My computer died, or so the dealership said. We swapped the ECU for the one out of my brother's car (same year as mine). When we tried to start the car with my key, the car would crank but not start... and the immob light worked like normal. When I tried with a key cut to my car but without a chip, of course the immob light flashed the 4 times and it wouldn't even crank.

We then had the dealership program a T5 key to his code, and had the key cut to my ignition cylinder. When we tried to start the car the immob light flashed the 4 times indicating a wrong code and the car wouldn't crank.

I thought the code was stored in the ECU? Do we also need to swap the immob units to one setup for his code? I know the immob unit and the ECU do a handshake before the car will start.... my question is with my key and his ECU, did the immob light not flash because it recognized my key, but the ECU said "that key isn't right" and cut the fuel? This would explain why his code would cause the immob to flash and not even crank.

I'm just wondering if anyone else has replaced the ECU before and ran into this issue. We're going to have tempest racing take out his Immob unit and ship it up since his car is about 5-6 hours away down there... think this will fix my problem?

 

It should have started no prob. The immbolizer doesnt look for a specific signal, it just makes sure there is a signal comming from the key. Sounds like you have another issue or you could have possibly killed both ECU's.

 

keep us updated of what is wrong

 

alright i'll try. I have access to 1 more ECU. It's odd the 2nd one (my brother's) doesn't even attempt to fire up, just cranks.

 

Yo I had the same problem, u might want to check your ignition switch. I had a recall on mine and for that reason my car wouldn't start. Check for any recalls or check out the ignition switch. Just might be a possibility that is the problem if not then the immobilizer is reading something fishy and thats why its not gonna start

 

Ok,

It is my understanding that the immobilizer and the ECU are paired together.

The ECU needs to be told to recognize the immobilizer. This is done using a Honda Scan Tool.

There is a 30% chance that a different ECU will work with the immobilizer from a different car.

The best way to test is to swap them both over and use a T5 key cut to your ignition pattern. (That's actually how I perfromed my auto>manual swap...)

Keep in mind: The immobilizer cuts the ignition relay out, and the ECU controls the fuel pump... so if they are not speaking to each other, then the car may crank, but not get juice.



Modified by gerhard at 5:16 PM 12/17/2004

 

I had a recall on my ignition switch also.
I have a 97 SH. You might want to call Honda to find out. You might get it fixed for free!

 

You nailed it.

With his immob the car would fire up.. (besides the other issue)... So the immob cuts the ignition completely if it doesn't match the key, and the ECU will cut the fuel pump if the key doesn't match it. Sucks I didnt' have a red key for either setup, let alone the red key for the ECU didn't match my ignition.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by gerhard &raquo;</TD></TR><TR><TD CLASS="quote">Ok,

It is my understanding that the immobilizer and the ECU are paired together.

The ECU needs to be told to recognize the immobilizer. This is done using a Honda Scan Tool.

There is a 30% chance that a different ECU will work with the immobilizer from a different car.

The best way to test is to swap them both over and use a T5 key cut to your ignition pattern. (That's actually how I perfromed my auto&gt;manual swap...)

Keep in mind: The immobilizer cuts the ignition relay out, and the ECU controls the fuel pump... so if they are not speaking to each other, then the car may crank, but not get juice.

Modified by gerhard at 5:16 PM 12/17/2004</TD></TR></TABLE>

 

Gerhard's right. You need to swap over the immobilizer module with the ECU.

If you are good with a soldering iron, you can swap the immobilizer daughter board from the dead ECU into the good one.

You also need to match the ECU to the year of the car for '97 and '98. '99+ are usually the same.

I have a spare '97 P5M if anyone needs it.