How to Update the ECM/PCM of Honda Accord 2002-2007
Updating the ECM/PCM
ECM/PCM Updating and Substitution for Testing
Special Tools Required: OBD Diagnostic tools.
Use this procedure when you have to substitute a known-good ECM/PCM in a
troubleshooting procedure. Update the ECM/PCM only if the ECM/PCM does not have
the latest software loaded.
NOTE: Do not turn the ignition switch OFF while updating the ECM/PCM. If you turn
the ignition switch OFF before completion, the ECM/PCM can be damaged.
How to Update the ECM/PCM
– To ensure the latest program is installed, do an ECM/PCM update whenever the
ECM/PCM is substituted or replaced.
– You can not update an ECM/PCM with the program it already has. It will only
accept a new program.
– Before you update the ECM/PCM, make sure the vehicle’s battery is fully
– To prevent ECM/PCM 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/PCM damage.
1. Turn the ignition switch ON (II). Do not start the engine.
2. Connect the HDS to the data link connector (DLC) (A) located under the
driver’s side of the dashboard.
3. Select the INSPECTION MENU with the HDS.
4. Do the TP LEARNING CHECK in the ETCS TEST.
5. If the HDS does not have the update function, disconnect the HDS from the
vehicle and connect the Honda Interface Module (HIM).
6. Do the ECM/PCM update procedure as described on the HIM label and in the
ECM/PCM update system.
7. Do the ECM/PCM idle learn procedure.
8. Clear the CKP pattern with the HDS while the engine is stopped.
How to Substitute the ECM/PCM
1. Remove the ECM/PCM from the vehicle.
2. Install a known-good ECM/PCM.
3. Rewrite the immobilizer code with the ECM/PCM replacement procedure in the
HDS; it allows you to start the engine.
4. After completing your tests, install the original ECM/PCM, and rewrite the
immobilizer code with the ECM/PCM replacement procedure in the HDS.
5. If you substitute a ECM/PCM select the INSPECTION MENU with the HDS, with the
original ECM/PCM installed.
6. Do the TP LEARNING CHECK in the ETCS TEST.
7. Replace the ECM/PCM, and rewrite the immobilizer code with the ECM/PCM
replacement procedure in the HDS.