I just got another ecu for a 99 accord everything

new ecu -- key --vehicle all need to match[flashed ] should have just had dealer or authorized locksmith cut new key by vin

Because you have changed the Module twice, (to the replacement one then back again), You will have made the ECU, (the car's brain), think it is actually being stolen. You'll need a Good Auto Electrician to look at you vehicle to sort this out.
Anti-theft units are coded specifically to the vehicle it is originally fitted to and only that vehicle so it can communicate with the ECU and the Key fob. That means they are not normally a part you can just swap. The only way to swap them is to pay the Silly prices and get a Dealership to re-programme the ECU and the Anti theft module to match your vehicle.

What kind of code reader did you use ? Need one that can communicate with all modules on the vehicle . Changing a PCM / ECM from other vehicle ( don't care if it's matches your's ) still needs to be programmed . Your best bet ,take it to a qualified repair shop .

NO 94 is pre obd ll and ecu and ignition different in every way --cant be flashed and harness dont even hook up

Yes. problem is that some years won't sync with others. You should have gotten everything out of the same car. Then you wouldn't have to do anything except start and drive your car. you did get everything you needed, just got them out of two different cars. Codes won't match. 1 in 1000 chance they will match codes. I do this all the time, but you have to gt everything out of one car. ECM, BCM, Key,Ignition chip, and some times the instrument panel. And there is year specific, because of transmissions. But I can fix that problem also.

you may have to change the ecu , to match the vtec, because i dont think you can reprogram those ecu units.

Different make and model of cars have different location for it ECU however i most case the ECU is located in the passenger area or engine bay. If it is in the passenger area, most likely it is behind the radio in the center console or behind the glove box.

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99 Engine is OBD-II.

It must match with the same production line ECU.


You may luck out by getting the chip set for the ECU.


Did you purchase the 99 engine,ECU and the wiring set OFF THE SAME Jeep.

The key is to have a matching ECU firmware to drive the injectors and read ALL sensor.

Go to pick and pull and check out few ECU stock numbers and compare to your

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There is a "S" for stating it's an auto or stick.

The CPS crank position is differnrt between the two.

This can be your major miss-match.

As far as I know you need to replace the ECU, Immobilizer and the key switch as they are all programmed to talk to one another. You will need to re-program the replacement ECU.