Hi I found this forum, know very little about cars so bear with me. But, I could use some advice from those of you who know about this kind of stuff.

The whole story:

I inherited my dad's 2004 Honda Accord EX Automatic (I think it's v6 but I'm not sure, sorry) 138,000 miles on it at this point.

I believe he had the ignition replaced because the key for the ignition doesn't go into the door or any other locks and all I can really do with the key is lock and unlock the doors and start the car. I'm okay with that. I pop the trunk from inside the car. I understand replacing all the locks and new keys is expensive.

I have had the current key fob fixed a few times. I always had the chip and the metal stick part and a locksmith would put it into a new case, $75. Within a matter of months the key would break again so I just tape it shut or deal with it in pieces (This last time he glued the chip into the key with some kind of foam. It was fine for the last 6 months).

Now there seems to be an immobilizer or key problem. Sometimes I can't start the car and the green key is blinking when I take the key out. Sometimes then, I lock the doors while Im inside (with the key fob) and I can start the car. Sometimes I can start the car if I do that thing where I go from 0 to 2 back to 0, remove key, go back to 2. Sometimes that doesn't work. Maybe Im pressing the key in too much or not enough. Then I unlock the car or lock it again or do any number of things and it starts.

I ( lightly) popped the gas door with a screwdriver when it was frozen shut and the door isn't always closed. AutoZone tested the car and the report said loose gas cap. One day I got out and clicked the gas cap 3 times and then was able to start the car. Coincidence? I don't know.

Auto Zone suggested replacing the battery in the key fob and then amazingly the car starts! But not necessarily the next day or the next time without some trouble and trying.

I can't help but feel that this started sometime after I started accidently pressing buttons on the key fob. It was broken as it almost always is, and I was accidently hitting the panic button, etc. I'm wondering if I did something wrong or mis-set something.

It seems so much like it has to do with the key fob in some way or another.

Took it to a Honda dealer hoping to have it reprogrammed. I have reason to believe it was not properly diagnosed according to Honda protocols on the Honda diagnoser machine. Mechanic was just casually diagnosing the situation.

Receipt says: Technician found the immobilizer in the ignition cylinder failing to recognize the key, replace ignition cylinder.

He told me my key was fine.

I don't know what to believe. There was some double talking going on, not with the tech but certainly with the service advisors.

I know the last time I brought the key to be repaired the locksmith said something about how he can tell I got the key wet and I believe he had to clean off some corrosion on the inside. I did drop it into a cup of soda sometime this past this summer. Stuff happens.

So after 3 hrs and $186 for the "diagnosis" they told me it's an $1100 repair.
$500 for the part (ignition cylinder) and 3 hrs of labor at $179 per hour.

CAN SOMEBODY PLEASE ADVISE?

Meanwhile I never know for sure now if I can make it to work or not and I cant be missing work. I need to do something ASAP.

Thanks in advance, I would greatly appreciate an I formed opinion.

 

To tell if you have a 4-cyl or V6, open the hood. If the valve cover says 2.4L, then 4-cyl. 3.0 (or 3.#), the V6.

The gas cap issue would not cause your car to not start. The next time you get a code, record the actual code, because I suspect the code was for a large evap leak which the gas cap is one possible cause amongst others.

Your key with the door lock buttons integrated has 2 separate and independent functions, locking/unlocking and starting the vehicle.

The fob portion uses the small battery to remotely lock/unlock the doors.

For starting the car, the key is cut to turn the cylinder. There is also the immobilizer system, where your key has a radio frequency transponder that emits a radio signal with a unique code for your specific key. The immobilizer receiver in the lock cylinder detects the signal (just like a radio picking up a radio station) and sends that code to the engine computer (PCM). The PCM will allow the car to start if the code sent from your key, to the receiver, then to the PCM matches any key codes stored in your PCM. The transponder in your key does not work off the battery in your key.

The green light flashing is either due to the key not sending out a good signal, or the receiver in the immobilizer is not detecting signals anymore. It is possible the PCM or the wiring is the issue as well. Sounds like the Honda technician determined the receiver is the issue.

Are you wanting to do some DIY work to solve this problem?

 

Thank you so much for getting back to me. And thank you for the thorough explanation.

How involved would the DIY work be? I couldn't even find the valve cover just now. Is it something a lay person like myself would be able to handle?

My concern is that it's a just a fuse or something and this guy didn't even really diagnose it and I'm gonna wind up spending $1100 that I don't have for a new ignition.

The reason I mentioned the battery in the key fob was because I had found this online while googling. I thought maybe it would be a clue to what the problem is.

(Screenshot)

 

I wish I could post a link but I'm having a hard time doing it. I saw online a Honda troubleshooting guide for the immobilizer. It's not for my generation of Honda but there seems to be a specific set of steps to take when diagnosing to find out what the problem is, exactly. I don't believe the technician did this. I believe he is giving his best guess.

 

The V6 looks like this:



4-cyl like this:

 

For the DIY, it isn't too hard. The only difficult part is removing the tamper-proof bolts on the steering column. Watch the video below on removal of the lock cylinder to see what is required.. The immobilizer is transferred from the old to the new part. You can actually buy just the imobilizer receiver new for ~$150 and swap to your current lock cylinder. You'd also need new bolts to hold the lock cylinder, but you don't absolutely need to install tamper-proof bolts.

At minimum, I'd remove the covers on the steeringwheel and check that the immobilizer electrical connector is securely plugged in and the wires aren't damage near there, since a replacement lock cylinder was installed. The wire harness could have been routed wrong and is rubbing against something.

 

From the dealer's technician findings, it sounds more like just the Immobilizer Control Unit-Receiver needs replacement and programming. (If the Immobilizer Control Unit-Receiver, it must be programmed.)

See this service bulletin regarding the Type 4 Immobilizer System.
TSB 03-053


If the key and key cylinder works and the ignition switch (electrical portion) works, they wouldn't necessarily have to be replaced.

The Immobilizer Control Unit-Receiver is discontinued; so, may have to get a used one. Honda 39730-SDA-A11

 

Thanks so much for all the advice.
And now I know I have a 4 cylinder engine.

I'm not the type of woman who is afraid to chip a nail, but taking the steering wheel cover off, checking wires and possibly installing a new ignition myself I think may be a bit much for me. Because I really don't know what I'm doing or what wires I'm checking.

That was informative, the attachment. I didn't realize all that with the key codes.

About my car - now I know the green key light isn't flashing any differently than it should be flashing. 5 seconds after taking the key out.

I can't help but feel this is a key issue. I lock the doors /unlock the doors / do things with the locks on the remote combined with moving the key from 0 to 2 and I can get it to start. It's some combination I can't figure out with locking and unlocking the doors with the remote.
So theres no certaintly on if can get the car to start.

If this discontinued part needs to be replaced can a regular mechanic handle this or does it have to be a Honda dealership?

Should I have a locksmith fix this broken key and see if that helps before moving from mechanic to mechanic, all of them wanting to do their own diagnosis?

Thanks

 

If the immobilizer system is working properly, when you turn the key to the II position, but do not try to start the car, the green key light will turn on solid for 2 seconds then turn off. When you turn off the key, the green light will flash five times.

If the wrong key is used, turning the key to the II position will have the key light turn on for 2 seconds, then starts flashing every second until you turn off the key. When you turn off the key, the light should shut off and not flash.

Let us know what that green key light is doing using the above information.

 

Thanks for this!

I just went outside and the car started right up, I don't know why.

What happened was exactly what you said in the first paragraph. The light stayed on for 2 seconds and then blinked 5 when I took out the key.

I did it 2 times. The first time i might have jeard a very, very slight grind sound. Not the second time.

I don't know what to do as far as getting to work today. I dont leave for work for another 3 hrs. I am tempted to leave the car running for 3 hrs.