Updating the ECM/PCM

ECM Updating and Substitution for Testing

Special Tools Required
Honda Interface Module (HIM) P/N EQS05A35570

Use this procedure when you have to substitute a known-good ECM in a troubleshooting procedure. Update the ECM only if the ECM does not already have the latest software loaded.

NOTE: Do not turn the ignition switch OFF while updating; the ECM can be damaged.

How to Update the ECM

NOTE:
- To ensure the latest program is installed, do an ECM update whenever the ECM is substituted or replaced.
- Before you update the ECM, make sure the vehicle's battery is fully charged.
- To prevent ECM damage, do not operate anything electrical (audio system, brakes, A/C, power windows, moonroof, door locks, etc.) during the update.
- If you need to diagnose the Honda Interface Module (HIM) because the HIM's red (#3) light came on or was flashing during the update, leave the ignition switch in the ON (II) position when you disconnect the HIM from the Data Link Connector (DLC). This will prevent ECM damage.

1. Turn the ignition switch ON (II). Do not start the engine.




2. Connect the HIM to the DLC (A) located under the driver's side of dashboard.
3. Do the ECM update procedure as described on the HIM label and in the ECM update system. If the software in the ECM is the latest version, replace the ECM.

How to Substitute the ECM
1. Remove the ECM from the vehicle.
2. Install a known-good ECM in the vehicle.
3. Rewrite the immobilizer code with the ECM replacement procedure in the HDS: It allows you to start the engine.
4. After completing your tests, reinstall the original ECM and rewrite the immobilizer code with the ECM replacement procedure in the HDS again.