QPKING M4 Motorcycle Scan Tool for Harley-Davidson - 4P/6P Connector, Handheld 2.8" Colour Display

The QPKING M4 is a handheld diagnostic device built to read, clear and test full-system faults on compatible Harley-Davidson motorcycles using their 4‑pin or 6‑pin round diagnostic port.

This compact scanner provides mechanics and riders a focused Harley diagnostic workflow: retrieve trouble codes, observe live sensor data, run active tests and perform supported service resets. The M4 is tailored for Harley models with the round 4P/6P connector and includes a secondary OBD2 cable for basic car engine checks—coverage varies by model year and ECU. Its 2.8‑inch color display operates in 17 languages and the unit runs from the bike's 12 V supply (no internal battery).

How does the M4 identify and clear faults on my Harley-Davidson?

The M4 connects with the motorcycle’s round 4‑pin or 6‑pin diagnostic port to access supported ECUs. It reads stored and pending fault codes, displays ECU info and can clear codes when the underlying issue is resolved.

• Reads and clears supported diagnostic trouble codes (DTCs)
• Shows ECU identification and firmware details
• Displays live data streams for sensors and modules
• Coverage depends on motorcycle year, model and ECU type

What service functions and active tests can I perform with the M4?

The tool supports a range of service procedures and module-level active tests where the motorcycle’s ECU allows them. Some reset and adjustment routines are available directly from the device; ABS bleeding is supported on eligible models through 2023.

• Performs supported service resets (where available)
• Runs active tests and output actuations to diagnose components
• ABS bleed function available on compatible models (up to 2023)
• Not all models or functions are guaranteed—check compatibility first

Which cables are included and what do they do?

The M4 ships with two separate cables to broaden its utility. Use the Harley 4P/6P cable for full motorcycle diagnostics; the OBD2 16‑pin cable provides basic engine code reading for many cars but lacks advanced motorcycle functions.

• Harley 4P/6P cable: full diagnostics, resets, active tests, ABS bleed (when supported)
• OBD2 16P cable: read/clear basic engine codes and view live engine data for cars
• Switch cables depending on vehicle and intended function

The unit operates as a standalone tool and lacks an internal battery, so it must be powered by the motorcycle’s 12 V system. Updates are installed via the official update package and a FAT32 SD card while the tool remains powered—no internal power removal required.

Who should choose the QPKING M4? The M4 is designed for Harley-Davidson owners, independent motorcycle technicians and small shops that need a compact, Harley-focused diagnostic device without subscription fees. It’s best for users who have models with the round 4‑pin or 6‑pin diagnostic connector and want on-bike fault reading, live data observation and supported service routines. If you require broad multi-brand motorcycle coverage beyond the round Harley connector, or advanced 2024+ ABS procedures, evaluate compatibility prior to purchase.