Known-Good ECM/PCM Substitution
On models equipped with engine immobilizer system, acquire key cut from non-immobilizer key blank. Remove ECM/PCM from test vehicle. Install known-good ECM/PCM from donor vehicle into test vehicle. Tape donor vehicle's ignition key head-to-head to test vehicles temporary key. ECM/PCM will recognize code from donor vehicle's key and allow test vehicle to be started.
ECM/PCM is part of immobilizer system. Replacement ECM/PCM must have immobilizer code rewritten, using Honda PGM Tester. To perform rewrite procedure requires the vehicle, all master keys, all valet keys and a Honda PGM Tester with an immobilizer program card. Any key not learned during rewrite will not start vehicle. Follow Honda PGM Tester instructions.