Quote from Mickael faust on March 17, 2026, 10:57 pm

Dear JDiag Technical Support Team,

I am writing to report two critical communication issues encountered while using my JDiag diagnostic tool on a Harley-Davidson 2018 Milwaukee-Eight (M8) engine platform, running calibration file HARLEY_FR.bin V10.01.

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ISSUE #1 – ABS REAR CIRCUIT : COMMUNICATION ERROR DURING BLEEDING PROCEDURE

Vehicle: Harley-Davidson 2018 / Milwaukee-Eight (M8) / ABS equipped
Firmware file: HARLEY_FR.bin V10.01

Observed behavior:
- Front ABS bleeding procedure completes successfully with no errors.
- Rear ABS bleeding procedure fails with a communication error.
- Both front and rear ABS solenoids respond correctly when actuated independently through the JDiag actuator test menu — confirming no physical fault on the ABS HCU (Hydraulic Control Unit).
- No DTC (Diagnostic Trouble Code) stored in the ABS module.

Technical analysis:
The 2018 Harley-Davidson ABS system uses a dual-channel HCU communicating over CAN bus. The front and rear circuits require a specific sequential command timing during the bleeding procedure. It appears the JDiag tool correctly handles the front circuit command sequence but fails to synchronize with the rear circuit, resulting in a CAN communication timeout error. This is not a hardware fault on the motorcycle — it is a protocol implementation issue in the JDiag ABS bleeding routine for the 2018 M8 platform.

Expected behavior:
Both front and rear ABS circuits should complete the bleeding procedure successfully, as both solenoids are confirmed functional.

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ISSUE #2 – HFSM (Hands-Free Security Module) : PIN CODE NOT DISPLAYED, FOB PROGRAMMING NOT WORKING

Vehicle: Harley-Davidson 2018 / Milwaukee-Eight (M8) / HFSM with proximity FOB (no button)
Firmware file: HARLEY_FR.bin V10.01

Observed behavior:
- When attempting to read the current PIN code via JDiag security menu, the PIN field is displayed empty (blank).
- When attempting to modify the PIN code, JDiag confirms "operation successful" but the PIN is NOT actually changed on the ECU — the old PIN remains active.
- FOB programming function does not complete correctly.
- The proximity FOB was present and within range throughout all tests.

Technical analysis:
The 2018 Harley-Davidson HFSM uses an enhanced CAN security protocol compared to the older TSSM (Turn Signal Security Module) used on pre-2017 models. The HFSM requires:
1. Active FOB authentication handshake before any PIN read/write operation is authorized.
2. A specific multi-step security access sequence (SecurityAccess service – UDS protocol) before the ECU accepts PIN modification commands.
It appears the JDiag tool sends the PIN modification command correctly, but does not complete the full UDS SecurityAccess handshake required by the 2018 HFSM. As a result, the ECU silently rejects the command while JDiag incorrectly reports "operation successful" — this is a false positive confirmation which is particularly problematic from a diagnostic standpoint.

Expected behavior:
- PIN code should be readable and displayed correctly.
- PIN modification should be confirmed only after the ECU acknowledges the change.
- FOB programming should complete successfully with FOB in proximity.

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SYSTEM INFORMATION

- Tool: JDiag diagnostic interface
- Calibration file: HARLEY_FR.bin V10.01 (dated 2025-04-24)
- Updated calibration file tested: HARLEY_FR.bin V10.01 (dated 2025-09-25) — same issues persist
- Vehicle: Harley-Davidson 2018, Milwaukee-Eight platform, FR market
- CAN protocol: Dual CAN bus (Powertrain CAN + Chassis CAN)
- ABS: Continental/Bosch dual-channel HCU
- Security module: HFSM (Hands-Free Security Module) with proximity FOB

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I would appreciate a firmware or software update addressing both issues, and confirmation of the expected timeline for a fix.

Thank you for your attention to these matters.

Best regards