Update: Green Key lights whenever Ody accelerates. Unrelated to knock sensor issue. Knock sensor issue was a combination of rodent chewed harness at sensor and low quality aftermarket knock sensor. Replaced both with Honda Dealer parts and that problem is now 100% solved.
Green key light while driving appears to track manifold vacuum. I have swapped steering column immobilizer parts, keys, fobs, Instrument cluster, and PCM. The battery is new, the charging system operates within spec as designed. All associated wiring and grounding has been checked out. I have eliminated the keys and immobilizer systems as the cause. The signal to illuminate the Green Key is verified at the output of the PCM. I will be checking all PCM inputs like MAP sensor, TPS sensor etc. as time permits. The Ody starts and runs perfectly. It is just annoying to have that green key illuminate every time I press on the gas pedal. I have only seen one other identical case like this on the web with no adequate solution. Any Help would be greatly appreciated.

 

Battery Ground cable was bad near transmission connection. Increased resistance under load.
Replacement cable solved issue. More info at my post https://www.odyclub.com/threads/immobilizer-brake-code-explained-solved.375943/post-2572010

 

One Last thing:
My Ody always started and I never got the flashing Green Key "Lockout".
During my troubleshooting I totally ruled out key recognition and the Immobilizer Receiver Unit.
I discovered that once the Ody is started and running the immobilizer receiver can be unplugged, the green key will come on and the Ody will continue to run. The immobilizer only verifies the key before cranking the engine then it is out of the picture. (A nice fail-safe while driving system.)
My problem was with the indicator randomly illuminating while driving. Rarely at first, but eventually it came on whenever I pushed the gas pedal. This makes sense as my failing battery cable would only flex when the engine and transmission moved. If the problem got worse and the light came on when the engine was not running would the Ody still start? Was it simply a false indicator issue? I never found out. That is why I looked into the Brake Code immobilizer bypass procedure.
I do know first hand that the PGM FI (Main) Relay solder joint failure is a common reason for engine shut down while driving and also that relay failure (or relay hot wiring) triggers the immobilizer and prevents starting the Ody even with the correct key.

 

Great find and thanks for posting the solution!!
That is a difficult one to find.
Buffalo4

 

Thanks for that good opinion and research .
Buffalo4