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Harley Code U0142: 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 own a Harley-Davidson motorcycle, you may have encountered trouble codes that appear on your dashboard. One such code is U0142, which is related to a communication error with the Body Control Module (BCM). This code can be frustrating to deal with, but with the right diagnosis and repair, you can get your bike back on the road in no time.

The BCM is an important component of your Harley’s electrical system, responsible for controlling various functions such as lighting, security, and the instrument cluster. When the BCM loses communication with other modules in the system, such as the speedometer or fuel gauge, it can trigger the U0142 code. This can be caused by a variety of issues, including faulty wiring, a malfunctioning BCM, or a dead battery.

Diagnosing the U0142 code can be tricky, as it requires specialized equipment and knowledge of your Harley’s electrical system. However, once the issue is identified, repairs can often be made quickly and easily. If you’re experiencing trouble with your Harley and suspect the U0142 code may be the culprit, it’s important to seek the help of a qualified technician who can diagnose and repair the issue.

Understanding Harley Trouble Codes

If you own a Harley-Davidson motorcycle, you may have seen some strange codes on your bike’s instrument cluster. These codes are known as Diagnostic Trouble Codes (DTCs) and are used to diagnose issues with your bike’s various systems. In this section, we will explain what DTCs are, what they mean, and how to read them.

DTC and Harley Code U0142

DTCs are a standardized system used by all modern vehicles, including Harley-Davidson motorcycles. When a problem is detected in one of your bike’s systems, a code is generated and stored in the Electronic Control Module (ECM). You can then read this code using a diagnostic tool or by following a specific procedure outlined in your bike’s owner’s manual.

One of the most common codes you may encounter is U0142. This code indicates a communication error between the ECM and the Right Hand Control Module (RHCM). This can be caused by a faulty RHCM, damaged wiring, or a loose connection. If you see this code, it is recommended that you take your bike to a certified Harley-Davidson technician for diagnosis and repair.

Common Harley ECM Trouble Codes

In addition to U0142, there are several other common DTCs that you may see on your Harley-Davidson motorcycle. These include:

  • U0140: Lost Communication With Body Control Module (BCM)
  • U0141: Lost Communication With Front Control Module (FCM)
  • B1153: Sidecar Power Circuit Fault
  • P1655: Starter Relay Control Circuit High
  • U0001: High-Speed CAN Communication Bus
  • U0156: Lost Communication With Speedometer
  • U0121: Lost Communication With Anti-Lock Brake System (ABS) Control Module
  • U0100: Lost Communication With ECM/PCM

If you see any of these codes, it is recommended that you take your bike to a certified Harley-Davidson technician for diagnosis and repair. These codes can indicate issues with your bike’s electrical system, ABS, or other critical components, and should be addressed as soon as possible to prevent further damage or safety hazards.

In conclusion, understanding DTCs and Harley codes can help you diagnose issues with your bike and keep it running smoothly. If you see any codes on your bike’s instrument cluster, don’t ignore them – take your bike to a certified technician for diagnosis and repair.

Body Control Module (BCM) Basics

BCM Function and Importance

The Body Control Module (BCM) is a vital component in your Harley’s electrical system. It is responsible for managing and controlling various electrical functions in your motorcycle, including lighting, power windows, and audio systems. The BCM communicates with other modules in your Harley, such as the Engine Control Module (ECM), to ensure that all systems are working together efficiently.

The BCM is essentially the “brain” of your Harley’s electrical system. It receives input from various sensors and switches throughout the motorcycle and sends output signals to control various functions. Without the BCM, your Harley’s electrical system would not function correctly.

BCM Related Codes and Symptoms

One of the most common issues with the BCM is the U0142 code, which indicates that there has been a loss of communication with the BCM. This code can cause various symptoms, such as engine cutting out, difficulty starting, or even a complete failure to turn on.

If you suspect that your Harley is experiencing issues with the BCM, there are a few steps you can take to diagnose the problem. Firstly, you should check the battery voltage to ensure that it is at least 12.5 volts. A low battery voltage can cause BCM problems. You should also check the fuses for the BCM and ensure that they are not blown. Finally, you should check the connections to the BCM and ensure that they are clean and tight.

In conclusion, the BCM is a crucial component in your Harley’s electrical system. It is responsible for managing and controlling various electrical functions, and without it, your motorcycle would not function correctly. If you suspect that your Harley is experiencing issues with the BCM, you should take steps to diagnose the problem and resolve it as soon as possible.

Electrical Diagnosis for Harley Motorcycles

If you’re experiencing problems with your Harley motorcycle’s electrical system, it’s important to diagnose the issue as soon as possible to avoid further damage. Here are some tips on how to diagnose electrical issues in your Harley motorcycle.

Wiring Harness and Connector Issues

One of the most common issues with electrical systems in Harley motorcycles is wiring harness and connector issues. Over time, the wiring harness and connectors can become corroded or damaged, which can result in a variety of issues.

To diagnose these issues, start by inspecting the wiring harness and connectors for any signs of corrosion or damage. If you find any issues, replace the affected parts as soon as possible.

Voltage and Circuit Checks

Another important aspect of diagnosing electrical issues in your Harley motorcycle is performing voltage and circuit checks. This involves checking the voltage and continuity of various circuits in your motorcycle’s electrical system.

To perform these checks, you’ll need a multimeter and a wiring diagram for your motorcycle. Start by identifying the circuits that are causing issues, and then use the wiring diagram to locate the relevant connectors and wires.

Once you’ve located the relevant connectors and wires, use the multimeter to check the voltage and continuity of each circuit. If you find any issues, you may need to replace the affected parts or repair any damaged wiring.

Remember, diagnosing electrical issues in your Harley motorcycle can be a complex process. If you’re not comfortable performing these checks yourself, it’s best to take your motorcycle to a qualified technician for diagnosis and repair.

Harley-Davidson Sensor and Actuator Functions

When it comes to the functioning of your Harley-Davidson, the sensors and actuators play a crucial role in ensuring that everything runs smoothly. Here are some of the key functions of the sensors and actuators in your motorcycle.

MAP and ET Sensors

The Manifold Absolute Pressure (MAP) sensor is responsible for measuring the pressure inside the intake manifold. It sends this information to the Engine Control Module (ECM), which then uses it to calculate the amount of fuel to inject into the engine. The Exhaust Temperature (ET) sensor, on the other hand, measures the temperature of the exhaust gases. This information is also sent to the ECM, which uses it to adjust the fuel injection timing.

Fuel Injector and CKP Sensor

The Fuel Injector is responsible for spraying fuel into the engine at the right time and in the right amount. It receives signals from the ECM, which tells it when to open and close. The Crankshaft Position (CKP) sensor, on the other hand, measures the position and speed of the crankshaft. This information is sent to the ECM, which uses it to determine the correct timing for fuel injection and ignition.

It is important to note that the MAP and ET sensors, as well as the Fuel Injector and CKP sensor, work together to ensure that your motorcycle runs smoothly. If any of these sensors or actuators are not functioning properly, it can cause issues such as poor performance, reduced fuel efficiency, and even engine damage.

Overall, understanding the functions of the sensors and actuators in your Harley-Davidson can help you identify and resolve issues before they become major problems. If you suspect that any of these components are not functioning properly, it is important to have your motorcycle inspected by a qualified technician.

Network Management and Harley Error Codes

Understanding Harley Network Systems

Harley-Davidson motorcycles are equipped with various electronic control modules (ECMs), including the Body Control Module (BCM), Speedometer, Radio, Anti-lock Braking System (ABS), Left Hand Control Module (LHCM), and Right Hand Control Module (RHCM). These modules are interconnected through a network management system that allows them to communicate with each other and with the main ECM.

The network management system is responsible for monitoring the communication between the modules and detecting any errors that may occur. When an error is detected, the system generates a fault code that is stored in the main ECM. These fault codes can be read using a diagnostic tool or by accessing the menu on the speedometer.

Diagnosing Network Related Error Codes

One of the most common network-related error codes on Harley-Davidson motorcycles is U0142, which indicates a loss of communication with the Body Control Module (BCM). This code can be caused by a variety of factors, including a faulty BCM, a loose connection, or a damaged wiring harness.

To diagnose this error code, you should start by checking the wiring harness and connections between the BCM and the main ECM. Look for any signs of damage or corrosion, and ensure that all connections are secure. If the wiring harness and connections are in good condition, you should then test the BCM itself using a diagnostic tool.

If the BCM is found to be faulty, it will need to be replaced. This is a complex procedure that should only be performed by a qualified technician. However, if the BCM is not the problem, you may need to perform further diagnostic tests to determine the root cause of the error code.

In summary, Harley-Davidson motorcycles use a network management system to interconnect various control modules. When an error is detected, the system generates a fault code that can be read using a diagnostic tool or by accessing the menu on the speedometer. To diagnose network-related error codes, you should start by checking the wiring harness and connections, and then test the affected module using a diagnostic tool.

Repair and Service Procedures

Dealer vs. Self-Repair

When it comes to repairing the U0142 code on your Harley, you have two options: take it to a dealer or attempt to fix it yourself. If you are not confident in your ability to diagnose and repair the issue, it is recommended to take your bike to a dealer. They have the expertise and tools necessary to accurately diagnose and repair the problem.

However, if you are experienced in motorcycle repair and have the necessary tools, you can attempt to fix the issue yourself. It is important to note that attempting to fix the issue yourself can be risky and may cause further damage to your bike if you are not careful.

Troubleshooting Steps

Before attempting any repairs, it is important to diagnose the issue properly. The following steps can help you troubleshoot the U0142 code:

  1. Check the run/stop switch – Ensure that the switch is in the run position and not in the stop position. If it is in the stop position, switch it to run and try starting the bike again.

  2. Check the wiring – Inspect the wiring for any damage or loose connections. If any issues are found, repair or replace the damaged wiring.

  3. Check the right hand control module – The U0142 code is often caused by a lost signal from the right hand control module. Inspect the module for any damage or loose connections. If any issues are found, repair or replace the module.

  4. Check the body control module – The U0142 code can also be caused by a lost signal from the body control module. Inspect the module for any damage or loose connections. If any issues are found, repair or replace the module.

If none of the above steps solve the issue, it is recommended to take your bike to a dealer for further diagnosis and repair.

Remember, it is important to properly diagnose and repair any issues with your Harley to ensure the safety of yourself and others on the road.

Maintaining Your Harley’s Electrical Health

As a Harley-Davidson owner, it’s important to keep an eye on your bike’s electrical system. Regular maintenance can help prevent issues with codes like U0142 and keep your ride running smoothly. Here are some tips for maintaining your Harley’s electrical health.

Battery Maintenance

Your battery is the heart of your Harley’s electrical system. To keep it working properly, you need to maintain it regularly. Here are some things you should do to keep your battery in good shape:

  • Check your battery’s voltage regularly. A fully charged battery should read between 12.6 and 12.8 volts.
  • Keep your battery clean and free of corrosion. Use a wire brush to clean the terminals and a battery cleaner to remove any buildup.
  • Make sure your battery is securely mounted. A loose battery can cause all sorts of electrical problems.

Preventive Measures for Electrical Components

In addition to maintaining your battery, there are some other things you can do to prevent issues with your Harley’s electrical system. Here are some tips:

  • Check your wiring regularly. Look for any signs of wear or damage, and replace any damaged wires.
  • Keep your electrical connections clean and tight. Loose connections can cause all sorts of problems.
  • Use dielectric grease on your electrical connections. This will help protect them from corrosion and keep them working properly.
  • Make sure your Harley’s electrical components are properly grounded. A bad ground can cause all sorts of issues with your electrical system.

By following these tips, you can help prevent issues with codes like U0142 and keep your Harley running smoothly. Remember to always read your codes and address any pending issues before they turn into bigger problems.

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