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Discussion Starter · #1 ·
Hi everyone this is my first post on this forum, My name is Shawn and I drive a 2001 Prelude base. This may be a noob question but i have searched and cant seem to find the answer, I needed to replace my ecu and got one on order i should be receiving it friday.Since i am getting a new ecu do i have to get new keys or reprogram my old ones because of the immobilizer?Any help will be much appreciated, thanks
 

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i'm 90% sure i have a new ecu in my car, and it still starts with my key. but not being 100% sure, i can't say if you must get the new keys or not
 

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Discussion Starter · #3 ·
thanks Im hoping itll work as soon as i plug it in. I am hoping that this is my problem because the ecu got wet and the contacts were corroded if anyone can shine some light please do.
 

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you'll have to get the new ecu reprogrammed for your key or have new keys made.
 

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Discussion Starter · #6 ·
no, it is just the stock ecu not the type s, can a locksmith create new keys that'll work in my driveway or do i have to get it towed to the dealership? lilred i think yours worked because you have a "97 which i believe doesnt have the immobilizer.
 

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azianlude said:
no, it is just the stock ecu not the type s, can a locksmith create new keys that'll work in my driveway or do i have to get it towed to the dealership? lilred i think yours worked because you have a "97 which i believe doesnt have the immobilizer.
97 does have the immobilizer. The stealership had to make a new key for my car before they sold it as it wouldn't allow the old key to start the car sometimes.
 

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hunnhh?

I just switched to an OBD1 and my keys work fine.
 

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97 has the immoblizer. the green key still blinks when i put in my key, and i make a hardware store copy to see if it'd start the car and it didn't. so maybe he just never put in the type s ecu. he said he did though, and my key still starts the car.....


i'm like 6 hours east of roch. i went to school there and i bought my car there tho. i go every now and then
 

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lilredlude said:
see, my keys still work. but he said he put the type s ecu in. so i dunno
maybe the type s doesn't use an immobilizer? i'm not sure.

meshuggah said:
hunnhh?

I just switched to an OBD1 and my keys work fine.
right, obdI doesn't use an immobilizer, obdII does.
 

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Boosted521 said:
maybe the type s doesn't use an immobilizer? i'm not sure.



right, obdI doesn't use an immobilizer, obdII does.
no, cuz i had a non-chiped key cut at the hardware store to test it, and the car wouldn't start, the green key just flashed...
 

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azianlude said:
Hi everyone this is my first post on this forum, My name is Shawn and I drive a 2001 Prelude base. This may be a noob question but i have searched and cant seem to find the answer, I needed to replace my ecu and got one on order i should be receiving it friday.Since i am getting a new ecu do i have to get new keys or reprogram my old ones because of the immobilizer?Any help will be much appreciated, thanks
I hope you have the red learning key if not your going to need a new immobilizer unit to go with the ECU there are 2 ways of getting around this if you can soilder good and have a temp controlled iron just swap out the immobilizer board. the other is to replace the immobilizer board out with a bypass board. or you can just pay the $200 for the new immobilizer unit and have honda cut new keys and program the keys (expensive) or another option is to get the whole set if buying a junkyard ecu is to get the key immobilizer box + key and taking the key and having a T5 copy made.
 

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Discussion Starter · #16 ·
you guys have been very helpful, thanks for all the info, i found a locksmith who has tools to reflash my ecu to work with the my current keys, i appreciate all the help and am glad to be apart of your forum. Hope to get to know all you guys better. Keep your fingers cross for me, i hope this works. Thanks again
 

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I've been wondering about the immobilizer - ecu relationship for awhile. The common theme has been that the ECU is tied to the chip in the keys...

I'm currently running a P28, and the green light's behavior has been unchanged since I swapped out my OBD2 ECU.

When the car was stock, there were a couple of times (2-3, tops) where the car would not crank over when I put the key in and cranked it. The green light would flash and as I understood from the owner's manual that was a "normal" mis-read of the key. Reinserting the key fixed the issue.

Recently I had a similar thing happen with the OBD1 ecu in the car. If my ECU was responsible for immobilizing the car, that result doens't make sense.
I'm tempted to see what would happen if I used an unchipped cut of my key to start the car.
 

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Blue01 said:
I've been wondering about the immobilizer - ecu relationship for awhile. The common theme has been that the ECU is tied to the chip in the keys...

I'm currently running a P28, and the green light's behavior has been unchanged since I swapped out my OBD2 ECU.
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the immobilizer is a system coded keys,immobilizer control unit ,ecu when the key in turned on the immobilizer unit reads the key if the code is in it's memory it will handshake the ECU and the car will start up if not the immobilizer control unit will cut out the starter and the ECU will cut spark & fuel. since you replaced the ecu with a P28 the car will start without a coded key as long as the starter works or is pushed started. so the immobilizer unit can be disconnected and the 2 starter wires jumped blue and grey wires it will start with any key.
 

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stereo said:
the immobilizer is a system coded keys,immobilizer control unit ,ecu when the key in turned on the immobilizer unit reads the key if the code is in it's memory it will handshake the ECU and the car will start up if not the immobilizer control unit will cut out the starter and the ECU will cut spark & fuel. since you replaced the ecu with a P28 the car will start without a coded key as long as the starter works or is pushed started. so the immobilizer unit can be disconnected and the 2 starter wires jumped blue and grey wires it will start with any key.
So that explains the green light key flashing on p28 ecu. the immoblizer unit is still there .. wow

I just wanted say that to be a part of the thread i personally still have the stock ecu so you guys can't take my car :)
 

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Ricedadee said:
So that explains the green light key flashing on p28 ecu. the immoblizer unit is still there .. wow

I just wanted say that to be a part of the thread i personally still have the stock ecu so you guys can't take my car :)
the immobilizer control unit is under the dash on the left side of the colom it's black with white sticker on it that says honda lock.

I wouldn't say the the immobilizer is fool proof as honda keeps a database of the immobilizer brake brake code that alows the car to be driven with a standard metal key that can be cut with just the vin #
 
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