Operation CHARM: Car repair manuals for everyone.
Home >> Honda >> 1999 >> Civic GX Sedan L4-1.6L CNG >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Relays and Modules - Computers and Control Systems >> Engine Control Module >> Service and Repair >> Known-Good ECM/PCM Substitution
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Known-Good ECM/PCM Substitution



How to Substitute the PCM

Use this procedure when you have to substitute a known-good PCM in a troubleshooting procedure.

1. Remove the PCM from the vehicle.
2. Install a known-good PCM in the vehicle.
3. Rewrite the immobilizer code with the PCM replacement procedure on the Honda PGM Tester. It allows you to start the engine.
4. After completing your tests, reinstall the original PCM and rewrite the immobilizer code with the PCM replacement procedure on the Honda PGM Tester again.


pro multis · About Operation CHARM