.
  • BAS: Inspect the BAS for damage or wear. Replace the BAS if necessary.
  • HO2S: Inspect the HO2S for damage or wear. Replace the HO2S if necessary.
  • JSS: Inspect the JSS for damage or wear. Replace the JSS if necessary.
  • LHCM: Inspect the LHCM for damage or wear. Replace the LHCM if necessary.
  • MAP: Inspect the MAP for damage or wear. Replace the MAP if necessary.
  • TCA: Inspect the TCA for damage or wear. Replace the TCA if necessary.
  • TGS: Inspect the TGS for damage or wear. Replace the TGS if necessary.

By following these tips, you can help prevent DTCs on your Harley-Davidson. Regular inspections and maintenance checks will help keep your motorcycle in good condition and ensure it runs smoothly.

Advanced Diagnostics

Interpreting Advanced Diagnostic Data

If you are experiencing issues with your Harley-Davidson motorcycle, the onboard diagnostic system (OBD) can help you identify the problem. The system generates Diagnostic Trouble Codes (DTCs) that can be interpreted to diagnose the issues. One such code is U1405, which indicates that the Accessory Control Circuit (ACC) bus has lost communication with the Wireless Interface Module (WIM).

When interpreting advanced diagnostic data, it is important to understand the different modules in the OBD system. The Engine Control Module (ECM) is responsible for monitoring the engine and transmission. The Body Control Module (BCM) controls the lights, horn, and other electrical components. The Radio (RAD) module controls the audio system. The Controller Area Network (CAN) is the communication network that connects all the modules.

Using Diagnostic Software

To diagnose issues with your Harley-Davidson motorcycle, you can use diagnostic software such as the Digital Technician II. This software allows you to read and clear DTCs, view sensor data, and perform various tests on the modules.

When using diagnostic software, you should first connect the software to the OBD port on your motorcycle. Then, you can select the module you want to diagnose and view the DTCs. The software will provide a description of the code and possible causes. You can also view live sensor data to help diagnose the issue.

In conclusion, interpreting advanced diagnostic data and using diagnostic software can help you diagnose issues with your Harley-Davidson motorcycle. Understanding the different modules in the OBD system and using the correct software can make the process easier and more efficient. If you are experiencing issues with your motorcycle, we recommend consulting a certified Harley-Davidson mechanic for assistance.

Harley-Davidson Performance Upgrades

When you upgrade your Harley-Davidson motorcycle, it can significantly improve its performance and overall riding experience. However, it’s important to keep in mind that some upgrades may impact the diagnostic trouble codes (DTCs) that your bike generates, including the U1405 code. Here are some things to consider when upgrading your Harley:

Impact of Upgrades on DTCs

Certain upgrades, such as changes to the exhaust system or air intake, can affect the way your bike runs and generate DTCs. For example, if you install a high-performance exhaust system without tuning your bike’s engine, you may see a DTC related to the exhaust system. Similarly, if you install a new air intake without adjusting your bike’s fuel injection system, you may see a DTC related to the air intake.

Recommended Performance Parts

To avoid generating DTCs when upgrading your Harley-Davidson, it’s important to choose performance parts that are designed to work together and with your bike’s existing systems. Here are some recommended performance parts that can help improve your bike’s performance without generating DTCs:

  • High-performance air intake: A high-performance air intake can help increase airflow to your bike’s engine, which can improve its performance without generating DTCs.
  • Performance exhaust system: A performance exhaust system can help reduce back pressure in your bike’s engine, which can improve its performance without generating DTCs.
  • Tuning module: A tuning module can help adjust your bike’s fuel injection system to work with your new performance parts, which can help prevent DTCs.

By choosing the right performance parts and ensuring they are properly installed and tuned, you can upgrade your Harley-Davidson motorcycle without generating DTCs like the U1405 code.

Legal and Safety Considerations

Compliance with Emission Standards

Harley-Davidson motorcycles are designed to comply with environmental regulations. The engine and exhaust system are equipped with sensors that monitor the emissions and ensure that they are within the legal limits. The oxygen sensor, for example, is responsible for measuring the amount of oxygen in the exhaust gas and sending this information to the engine control module (ECM). If the oxygen level is too high or too low, the ECM adjusts the fuel injection to maintain the proper air-fuel ratio.

If your Harley-Davidson motorcycle has a DTC U1405, it means that the accessory control module (ACM) has lost communication with the wireless interface module (WIM). This code is not related to emissions, but it is still important to address it promptly to ensure that your motorcycle is functioning properly.

Riding Safety and DTCs

Harley-Davidson motorcycles are equipped with a diagnostic system that can detect and report malfunctions. The diagnostic trouble codes (DTCs) are displayed on the odometer and can help you identify the source of the problem. It is important to address any DTCs promptly to ensure that your motorcycle is safe to ride.

If your Harley-Davidson motorcycle has a DTC U1405, it means that the accessory control module (ACM) has lost communication with the wireless interface module (WIM). This code can affect the functionality of certain accessories, such as the security system or the tire pressure monitoring system. It is important to have this code diagnosed and repaired by a qualified technician to ensure that your motorcycle is safe to ride.

In addition to addressing any DTCs promptly, it is important to practice safe riding habits. Always wear appropriate safety gear, such as a helmet and protective clothing. Be aware of your surroundings and ride defensively. Keep your motorcycle well-maintained and address any issues promptly. By following these guidelines, you can help ensure that your Harley-Davidson motorcycle is safe and reliable.

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