Hey guys I found this forum while trying to search for answers. Hope someone can help me out.

I have a 99 accord with the v6. I just did put in a motor from an 01 accord in it. v6 also. Changed wire harness and computer. Had a friend who is a honda mechanic come over to reprogram the ecu to my key. Problem we are having is it wont take. We can get the car to start by using the brake bypass code. But it wont allow him to remove the keys programmed to it and add my key. It keeps saying either "immobilizer system cancelled" or "harness open or harness short".
The immobilizer harness was never touched. And I know the engine harness is good.

He is stumped and so am I. He said I may have to go back to the old harness and remove the coil pack set up and go back to a distributor. I dont really want to do that.

Does anyone have any ideas whatsoever?

 

The immobilizer harness OK all the way back to the PCM? Because the immobilizer stuff is just an RFID antenna near the ignition lock-cylinder. Stored key IDs are in the ECU, so it begins to sound like the immobilizer antenna might not be connected to the PCM?

 

We have never messed with the immobilizer. Havent even taken the column cover off. The only thing that has been touched inside the car was the ecu.

 

The immobilizer stuff is new to me. All my other hondas never had that. What I meant was the wiring that goes to the ecu from inside the car was never touched. Its all stock. Just plugged it into the new ecu

 

This is in line with what JimBlake mentioned.

This Honda TSB gives a description regarding the Immobilizer system for your car. http://www.tegger.com/hondafaq/tsb/accord/x97-058e.pdf

Attached is a partial picture of the Immobilizer circuit. The Immobilizer receiver harness appears to run from the steering column area, along the underside of the driver's dash to Connector C401, a 22-P Blue connector, which then runs to the harness connected to the PCM/ECM.

There does appear to be a difference for the brn/blk ground wires from the engine harness(for a V6 99 vs. V6 01) going into the junction connector C105 (located inside below the right dash area); however, I don't think that would cause the problem with the Immobilizer.

 

Hmmm yeah I wonder if its just different colored wiring.

 

For the 01 V6, a ground wire for the ABS/TCS control unit is added going into the C105 junction connector.

 

So is there a possibility the dash wiring may have to be swapped too? I am wondering if maybe the pins are in different locations on the plug due to the abs sensor and thats whats causing this

 

If the car started with the Immobilizer brake code, there may be no need for changing any other harness, etc. Sounds like a communication problem. Check connections, etc.

 

yeah but isnt that a code to bypass the immobilizer? If the wiring for the immobilizer is in a different spot but your bypassing it with the brake code it should still start possibly. Do you know anywhere I can look up the plugs to see what pins are where and see if there is a difference