Harley Davidson Trouble Codes- What They Are and How to Read Them

If you’re a Harley-Davidson owner, understanding trouble codes is essential for keeping your bike in top condition. Harley-Davidson motorcycles are equipped with an onboard diagnostic system (OBD) that helps identify issues early, saving you time and money on repairs. Trouble codes, also known as Diagnostic Trouble Codes (DTCs), communicate problems with various systems in the bike. In this article, we’ll explore Harley Davidson Trouble Codes, how to read them, common codes, and how to troubleshoot the issues they point to.

Table of Contents

What Are Harley-Davidson Trouble Codes?

Definition and Purpose of DTCs

Harley-Davidson trouble codes are a set of alphanumeric codes generated by your bike’s onboard diagnostic system. These codes are used to identify faults or malfunctions within various components of the motorcycle, such as the engine, electrical system, and braking systems. The primary purpose of these codes is to communicate potential issues so that riders can address them before they develop into more significant and costly problems.

Types of Harley-Davidson Trouble Codes

Harley-Davidson motorcycles use several types of trouble codes. Each type relates to a specific area of the bike:

ECM Codes (P): These codes typically deal with the Engine Control Module (ECM), affecting areas like fuel injection, ignition, and sensors.
BCM Codes (B): Codes related to the Body Control Module (BCM), which handles electrical systems such as lighting, security, and accessories.
ABS Codes (C): These codes indicate issues with the Anti-lock Braking System (ABS), often related to wheel speed sensors.
Security System Codes (B1xxx): These codes are linked to security-related issues, including problems with the Hands-Free Security Module (HFSM) and the Turn Signal/Security Module (TSM).
COM Codes (U): Communication codes signal problems with data exchange between various modules in the bike.

How to Display and Read Harley-Davidson Trouble Codes

Step-by-Step Guide to Display Trouble Codes

Turn the Ignition to OFF: Start by turning the ignition switch to the OFF position and setting the Run/Stop switch to “Run.”
Press the Odometer Reset Button: For 2014 and newer touring models, use the toggle switch on the left control mount to press and hold the odometer reset button.
Turn the Ignition to “On”: While still holding the reset button, turn the ignition switch to the “On” position. You should see the background lighting illuminate, the speedometer needle sweep, and indicator lamps (e.g., battery, security, low fuel) light up.
Enter Diagnostic Mode: The word “diag” will appear on the display. Push the odometer reset button once to enter the selection menu where the first letter will be flashing (e.g., “P” for ECM, “S” for TSM).
Cycle Through Modules: Use the reset button to cycle through the various diagnostic modules: P for ECM, S for TSM, SP for Speedometer, and T for Tachometer.
View Diagnostic Trouble Codes (DTCs): Hold the reset button for 5 seconds to display the DTC. If there are no issues, the word “none” will appear. If codes are present, they will be shown on the screen.
Clear Codes (If Necessary): To clear the codes, hold the reset button longer than 5 seconds, and the word “clear” will appear. This step can help identify whether the issue is current or historical.

Common Harley-Davidson Trouble Codes and What They Indicate

ECM Codes (P)

P0171: System Too Lean – This code indicates an imbalance in the air/fuel mixture, with the engine running too lean (not enough fuel).
P0300: Random/Multiple Cylinder Misfire Detected – This code suggests that one or more cylinders are misfiring, often due to spark plug or ignition coil issues.
P0563: Battery Voltage High – If the bike’s voltage is too high, it might indicate problems with the charging system or battery.
P0108: MAP Sensor Failed – This code suggests an issue with the Manifold Absolute Pressure (MAP) sensor, which measures air pressure inside the intake manifold.

BCM Codes (B)

B1200: Internal Fault – An internal issue with the Body Control Module (BCM), which controls various electrical systems.
B1121: Left Turn Output Fault – Indicates an issue with the left turn signal output, likely in the Turn Signal/Security Module (TSM).
B1132: Alarm Output High – A problem with the alarm output, signaling potential issues with the security system.

ABS Codes (C)

C1021: ABS Front WSS Always Zero – A problem with the front wheel speed sensor in the ABS system, possibly indicating a malfunction or damage.
C1032: ABS Front Wheel Speed Circuit Open/Shorted – This code indicates a wiring issue with the front ABS wheel speed sensor.

Security System Codes (B1xxx)

B1122: Right Turn Output Fault – This code points to an issue with the right turn signal output in the security module.
B1142: Smart Security System Internal Fault – A problem within the security system’s internal components.

How to Clear Trouble Codes and What to Do Next

Clearing Trouble Codes Safely

Once you’ve identified a trouble code, you may want to clear it to see if the issue resolves. Here’s how to clear codes:

Hold the Odometer Reset Button: Keep the reset button pressed for over 5 seconds until the word “clear” appears on the screen.
Recheck Codes: Turn off the ignition, restart the bike, and recheck for the same code using the diagnostic process above. If the code reappears, it indicates a current problem that needs to be addressed.

When to Seek Professional Help

If the trouble code indicates a serious or complex issue (e.g., ECM or ABS problems), it’s advisable to consult a professional mechanic. While some minor issues can be addressed at home, professional help is necessary for more intricate electrical or engine-related faults.

How to Prevent Future Trouble Codes and Ensure a Smooth Ride

Regular Maintenance

Prevent trouble codes from appearing by performing regular maintenance. This includes:

Checking Sensors: Ensure sensors like the MAP, O2, and TPS are functioning properly.
Replacing Spark Plugs: Worn spark plugs can cause misfires and other engine issues.
Maintaining the Battery: Regularly check the battery and charging system to avoid voltage-related issues.

Monitor for Early Warning Signs

Be alert to warning signs like engine hesitation, misfires, or unusual sounds. These symptoms often precede trouble codes and can help you catch issues early before they worsen.

FAQs about Harley Davidson Trouble Codes

How to read a Harley error code?
- Use the diagnostic method outlined above to access the trouble codes. Follow the steps to cycle through the modules and view any DTCs.
How to get Harley trouble codes?
- Trouble codes can be accessed through the diagnostic menu using the odometer reset button. Ensure your ignition is on, and then cycle through the modules.
How to clear trouble codes on Harley?
- Press and hold the odometer reset button for 5+ seconds to clear any trouble codes. Recheck the system to see if the code reappears.
What is the fault alert on a Harley-Davidson?
- A fault alert indicates that a specific system on the bike is malfunctioning, often related to electrical or mechanical issues.

Conclusion

Harley Davidson trouble codes are essential for identifying and addressing issues early, helping you maintain your bike in peak condition. By following the steps outlined in this guide, you can easily access and interpret trouble codes to resolve minor issues before they become major problems. Regular maintenance and staying alert to potential warning signs are key to ensuring your bike runs smoothly and remains trouble-free. If you’re unsure about any codes or issues, don’t hesitate to consult a professional mechanic to keep your Harley on the road for years to come.