Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
ECM Reset
2005 Honda Civic Si L4-2.0LSECTION ECM Reset
How to Reset the ECM
You can reset the ECM in either of two ways:
- Use the HDS or a scan tool to reset the ECM memory. See the HDS or a scan tool user's manuals for specific instructions.
- Turn the ignition switch OFF, and remove the No.6 ECU (ECM) (15 A) fuse (A) from the under-hood fuse/relay box (B) for 10 seconds.
How to End a Troubleshooting Session (required after any troubleshooting)
1. Reset the ECM as described above.
2. Do the ECM idle learn procedure.
3. Turn the ignition switch OFF.
4. Disconnect the HDS or a scan tool from the DLC.
NOTE: The ECM is part of the immobilizer system. If you replace the ECM, it will have a different immobilizer code. In order for the engine to start, you must rewrite the immobilizer code with the HDS.
You can reset the ECM in either of two ways:
- Use the HDS or a scan tool to reset the ECM memory. See the HDS or a scan tool user's manuals for specific instructions.
- Turn the ignition switch OFF, and remove the No.6 ECU (ECM) (15 A) fuse (A) from the under-hood fuse/relay box (B) for 10 seconds.
How to End a Troubleshooting Session (required after any troubleshooting)
1. Reset the ECM as described above.
2. Do the ECM idle learn procedure.
3. Turn the ignition switch OFF.
4. Disconnect the HDS or a scan tool from the DLC.
NOTE: The ECM is part of the immobilizer system. If you replace the ECM, it will have a different immobilizer code. In order for the engine to start, you must rewrite the immobilizer code with the HDS.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.