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Harley Code U0186: Understanding and Troubleshooting Tips

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 U0186 code on your bike’s diagnostic system. This code indicates a communication error between your bike’s audio amplifier and the Controller Area Network (CAN). The CAN is a standard bus system that connects different devices in your bike without a host computer.

The U0186 code is commonly caused by a circuit fault that leads to the loss of power or ground to the audio amplifier. This fault can cause your bike’s audio system to malfunction or produce low-quality sound. If you notice that your bike’s audio system is not functioning correctly or you see the U0186 code on your diagnostic system, it is essential to identify the root cause of the problem and fix it as soon as possible.

In this article, we will explore the U0186 code in detail, including its meaning, causes, symptoms, and tech notes. We will also provide you with tips on how to diagnose and fix the U0186 code on your Harley-Davidson motorcycle. By the end of this article, you will have a better understanding of what the U0186 code means and how to fix it, ensuring that your bike’s audio system functions correctly.

Understanding Harley Code U0186

If you are a Harley-Davidson owner, you may have come across the U0186 code while troubleshooting your bike. This code indicates that there is a communication problem between the audio amplifier ‘A’ and the Controller Area Network (CAN) bus. The CAN bus is a standard communication protocol used in vehicles to interconnect different automotive devices.

When the U0186 code appears, it means that the CAN bus has lost communication with the audio amplifier ‘A’. This can be caused by a variety of issues, including wiring problems, a faulty audio amplifier, or issues with the motorcycle’s communication network.

One of the most common causes of the U0186 code is a circuit fault that causes the loss of power or ground to the audio amplifier ‘A’. If you can access codes from the AACM-A, then the U0186 code is either intermittent or a memory code. If unable to access the AACM-A, then the U0186 code that the other modules are setting is active, and the problem is there now.

To fix the U0186 code, you need to diagnose the root cause of the communication problem. This can be done by checking the wiring, testing the audio amplifier, and checking the motorcycle’s communication network. If you are not comfortable doing this yourself, it is recommended to take your bike to a qualified mechanic who can diagnose and fix the issue for you.

In conclusion, the U0186 code is a common issue that Harley-Davidson owners may encounter. It can be caused by a variety of issues, including wiring problems, a faulty audio amplifier, or issues with the motorcycle’s communication network. If you experience this issue, it is important to diagnose and fix the root cause to ensure that your bike is running smoothly.

Diagnosing Electrical Issues

If you are experiencing the U0186 code on your Harley Davidson motorcycle, it is important to diagnose the electrical issues correctly to avoid further damage to your bike. Here are some steps you can take to troubleshoot the problem.

Troubleshooting the CAN Bus

The first step to diagnosing the U0186 code is to troubleshoot the CAN bus. The CAN bus is a communication system that allows different components of your bike to communicate with each other. If there is an issue with the CAN bus, it can cause the U0186 code to appear. To troubleshoot the CAN bus, you can use a diagnostic tool to check for any communication errors.

Checking Wiring and Connectors

The U0186 code can also be caused by issues with the wiring and connectors. Check the wiring and connectors for any signs of damage, such as frayed wires or loose connections. Make sure that all connections are secure and that there are no open circuits. If you find any issues with the wiring or connectors, repair or replace them as necessary.

Battery and Charging System Inspection

Another possible cause of the U0186 code is a problem with the battery or charging system. Check the battery for any signs of damage or corrosion. Test the battery voltage to make sure that it is within the acceptable range. If the battery voltage is low, try slow charging the battery for 12 hours and re-test. Also, check the charging system to make sure that it is working properly. Look for any signs of damage to the charging system, such as frayed wires or loose connections.

By following these steps, you can diagnose and fix the U0186 code on your Harley Davidson motorcycle. Remember to always take safety precautions when working on your bike’s electrical system. If you are unsure about any of these steps, it is best to consult a professional mechanic.

Common DTCs and Their Meanings

If you own a Harley-Davidson motorcycle, you might have come across Diagnostic Trouble Codes (DTCs) at some point. These codes are used to diagnose issues with your bike’s various systems. In this section, we’ll go over some of the most common DTCs and what they mean.

Engine and Transmission Codes

  • P0031 and P0032: These codes indicate a problem with the front oxygen sensor. This could be due to a faulty sensor or wiring issue.
  • P0051 and P0052: These codes indicate a problem with the rear oxygen sensor. Again, this could be due to a faulty sensor or wiring issue.
  • P0107 and P0108: These codes indicate a problem with the Manifold Absolute Pressure (MAP) sensor. This sensor is used to measure the pressure inside the intake manifold.
  • P0112 and P0113: These codes indicate a problem with the Intake Air Temperature (IAT) sensor. This sensor is used to measure the temperature of the air entering the engine.
  • P0117 and P0118: These codes indicate a problem with the Engine Coolant Temperature (ECT) sensor. This sensor is used to measure the temperature of the engine coolant.
  • P0120, P0122, and P0123: These codes indicate a problem with the Throttle Position Sensor (TPS). This sensor is used to measure the position of the throttle.
  • P0131, P0132, and P0134: These codes indicate a problem with the front oxygen sensor. This could be due to a faulty sensor or wiring issue.
  • P0151, P0152, and P0154: These codes indicate a problem with the rear oxygen sensor. Again, this could be due to a faulty sensor or wiring issue.
  • P0220, P0222, and P0223: These codes indicate a problem with the Throttle Position Sensor (TPS). This sensor is used to measure the position of the throttle.
  • P0261, P0262, P0264, and P0265: These codes indicate a problem with the fuel injector for cylinder 1, 2, 4, and 5 respectively.
  • P0371 and P0374: These codes indicate a problem with the timing sensor. This sensor is used to measure the position of the camshaft.
  • P0444 and P0445: These codes indicate a problem with the Evaporative Emission Control System (EVAP). This system is responsible for reducing the amount of fuel vapors that escape into the atmosphere.
  • P0502, P0503, and P0505: These codes indicate a problem with the Vehicle Speed Sensor (VSS). This sensor is used to measure the speed of the vehicle.
  • P0572 and P0577: These codes indicate a problem with the brake light switch. This switch is used to activate the brake lights when the brake pedal is pressed.
  • P0603, P0605, P0641, and P0651: These codes indicate a problem with the Engine Control Module (ECM). This module is responsible for controlling the engine’s various systems.
  • P1009: This code indicates a problem with the Engine Idle Temperature Control (EITC) system. This system is used to control the engine’s idle speed.
  • P1270: This code indicates a problem with the Engine Run Enable (ERE) system. This system is used to prevent the engine from starting if certain conditions are not met.
  • P1501, P1502, P1511, P1512, and P1514: These codes indicate a problem with the Electronic Throttle Control (ETC) system. This system is used to control the throttle electronically.

ABS and Speed Control Codes

  • U0186: This code indicates a loss of communication with the Audio Amplifier. This could be due to a wiring issue or a faulty amplifier.
  • U1016: This code indicates a loss of communication with the Engine Control Module (ECM). This could be due to a wiring issue or a faulty module.
  • U1064: This code indicates a loss of communication with the Turn Signal Module (TSM). This could be due to a wiring issue or a faulty module.
  • U0141H: This code indicates a communication issue with the Left Hand Control Module (LHCM). This could be due to a wiring issue, a problem with the LHCM, or a problem with the bike’s onboard computer.
  • U0185: This code indicates a loss of communication with Application 1. This could be due to a wiring issue or a faulty module.

Remember that DTCs are just a starting point for diagn

Radio and Infotainment System

If you are experiencing the U0186 code on your Harley, it may be related to the audio amplifier ‘A’ in your vehicle. The CAN bus, which interconnects automotive devices without a host computer, may have lost communication with the audio amplifier. To troubleshoot the issue, you may want to start with the radio.

Radio Troubleshooting

If you suspect that the radio is the source of the U0186 code, there are a few steps you can take to troubleshoot the issue. First, check the radio connections to ensure that they are secure. Loose connections can cause communication issues between the radio and other devices in the vehicle.

Next, check the radio fuse to ensure that it is not blown. If the fuse is blown, it could be causing the U0186 code to appear. Replace the fuse if necessary.

If you have made sure that the connections and fuse are okay, you may want to try updating the radio firmware. This can sometimes resolve communication issues between the radio and other devices in the vehicle.

Infotainment Firmware Updates

In addition to updating the radio firmware, you may also want to consider updating the infotainment firmware. This can help to ensure that all devices in the vehicle are communicating properly.

To update the infotainment firmware, you will need to follow the instructions provided by Harley-Davidson. These instructions will vary depending on the specific model of your vehicle and the type of infotainment system that you have.

It is important to note that updating firmware can sometimes cause issues if not done correctly. Be sure to follow the instructions carefully and only update the firmware if you are confident in your ability to do so.

Overall, troubleshooting the radio and updating the infotainment firmware can help to resolve the U0186 code on your Harley. If you are still experiencing issues after trying these steps, you may want to consult with a professional mechanic to diagnose and repair the issue.

Body Control Module (BCM) Issues

If you’re experiencing issues with your Harley Davidson’s Body Control Module (BCM), it can be frustrating. The BCM is a crucial component that controls various electrical systems such as lighting, turn signals, and ignition. However, like any other electrical component, it is prone to issues that can affect its performance.

BCM Communication Faults

One of the most common issues with the BCM is communication faults. These faults can cause the BCM to stop communicating with other modules, which can lead to a variety of problems. For example, if the BCM is not communicating with the engine control module (ECM), the engine may not start or may run poorly.

To diagnose communication faults with the BCM, you can use diagnostic tools such as a scan tool. The scan tool can communicate with the BCM and other modules to identify any communication issues. If a fault is detected, you can then use the diagnostic trouble code (DTC) to identify the specific issue.

BCM Related Error Codes

There are several error codes related to the BCM that you should be aware of. These codes can help you diagnose issues with the BCM and other related systems. Here are some of the most common error codes related to the BCM:

  • B1103 – Front Turn Signal Output Short to Battery
  • B1153 – Sidecar BAS Short to Ground/Open
  • B1200 – Fuel Sender Open/Low
  • B1360 – Ignition Output Circuit Short to Ground
  • B1364 – Fuel Sender Circuit Short to Ground
  • B2102 – Throttle Actuator Control Motor Circuit Low
  • B2103 – Throttle Actuator Control Motor Circuit High
  • B2104 – Throttle Actuator Control Motor Circuit Open
  • B2112 – Fuel Pump Relay Open/Low
  • B2113 – Fuel Pump Relay High/Open

If you’re experiencing any of these error codes, it’s important to diagnose the issue as soon as possible. Ignoring the issue can lead to further damage to the BCM or other related systems.

In conclusion, the BCM is a crucial component of your Harley Davidson’s electrical system. If you’re experiencing issues with the BCM, it’s important to diagnose the issue as soon as possible to prevent further damage. Use diagnostic tools and error codes to identify the issue and take the necessary steps to fix it.

ABS and Stability Control

If you are experiencing issues with your Harley’s ABS and stability control, it may be related to the U0186 code. Here are some common ABS fault codes that may be related to this issue:

ABS Fault Codes

  • ABS Voltage Low: This fault code indicates that the voltage to the ABS system is below the expected range. This may be caused by a faulty battery or alternator. Check the voltage of your battery and alternator to ensure they are functioning properly.

  • ABS Voltage High: This fault code indicates that the voltage to the ABS system is above the expected range. This may be caused by a faulty battery or alternator. Check the voltage of your battery and alternator to ensure they are functioning properly.

  • ABS ECU Relay Error: This fault code indicates that there is an issue with the ABS ECU relay. This may be caused by a faulty relay or wiring issue. Check the wiring and replace the relay if necessary.

  • ABS Front WSS Always Zero: This fault code indicates that the front wheel speed sensor is not functioning properly. This may be caused by a faulty sensor or wiring issue. Check the wiring and replace the sensor if necessary.

  • ABS Rear WSS Always Zero: This fault code indicates that the rear wheel speed sensor is not functioning properly. This may be caused by a faulty sensor or wiring issue. Check the wiring and replace the sensor if necessary.

  • ABS Front Wheel Speed Intermittent: This fault code indicates that the front wheel speed sensor is functioning intermittently. This may be caused by a faulty sensor or wiring issue. Check the wiring and replace the sensor if necessary.

  • ABS Rear Wheel Speed Intermittent: This fault code indicates that the rear wheel speed sensor is functioning intermittently. This may be caused by a faulty sensor or wiring issue. Check the wiring and replace the sensor if necessary.

  • ABS Wheel Speed Difference Too High: This fault code indicates that there is a significant difference in wheel speed between the front and rear wheels. This may be caused by a faulty sensor or wiring issue. Check the wiring and replace the sensor if necessary.

  • ABS Pump/Motor Error: This fault code indicates that there is an issue with the ABS pump or motor. This may be caused by a faulty pump or motor or wiring issue. Check the wiring and replace the pump or motor if necessary.

  • ABS ECU Internal Error: This fault code indicates that there is an issue with the ABS ECU itself. This may be caused by a faulty ECU or wiring issue. Check the wiring and replace the ECU if necessary.

Stability Control Diagnostics

In addition to ABS fault codes, there are also stability control diagnostics that may be related to the U0186 code. These diagnostics may include issues with the yaw rate sensor, lateral acceleration sensor, or steering angle sensor. Check the wiring and replace any faulty sensors if necessary.

It is important to note that these fault codes and diagnostics may not be the only issues related to the U0186 code. If you are experiencing issues with your Harley’s ABS and stability control, it is recommended to have a professional mechanic diagnose and repair the issue to ensure safe and proper functioning of your motorcycle.

Performance and Power Issues

If you’re experiencing performance and power issues with your Harley-Davidson motorcycle, the U0186 code may be to blame. This code indicates that there is a problem with the communication between the audio amplifier and the rest of the vehicle’s systems. Here are some common scenarios that may cause performance and power issues:

Engine Performance Diagnostics

If your engine is not performing as it should, it may be due to the U0186 code. This code can cause the engine to run poorly, resulting in a loss of power and acceleration. You may also notice that your speedometer is not functioning properly, which can make it difficult to determine how fast you’re going.

To diagnose engine performance issues, you can use a diagnostic tool to read the codes stored in the vehicle’s computer. This will help you determine the cause of the problem and take appropriate action to fix it.

Power Loss Scenarios

Another symptom of the U0186 code is a loss of power. This can manifest in a number of ways, such as difficulty starting the engine, reduced acceleration, or a decrease in overall power output. You may also notice that your cruise control is not functioning properly, which can make it difficult to maintain a consistent speed on the highway.

To diagnose power loss issues, you can start by checking the vehicle’s battery and electrical system. Make sure that the battery is fully charged and that all connections are secure. You can also check the vehicle’s fuses and wiring to ensure that there are no issues there. If these basic checks do not resolve the issue, you may need to take the vehicle to a qualified mechanic for further diagnosis and repair.

Remember, if you’re experiencing performance and power issues with your Harley-Davidson motorcycle, it’s important to take action quickly. Ignoring the problem can lead to more serious issues down the road. Use the information provided in this article to diagnose and fix any issues you may be experiencing with your vehicle.

Solutions and Fixes

Resolving U0186 Code

If you are experiencing the U0186 code on your Harley, there are a few things you can do to resolve the issue. One of the first things you should do is check the wiring connections for the audio amplifier. Loose or damaged connections can cause a loss of power or ground to the audio amplifier, which can trigger the U0186 code.

Another thing you can do is check the run/stop switch. This switch can sometimes become stuck in the run position, which can cause a loss of communication with the audio amplifier. Make sure the switch is in the stop position before attempting to diagnose the U0186 code.

If the wiring connections and run/stop switch are not the issue, you may need to check the ECM and controller area network (CAN) for any faults. The CAN is responsible for interconnecting the various automotive devices without a host computer, and a fault in the network can cause a loss of communication with the audio amplifier.

General Maintenance Tips

To prevent the U0186 code from occurring in the first place, it is important to keep up with general maintenance on your Harley. Regularly inspect the wiring connections for the audio amplifier and other components to ensure they are secure and free from damage.

In addition, keep an eye out for any LHCM internal error, RHCM internal error, or IM internal fault codes. These codes can indicate a problem with the various control modules in your Harley, which can cause a loss of communication with the audio amplifier.

By following these tips and performing regular maintenance on your Harley, you can help prevent the U0186 code from occurring and ensure your audio system is functioning properly.

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