Honda OEM immobilizer
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=52615
Printed Date: July 07, 2025 at 11:10 AM
Topic: Honda OEM immobilizer
Posted By: ss79
Subject: Honda OEM immobilizer
Date Posted: March 26, 2005 at 8:33 AM
Hi all I want to by-pass my Honda OEM immobilizer but cannot figure out how to do it ... Car is Honda Prelude (4th generation) 1995. My immobilizer works as this: I have one reader where i have to connect my "key". When this key has been connected for a while (about 2 seconds)led stops flashing which tells that immobilizer has been disabled. This is my "key": https://www2.lut.fi/~halaason/temp/key_en.jpg If I dont turn ignition key in 30 seconds, led starts flashing again and immobilizer is armed. I investigated reader and it contains 3 wires: 1 red which has about 1 - 2 volts for flashing led, 1 black which is ground and 1 white wire which has continously about 11,5v. When i put my "key" into reader voltage drops into ~9v and when i disconnect, it raises back to 11,5v. It seems that this key contains some resistor which does the work. When I followed the wires coming from this reader unit, I found this controller box:
https://www2.lut.fi/~halaason/temp/Picture%20018.jpg There were two heavier cables coming to box: one was from ignition switch and other one contained always 12v. Then there were three wires which came from key reader unit. Other wires were unknown to me. This is a picture which shows the cables:
https://www2.lut.fi/~halaason/temp/Picture%20021_en.jpg This picture shows also the connector from reader unit:
https://www2.lut.fi/~halaason/temp/Picture%20019_en.jpg Question: Is there easy way out to disable the whole immobilizer?
Replies:
Posted By: Ween
Date Posted: March 26, 2005 at 8:46 AM
it looks as if the unit is a simple plug in unit..no wires to cut. the connectors in the pics appear to have mating pieces...the unit disconnects various circuits via the main box. did you try to plug the connector ends in the car to a joining connector or part in the car? just a thought. mark
Posted By: ss79
Date Posted: March 26, 2005 at 9:35 AM
Mark: I didn't try that. It feels to me that there are too many wires wich would be left without joining connector if i remove the whole unit.
It is still unclear how this immobilizer actually works. When it is armed and i try to start the car, gauge lights come on normally, there is clicking sound from some relay (i believe it is PGM-FI main relay) but starter stays silent.
Posted By: profuse007
Date Posted: March 26, 2005 at 10:20 AM
first time seeing stand-alone antitheft unit. anyways, do you have to use a regular key along w/ the rectagular box key?
as far as disable the whole unit, just leave that antitheft unit out and follow Weens idea. ------------- Houston,TX
"The two most common elements in the universe are H+ and stupidity" (Ellison).
Posted By: ss79
Date Posted: March 26, 2005 at 11:53 AM
That rectagular box key reader is located in middle console and yes, I use my regular key to start the engine.
Have I understood you right: I should try to remove some connectors connecting to antitheft unit and connect those directly with each other (=bypass the whole antitheft unit) ?
Like I said, there are quite many cables going in and out from that box, this could be quite demanding task. Any ideas where to start ?
Posted By: accord78
Date Posted: March 26, 2005 at 1:42 PM
sup guys i was reading this post and i have a 98 accord with the oem immobilizer system in it the way mines work is the system needs a key that has sorta like a chip in it once u put that in the ignition switch it reads it and if the code is right the car will start and if u use the wrong key it will crank but won't start witch means it kills the fuel pump so it won't start i say if your going to rip that system out of your prelude i wouldn't do it beacuse if u do there might be some stuff u need in that system for the car to start i would leave it alone and if your installing and alarm or so use a 555u module.
Posted By: Ween
Date Posted: March 26, 2005 at 5:23 PM
ok from the 20019 pic, on the right side, it looks as if the three pin connectors are a mating set as are the eight? pin ones slightly to the left of those. that leaves the reader connector, two female tab connectors and a ground terminal. one of the female tab connectors appears to be fused (battery perhaps) which leaves the one wire left. if the connectors do mate up i'd try to trace the wiring back into the controller box more. the heavy gauge wire i bet is the starter interrupt circuit, the other connector for the fuel interrupt and maybe ignition coils too? which accounts for all the wiring (3 heavy duty relays in unit...start/fuel/spark). unfortunately it would help to see a closeup of both sides of the controller board. i'll try to help more if i can mark
Posted By: profuse007
Date Posted: March 26, 2005 at 6:37 PM
ss79] wrote:
Like I said, there are quite many cables going in and out from that box, this could be quite demanding task. Any ideas where to start ?
you can start w/ the IGN harness and plug it to the fuse box. i believe there are two of them.
whats your area location? ------------- Houston,TX
"The two most common elements in the universe are H+ and stupidity" (Ellison).
Posted By: ss79
Date Posted: March 27, 2005 at 6:05 AM
Thanks for giving me new ideas about this issue. Any help is truly appreciated...
Because this is OEM immobilizer (at least "Honda immobilizer" stickers in my windows tell it is) could it be that it is integrated so tight that it would impossible to remove it :-/
Well I must take the unit out, take more pictures and try to check if I can connect the car cables directly without passing the cables through immobilizer unit.
Posted By: accord78
Date Posted: March 27, 2005 at 12:06 PM
sup my question to u is why do u wanna take it out?????? just by pass it i don't get what your trying to do
Posted By: ss79
Date Posted: March 27, 2005 at 1:32 PM
I am installing new alarm to my car and that is why I am facing this problem. But to answer your question yes, it would be adequate only to bypass it (if I could find out how to do it).
Posted By: accord78
Date Posted: March 27, 2005 at 5:19 PM
oh that's easy If u have a spair key... you will need a spair key if u have 1 and buy yourself a dei 555u module that bypasses the immobilizer put your spair key in it and put the antenna wire around the receiver on the key cylinder and hook up like 3 wires to the alarm simple as that then when u remote start it will trick the computer.
|
