How to clear DTC with HDS?
To clear DTCs with HDS, you connect the Honda Diagnostic System to the car, read the current codes, select the erase/clear DTC option, confirm, then reset the codes and perform a drive cycle to verify the fault does not return.
Understanding DTCs and why clearing them matters
Diagnostic Trouble Codes (DTCs) are stored in a vehicle’s control modules when a sensor, actuator, or system detects a fault. There are active codes (currently failing) and stored/pending codes (historical or awaiting drive-cycle confirmation). Clearing DTCs removes the codes from the memory, but it does not fix the underlying issue. After repair, clearing is often used to reset the MIL (Malfunction Indicator Lamp) and to allow the vehicle’s readiness monitors to re-run during a drive cycle.
What you need to clear DTCs with HDS
Before you begin, ensure you have legitimate access to the Honda Diagnostic System (HDS) and a compatible interface for your vehicle. You’ll typically need a laptop with the appropriate Windows version, the HDS software, and a supported OBD-II/HDS interface cable. Have the vehicle’s battery in good condition and follow all safety precautions. Note that different Honda/Acura ECUs (Powertrain, ABS, body control, etc.) store codes in their own memory, so you’ll need to select the correct ECU when reading or erasing codes.
Step-by-step guide to clear DTCs using HDS
Follow these steps to read and clear DTCs using HDS. The steps cover connecting, reading codes, erasing them, and verifying the result.
- Verify safety and basic readiness: park on a level surface, engage the parking brake, and ensure the vehicle is in a safe state for diagnostics. Confirm the battery is healthy.
- Connect the HDS interface to the vehicle’s OBD-II port and connect the interface to the diagnostic laptop. Make sure the connection is secure.
- Launch the HDS software and confirm the interface is communicating with the vehicle’s ECUs. Wait for the software to establish a stable connection.
- From the HDS main menu, select the ECU that stored the DTCs (commonly Powertrain/Engine, but could be ABS or another module) and choose the option to “Read DTCs” or similar to pull current and stored codes.
- Review and record the DTCs and any freeze-frame data for reference. This helps diagnose the fault if codes reappear after erasing them.
- Back in the DTC screen, choose “Erase DTCs” or “Clear DTCs” and confirm the action. The system will write new memory nonvolatile data and reset the codes.
- Turn the ignition OFF, disconnect the interface if needed, then start the vehicle or perform necessary KOEO/KOER tests as required by the vehicle and HDS prompts.
- Drive the vehicle through a normal drive cycle to verify that codes do not return and that the readiness monitors complete as applicable to the vehicle.
After the list, it’s important to verify that the root cause was addressed. If a fault reappears, re-check the implicated sensor, wiring, and related components, and perform additional diagnostics before attempting another erase.
Drive cycles, readiness monitors, and verification
Many modern vehicles require a specific drive cycle for monitors to complete and for the system to confirm the fault is resolved. After clearing DTCs, you may need to perform KOEO/KOER tests and drive the car under a variety of operating conditions (idle, light to moderate acceleration, highway speeds) to let monitors run. If a code returns, do not ignore it—the underlying issue likely remains unresolved.
Common issues and troubleshooting when clearing DTCs with HDS
These are typical scenarios you may encounter and how to handle them.
- Codes reappear after clearing: The fault persists. Reinspect the suspected component or circuit, repair as needed, and recheck before erasing again.
- MIL stays on after clearing: The fault condition may still be active or a permanent/can’t-clear code is present. Reassess with an updated diagnostic table and perform a thorough drive cycle to confirm.
- HDS cannot connect to the ECU: Check the interface drivers, ensure the correct HDS version is installed, and verify that you are using a compatible cable for your vehicle and Windows version.
- Permanent or non-clearing codes: Some modules store hard faults that require repair or battery/module reset. Follow the official repair steps for the specific code.
- Monitors not becoming ready after drive: Confirm all required drive-cycle conditions and fix any remaining faults; some monitors require specific sequences (e.g., a certain speed, temperature, or idle duration).
In practice, approach clearing DTCs as a diagnostic milestone rather than a fix. Document the codes, repair the root causes, and then re-test thoroughly to avoid masking ongoing problems.
Summary
Clearing DTCs with HDS involves connecting to the vehicle, reading current and stored codes, erasing the codes, and then performing a proper drive cycle to verify that the fault is resolved and that the vehicle’s readiness monitors complete. Always address the root cause before clearing codes, and be mindful that some codes may return if the underlying issue isn’t fixed or if the vehicle requires specific drive-cycle conditions to reset monitors. Use the correct HDS version and a compatible interface, and consult official manuals for model-specific steps and safety recommendations.
